Source: KANSAS STATE UNIV submitted to NRP
LIPIDOMICS: EXPANSION AND UTILIZATION OF PLANT LIPID ANALYSIS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0225075
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Oct 1, 2011
Project End Date
Sep 30, 2016
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
KANSAS STATE UNIV
(N/A)
MANHATTAN,KS 66506
Performing Department
Biology
Non Technical Summary
Mass spectrometry-based lipid analyses will be used in agriculturally relevant research projects at Kansas State University and at other research institutions. In addition, analyses to identify and quantify oxidized membrane and related lipids involved in plant stress responses will be developed. Oxidized membrane lipids may function as mediators signaling stress responses, they may represent damage that could serve as a protective buffer against oxidative damage elsewhere in the cell, or they may be long-term modifications that might function as stress "memory". However, in contrast to oxylipins, such as jasmonic acid and its derivatives, whose significance in plant growth and defense to stress has been well documented, little is known about the functions of oxidized membrane lipids in plants. Oxidized phospholipids and oxidized galactolipids will be identified and quantified when plants are stressed in response to two abiotic (freezing and high salinity) and two biotic (infection by Botrytis cinerea and Pseudomonas syringae) stresses. Information about oxidized lipid formation during plant stress will be published and used in further studies aimed at identification and manipulation of the genes involved in oxidized lipid production and signaling. In the long term, the information will be used to identify and manipulate steps in membrane lipid metabolism to improve plant stress tolerance, product quality, and productivity.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
20624991000100%
Knowledge Area
206 - Basic Plant Biology;

Subject Of Investigation
2499 - Plant research, general;

Field Of Science
1000 - Biochemistry and biophysics;
Goals / Objectives
1. The capability to analyze plant lipids using mass spectrometry will be extended. Lipids provide the structural basis for cell membranes, fuels for metabolism, and intracellular, intercellular, and inter-organismic signals. In plants, lipids and their derivatives are involved in regulating processes that range from seed germination, growth, cell-patterning, organ differentiation, and reproduction to plant response to biotic and abiotic stresses. Assessing the role of lipids and lipid-related gene products in plants requires the ability to analyze lipids. Kansas Lipidomics Research Center (KLRC) has implemented and developed many rapid lipid analyses using mass spectrometry (MS), including analyses for membrane phosphoglycerolipids, sphingolipids, glycolipids, triacylglycerols, diacylglycerols, free fatty acids, and a number of oxidized lipid species. KLRC has six mass spectrometers and serves as a resource for lipid analysis for scientists from Kansas State and from around the world. However, reliable analyses for a number of lipid types are still lacking. These include many oxidized lipids, which are likely to be involved in plant stress signaling responses. Lipid analysis will continue to be developed and implemented: (i.) as needed by researchers who present projects to KLRC, and (ii.) targeted analyses for oxidized lipids (complex lipids, fatty acids, and sterols) produced in plant stress responses. 2. Molecular species and dynamics of oxidatively modified membrane lipids in plant response to abiotic and biotic stresses will be determined. Both biotic and abiotic plant stresses result in lipid oxidation, and a large body of knowledge indicates the importance of oxidized free fatty acids, also known as oxylipins, in plant stress responses. Recent studies in plants and animals indicate that oxidized complex lipids, such as phospholipids, are also produced in response to multiple stresses. In mammalian systems, specific ox-phospholipids have been identified as major regulators of many cell types. Unique to plants is the stress-induced production of oxidatively modified galactolipids. Data indicate that distinctive types of ox-lipids are produced in plant response to different stresses, such as freezing, wounding, and pathogen infection. However, the range of compounds produced, the timing of production, and the range of stresses that produce ox-lipids has not been investigated systematically. This project will identify and measure oxidatively modified membrane lipids in plants produced under specific stresses, along with the time frame of their accumulation in plant stress response. The project will produce large data sets of lipidomic data, data on stress phenotypes of plants with altered genetic composition, and publications. It will also produce new methods of lipid analysis that can be utilized in other research projects. In the long term, the understanding of the function of specific lipids, genes, and gene products will be utilized to produce crop varieties with improved stress resistance.
Project Methods
1. The capability to analyze plant lipids using mass spectrometry will be extended. When a researcher indicates the need to analyze a particular type of lipid, KLRC will utilize appropriate MS technology, applying electrospray direct infusion triple quadrupole (QqQ) MS for most analyses of complex lipids. Quadrupole time-of-flight (QTOF) MS will be applied for structural elucidation and where superior mass resolution of fragment ions is important. Gas chromatography (GC)-MS will be used for compounds that can be volatilized. GC-MS is particularly useful for compound identification if the compound has been analyzed previously and the detailed electron impact (EI)-MS spectra can be matched with spectra in a spectral library. There is also the option of high performance liquid chromatography (HPLC) MS for low-abundance compounds that need to be separated from other compounds to increase the signal (by reduction of ion suppression) and for resolution of the signal of interest from signals of other compounds with the same mass. For oxidized lipids, the comprehensive lipid profiling strategy will include direct infusion QqQ MS analysis for oxidized complex lipids, QTOF MS analysis for oxidized fatty acids, and GC-MS analysis of oxidized sterols. 2. Molecular species and dynamics of oxidatively modified membrane lipids in plant response to abiotic and biotic stresses will be determined. To determine molecular species and dynamics of oxidatively modified membrane lipids in plant response to biotic and abiotic stresses, profiles of ox-lipids will be systematically obtained. This will provide an underpinning for understanding ox-lipid biological function, as well as the biological function of the enzymes that produce and metabolize them. The ox-lipidome of Arabidopsis rosettes exposed to the four selected abiotic and biotic stresses: freezing, salinity, and infection with B. cinerea and P. syringae will be determined. Rosettes, collected at time points during stress, will be extracted, and mass spectra will be obtained for lipid identification and quantification. Lipids to be analyzed include ox-lipids, free and total oxidized fatty acids, and oxidized sterols; additional analytical targets will be added as feasible. Changes in lipids and the time frame of the lipid changes will be determined during each stress treatment. The changes in lipid species during stress response will be compared across stresses, and lipid changes common to multiple stresses and specific to a particular stress will be identified, using statistical analyses performed in collaboration with Gary Gadbury (Dept. of Statistics). Effects will be quantified for each lipid and results will be organized into a list of "important findings" (e.g., lipids whose levels are altered due to stress at a selected time period and when averaged across time periods). Lipid changes identified will include enzymatically and non-enzymatically produced changes. The functions of specific enzymes (lipases and lipoxygenases) involved in oxidatively-modified lipid production are being examined in other ongoing work in collaboration with X. Wang, J. Shah, and Gadbury.

Progress 10/01/11 to 09/30/16

Outputs
Target Audience:Plant scientists; lipid researchers; stress biologists; people interested in crop improvement and sustainability. In the long term, farmers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Participants: PI: Ruth Welti Technician, programmer(s): Mary R. Roth, Pamela Tamura, Libin Yao Postdoctoral trainees: Sunitha Shiva, Thilani Samarakoon Graduate students: Hieu Sy "Danny" Vu Undergraduate students: Morgan Armbruster, Madeline Colter, Samantha Elledge, Cora Farley, Sam Honey, Katherine Hwang, Kaleb Lowe, Hannah Lusk, Dedan McEllhiney, Allison McKiearnan, Goutham Neravetla, Gabrielle Phillips, Neema Prakash, Charles Roach, Madison Sparks, Roshni Singh, Laura Welti, Hollie Wickham, Kristen Wilbeck Additionally, students and postdocs in collaborator labs received training related to lipid analysis by mass spectrometry. Collaborators: Bill Bockus, Kansas State U; Kent Chapman, U of North Texas; Ming-Shun Chen, Kansas State U and USDA-ARS; Gary Gadbury, Kansas State U; Mahmoud Ghannoum, Case Western Reserve University; Aruna Kilaru, East Tennessee State U; Weiqi Li, Kunming Institute, PRC; Gerald Lushington, University of Kansas; Vara Prasad, KSU; Rebecca Roston, U of Nebraska; Jyoti Shah, U of North Texas; Kathrin Schrick, Kansas State U; Aaron Smalter-Hall, U of Kansas; Dieter Strack, Leibniz Institute of Plant Biochemistry, Halle, Germany; Lloyd Sumner, Samuel Roberts Noble Foundation; Harold Trick, Kansas State U; Xuemin Wang, Danforth Plant Science Center and U of Missouri-St. Louis, St. Louis, MO; Todd Williams, U of Kansas; Lieceng Zhu, Fayetteville State U, North Carolina Training and professional development: The postdoctoral trainees, the graduate student, and undergraduate students received training through their research involvement, which included working with plants and mass spectrometry. The postdoctoral trainees, the graduate student, and undergraduate students also received practice in presenting their work, giving 19 poster presentations and 9 talks to scientific audiences from 2011-2016. How have the results been disseminated to communities of interest?One outcome of our work is the publication of results in refereed journals. Welti is an active classroom teacher, who discusses plant stress, climate change, and interactions between crops and the environments in her role as an undergraduate instructor of Kansas State's introductory biology course. Welti also gave 23 talks on the group's work during the 5-year period at scientific meetings or universities. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? (Report on 2011-2016) One impact of this project was to greatly expand technical capability for "lipid profiling", or measuring the wide array of specific lipid molecules found in plants. Understanding lipid metabolism is of key importance for improving seed oils and understanding and improving plant responses to abiotic and biotic stresses. In the past, progress in this area has been hindered by a lack of ability to get detailed information on lipid composition. This project identified novel lipids and increased both the number or lipids analyzed and the rate of lipid analysis by mass spectrometry (MS). The technology has been made available to plant scientists pursuing crop improvement. A second impact of the project was increased understanding of lipid metabolism in seeds and in leaves of plants under basal conditions and during stress responses. We used lipid profiling to define the biochemistry associated with stress responses in plant leaves. For example, we defined lipid patterns associated with specific biotic (bacterial and fungal pathogens and an insect pest) and abiotic (aluminum, drought, heat, cold, and mechanical damage) stresses and with the levels of nutrients (nitrogen). Studies employing lipid analysis also defined the function of specific genes controlling stress responses and seed oil composition by comparing lipid profiles in both leaves and seeds of genetically unaltered and altered plants. The first goal of the project is to expand our capability to analyze plant lipids using mass spectrometry (MS). The outcomes of work toward this goal were: 1. Working with a bioinformatics team at the University of Kansas, we created a web application for processing data derived from MS for lipid analysis (Zhou et al., 2011). The application, LipidomeDB Data Calculation Environment is available for use by the scientific public. 2. in collaboration with Kathrin Schrick (KSU), we extended mass-spectrometry based lipid (i.e., lipidomic) analyses to steryl glycosides and acyl steryl glycosides, both important plant lipids, particularly in seeds (Schrick et al., 2011). 3. We described in detail the protocols for analysis of polar lipids using MS (Shiva et al., 2011). 4. With Aruna Kilaru (currently at East Tennessee State University) and Kent Chapman (University of North Texas), we extended MS-based lipid analyses to plant N-acyl phosphatidylethanolamines, lipids potentially important in signaling for seed production (Kilaru et al., 2012). 5. We published a detailed list of lipids and described the available MS evidence for all complex polar lipids discovered in the model plant Arabidopsis thaliana to date (Samarakoon et al., 2012). We added MS evidence in cases where it was lacking. 6. We extended MS-based lipid analyses by characterizing a large group of head-group-acylated monogalactosyldiacylglycerols (acMGDGs) (Vu et al. 2014, Physiol. Plant.). 7. With Maoyin Li (working with Xuemin Wang at University of Missouri-St. Louis and Danforth Plant Science Center), we developed a relatively rapid strategy for analyzing plant oils, i.e., triacylglycerols (Li et al., 2014). This approach should be useful to scientists and breeders seeking to modify plant oil composition. 8. We extended MS-based lipid analyses by characterizing a wide variety of plant lipids using a new platform based on multiple reaction monitoring with a high-sensitivity triple quadrupole mass spectrometer (Vu et al., 2014, Plant J). 9. A pipeline was established for placing lipid profiling data in the Plant/Eukaryotic and Microbial Systems Resource database (http://metnetdb.org/PMR/) at Iowa State University, and data from recent publications were added to the database (Vu et al., 2015). 10. With Vara Prasad's group (KSU), we developed an analytical approach for lipids from wheat (Narayanan et al., 2016; paper I). The second goal of the project is to determine molecular species and dynamics of oxidatively modified membrane lipids in plant response to abiotic and biotic stresses. The outcomes of work toward this goal were: 1. We completed characterization of 115 oxidatively modified plant polar lipids and determined how these lipids change in response to freezing stress, wounding, and bacterial infection of plants (Vu et al., 2011). 2. In collaboration with Xuemin Wang's lab (University of Missouri-St. Louis and Danforth Plant Science Center), we analyzed the effect of a lipid hydrolase, pPLAIIa on lipid composition, while our collaborators analyzed its effect of gene expression (Yang et al., 2012). Combined, the data imply that the enzyme negatively regulates production of oxidized free fatty acids that likely play a role in plant water loss. 3. With Wang's lab, we analyzed the effect of another phospholipase (PLDa1) on lipid composition, while our collaborators examined how the presence of the enzyme related to leaf stomatal opening (Guo et al., 2012). The results showed PLDa1 and another system interact to mediate stomatal closing in response to abscisic acid; the data have implications for plant resistance to drought. 4. We also analyzed lipids in a study by Jyoti Shah's lab (University of North Texas), aimed at further defining the function of dihydroxyacetone phosphate reductase, which is required for plant systemic acquired resistance (Lorenc-Kukula et al., 2012). The data indicate that both enzymatic function and plastid intracellular localization are required for the plant defense functions of this protein. 5. Working with William Bockus's group (KSU), we used MS to determine leaf polar lipid composition in 20 healthy wheat cultivars and determined the effect of tan spot, a fungal pathogen, on leaf lipid composition (Kim et al., 2013). Galactoglycerolipid content of healthy cultivars was strongly correlated with resistance to tan spot. 6. With Ming-Shun Chen's lab (KSU) and Lieceng Zhu (Fayetteville State University), we measured lipid composition of wheat infested with Hessian fly (Zhu et al., 2012). Many different lipid molecular species are decreased during infestation. Taken together with gene expression data, the results suggest that the production of an array of lipids is related to plant response, and to susceptibility or resistance, to Hessian fly (Zhu et al., 2012). 7. We identified changes that occur in plant leaf lipids during their diurnal cycles (Maatta et al 2012), showing that 2 minor polar lipids increase during the dark period of the diurnal cycle. 8. With Wang's lab, we analyzed the effect of nitrogen deprivation on soy lipids in the leaves and roots of the plants (Narasimhan et al., 2013) and examined the role of the lipid-metabolizing enzyme, phospholipase Db1,during bacterial infection of plants (Zhao et al., 2013). 9. With Maoyin Li (working with Wang), we analyzed the effect of a patatin-related phospholipase, pPLAIIId, on seed oil composition, demonstrating that this protein product serves to increase the accumulation of seed oil with fatty acids of 20 or more carbons (Li et al., 2013). 10. We measured oxidized and many other stress-induced plant lipids under wounding stress (Vu et al., 2014). We analyzed lipid co-occurrence among samples and treatments by calculating correlation coefficients among all lipid pairs. Clusters of co-occurring lipids were identified as lipids with shared metabolism (Vu et al., 2014). 11. We utilized MS-based lipid analyses to analyze an extensive array of lipid in plants mutant in the gene SENSITIVE TO FREEZING 2 (SFR2) (Vu et al., 2015). The data demonstrated that SFR2 is responsible for all poly-galactosylation of chloroplast lipids during the plant wounding response. 12. With Vara Prasad's group (KSU), we analyzed lipids, including stress-induced lipids, during heat stress in wheat and associated particular lipid changes with heat damage in the examined lines (Narayanan et al., 2016; two papers in Plant Cell Environ.).

Publications

  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Schrick, K., Shiva, S., Arpin, J., Delimont, N., Isaac, G., Tamura, P., and Welti, R. (2012). Steryl glucoside and acyl steryl glucoside analysis of Arabidopsis seeds by electrospray ionization tandem mass spectrometry. Lipids. 47, 185-193. doi: 10.1007/s11745-011-3602-9.
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Lee, J., Welti, R., Roth, M., Schapaugh, W.T., Li, J., and Trick, H. (2012). Enhanced seed viability and lipid compositional changes during natural aging by suppressing phospholipase D alpha in soybean seed. Plant Biotechnol. J. 10, 164-173. DOI: 10.1111/j.1467-7652.2011.00650.x PMID: 21895945
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Shiva, S.*, Vu, H.S.* (*equal contributions), Roth, M.R., Zhou, Z., Marepally, S.R., Nune, D.S., Lushington, G.H., Visvanathan, M., and Welti, R. (2013). Lipidomic analysis of plant membrane lipids by direct infusion tandem mass spectrometry. In Plant Lipid Signaling Protocols, Methods in Molecular Biology. Ed. Teun Munnik and Ingo Heilmann. Humana Press, New York, NY. 1009, 79-91. doi: 10.1007/978-1-62703-401-2_9.
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Vu, H.S., Tamura, P., Galeva, N.A., Chaturvedi, R., Williams, T.D., Wang, X., Shah, J., and Welti, R. (2012). Direct infusion mass spectrometry of oxylipin-containing Arabidopsis thaliana membrane lipids reveals varied patterns in different stress responses. Plant Physiol. 58, 324-339. doi: 10.1104/pp.111.190280.
  • Type: Journal Articles Status: Published Year Published: 2011 Citation: Zhao, J., Wang, C., Welti, R., Bedair, M., Sumner, L., Baxter, I., and Wang, X. (2011). Suppression of phospholipase D gammas confers increased aluminum resistance in Arabidopsis thaliana. PLoS One. 6, e28086. doi: 10.1371/journal.pone.0028086.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Kim, D., Jeannotte, R., Welti, R., and Bockus, W.W. (2013). Lipid profiles in wheat cultivars resistant and susceptible to tan spot and the effect of disease on the profiles. Phytopathology 103, 74-80. doi: 10.1094/PHYTO-05-12-0099-R.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Li, M., Baughman, E., Roth, M.R., Han, X., Welti, R., and Wang, X. 2014. Quantitative profiling and pattern analysis of triacylglycerol species in Arabidopsis seeds by electrospray ionization mass spectrometry. Plant J. 77, 160-172. doi: 10.1111/tpj.12365.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Vu, H.S., Roth, M.R., Tamura, P., Samarakoon, T., Shiva, S., Honey, S., Lowe, K., Schmelz, E.A., Williams, T.D., and Welti, R. 2014. Head-group acylation of monogalactosyldiacylglycerol is a common stress response, and the acyl-galactose acyl composition varies with the plant species and applied stress. Physiol. Plant. 150, 517-528. doi: 10.1111/ppl.12132.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Narayanan, S., Prasad, P.V.V., and Welti, R. 2016. Wheat leaf lipids during heat stress: II. Lipids experiencing coordinated metabolism are detected by analysis of lipid co-occurrence. Plant Cell Environ. 39, 608-617. doi: 10.1111/pce.12648.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Vu, H.S., Shiva, S., Hall, A.S., and Welti, R. 2014. A lipidomic approach to identify cold-induced changes in Arabidopsis membrane lipid composition. In Plant Cold Acclimation, Methods in Molecular Biology. Ed., D. Hincha. Humana Press, New York, NY. 1166, 199-215. doi: 10.1007/978-1-4939-0844-8_15.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Narayanan, S., Tamura, P.J., Roth, M.R., Prasad, P.V.V., and Welti, R. 2016. Wheat leaf lipids during heat stress: I. High day and night temperatures result in major lipid alterations. Plant Cell Environ. 39, 787-803. doi: 10.1111/pce.12649.


Progress 10/01/14 to 09/30/15

Outputs
Target Audience:Plant scientists; lipid researchers; stress biologists; people interested in crop improvement and sustainability. In the long term, farmers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project involved a postdoctoral trainee, Sunitha Shiva, six undergraduate students, Hollie Wickham, Cora Farley, Madeline Colter, Goutham Neravetla, Kristen Wilbeck, and Gabrielle Phillips and a high school student, Katherine Hwang. The postdoctoral trainee, undergraduate students, and high school student received training through their research involvement, which included working with plants and mass spectrometry. Former graduate student Hieu Sy Vu and postdoc Sunitha Shiva were authors of the published work (Vu et al., 2015). How have the results been disseminated to communities of interest?One outcome of our work is the publication of results in a refereed journal. Welti is an active classroom teacher, who discusses plant stress, climate change, and interactions between crops and the environments in her role as an undergraduate instructor of Kansas State's introductory biology course. What do you plan to do during the next reporting period to accomplish the goals?We are actively engaged in further analysis of lipid changes and other plant responses to cold, freezing, heat, and bacterial infection. A lipid analytical screen of mutants and putative mutants in lipid analysis for stress-induced lipid changes was completed in 2015; further analysis of the mutants with compositions differing from wild-type plants is underway. Trainees at levels from undergraduate through postdoctoral associate will continue to be involved. In 2015, on a fee-for-service basis, the Kansas Lipidomics Research Center continued to offer its lipid profiling capabilities to researchers seeking to identify the function of plant lipid metabolizing and lipid signaling genes. The researchers using the KLRC are located around the world. This service will be continued in the upcoming year. The long-term goal of "Lipidomics" is to understand how cellular lipids and their metabolites interact to produce and maintain complex cell membranes and to regulate organismal functions. We are using lipid profiling data in collaboration with Xuemin Wang (U of Missouri-St.Louis) and Jyoti Shah (U of North Texas) to identify and manipulate steps in membrane lipid metabolism to improve plant stress tolerance, product quality, and productivity.

Impacts
What was accomplished under these goals? The first goal of the project is to expand our capability to analyze plant lipids using mass spectrometry (MS). The second goal is to determine molecular species and dynamics of oxidatively modified membrane lipids in plant response to abiotic and biotic stresses. In 2015, we utilized MS-based lipid analyses to analyze an extensive array of lipid in plants mutant in the gene SENSITIVE TO FREEZING 2 (SFR2) (Vu et al., 2015). The data demonstrated that SFR2 is responsible for all poly-galactosylation of chloroplast lipids during the plant wounding response. Additionally, a pipeline was established for placing lipid profiling data in the Plant/Eukaryotic and Microbial Systems Resource database (http://metnetdb.org/PMR/) at Iowa State University, and data from recent publications were added to the database. A wide range of stress-induced lipids are produced in wheat, maize, and the model plant Arabidopsis thaliana after heat and/or wounding stress. We measured oxidized and many other stress-induced lipids during heat stress in wheat and associated particular lipid changes with heat damage in the examined lines. Two papers describing this work were accepted in Plant, Cell and Environment.Ongoing projects are quantifying many stress-induced lipids in maize, in collaboration with Mitch Tuinstra's group at Purdue, and in sorghum, in collaboration with Geoffrey Morris' and Krishna Jagadish's groups at Kansas State.

Publications

  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Vu, H.S., Roston, R., Shiva, S., Hur, M., Wurtele, E.S., Wang, X., Shah, J., and Welti, R. 2015. Modifications of membrane lipids in response to wounding of Arabidopsis thaliana leaves. Plant Signal. Behav. 10, e1056422.
  • Type: Journal Articles Status: Accepted Year Published: 2015 Citation: Narayanan, S., Tamura, P.J., Roth, M.R., Prasad, P.V.V., and Welti, R. 2015. Wheat leaf lipids during heat stress: I. High day and night temperatures result in major lipid alterations. Plant Cell Environ.
  • Type: Journal Articles Status: Accepted Year Published: 2015 Citation: Narayanan, S., Prasad, P.V.V., and Welti, R. 2015. Wheat leaf lipids during heat stress: II. Lipids experiencing coordinated metabolism are detected by analysis of lipid co-occurrence. Plant Cell Environ.


Progress 10/01/13 to 09/30/14

Outputs
Target Audience: Plant scientists; lipid researchers; stress biologists; people interested in crop improvement and sustainability. In the long term, farmers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? The project involved a postdoctoral trainee, Sunitha Shiva, a graduate student,Hieu Sy "Danny" Vu, who obtained his Ph.D. in 2014, seven undergraduate students, Samantha Elledge, Dedan McEllhiney, Neema Prakash, Hollie Wickham, Laura Welti, Cora Farley, and Madeline Colter, and a high school student, Katherine Hwang. The postdoctoral trainee, the graduate student, undergraduate students, and high school student received training through their research involvement, which included working with plants and mass spectrometry. Undergraduate Dedan McEllhiney and former undergraduate student lab member, Sam Honey, were co-authors on a recent publication (Vu et al., 2014). How have the results been disseminated to communities of interest? One outcome of our work is the publication of results in a refereed journal. Welti is an active classroom teacher, who discusses plant stress, climate change, and interactions between crops and the environments in her role as an undergraduate instructor of Kansas State's introductory biology course. What do you plan to do during the next reporting period to accomplish the goals? We are actively engaged in further analysis of lipid changes and other plant responses to cold, freezing, heat, and bacterial infection. A new project that will yield results in the coming year is a lipid analytical screen of mutants and putative mutants in lipid analysis for stress-induced lipid changes. Trainees at levels from undergraduate through postdoctoral associate will continue to be involved. In 2014, on a fee-for-service basis, the Kansas Lipidomics Research Center continued to offer its lipid profiling capabilities to researchers seeking to identify the function of plant lipid metabolizing and lipid signaling genes. The researchers using the KLRC are located around the world. This service will be continued in the upcoming year. The long-term goal of "Lipidomics" is to understand how cellular lipids and their metabolites interact to produce and maintain complex cell membranes and to regulate organismal functions. We are using lipid profiling data in collaboration with Xuemin Wang (U of Missouri-St.Louis) and Jyoti Shah (U of North Texas) to identify and manipulate steps in membrane lipid metabolism to improve plant stress tolerance, product quality, and productivity.

Impacts
What was accomplished under these goals? The first goal of the project is to expand our capability to analyze plant lipids using mass spectrometry (MS). In 2014, we extended MS-based lipid analyses by characterizing a wide variety of plant lipids using a new platform based on multiple reaction monitoring with a high-sensitivity triple quadrupole mass spectrometer (Vu et al. 2014). Lipids analyzed included galactolipids and phospholipids (including monoacyl molecular species, molecular species with oxidized acyl chains, phosphatidic acids, tri-and tetra-galactosyldiacylglycerols, head-group-acylated galactolipids, head-group-acylated phosphatidylglycerol), sulfoquinovosyldiacylglycerols, sphingolipids, di- and tri-acylglycerols, and sterol derivatives. The second goal is to determine molecular species and dynamics of oxidatively modified membrane lipids in plant response to abiotic and biotic stresses. Oxidatively modified lipids are produced in wheat, maize, and the model plant Arabidopsis thaliana in response to environmental stress. We measured oxidized and many other stress-induced lipids under wounding stress (Vu et al., 2014 for Arabidopsis). We analyzed lipid co-occurrence among samples and treatments by calculating correlation coefficients among all lipid pairs. Clusters of co-occurring lipids were identified as lipids with shared metabolism (Vu et al., 2014). Ongoing projects are quantifying many stress-induced lipids in wheat, in collaboration with Vara Prasad's KSU group, and in maize, in collaboration with Mitch Tuinstra's group at Purdue.

Publications

  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Vu, H.S., Shiva, S., Roth, M.R., Tamura, P., Zheng, L., Li, M., Sarowar, S., Honey, S., McEllhiney, D., Hinkes, P., Seib, L., Williams, T.D., Gadbury, G., Wang, X., Shah, J., and Welti, R. Lipid changes after leaf wounding in Arabidopsis thaliana: Expanded lipidomic data form the basis for lipid co-occurrence analysis. Plant J. 80, 728-743.


Progress 01/01/13 to 09/30/13

Outputs
Target Audience: Plant scientists; lipid researchers; stress biologists; people interested in crop improvement and sustainability. In the long term, farmers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? The project involved a postdoctoral trainee, Sunitha Shiva, a graduate student, Hieu Sy “Danny” Vu, and nine undergraduate students, Morgan Armbruster, Samantha Elledge, Sam Honey, Dedan McEllhiney, Neema Prakash, Charles Roach, Roshni Singh, Madison Sparks, and Hollie Wickham. The postdoctoral trainee, the graduate student, and undergraduate students received training through their research involvement, which included working with plants and mass spectrometry. H.S. “Danny” Vu and Sunitha Shiva presented posters in January at the Gordon Research Conference on Plant Lipids: Structure, Metabolism, and Function. Welti served as chair of the Gordon Research Conference on Plant Lipids to be held in 2013 in Galveston, TX, and Danny Vu chaired the corresponding student-postdoc Gordon Research Seminar. Undergraduate Morgan Armbruster presented posters at the Kansas-INBRE and the KSU Developing Scholars symposia. Sam Honey and former undergraduate lab member, Kaleb Lowe, were co-authors on a recent publication (Vu et al., 2013a). How have the results been disseminated to communities of interest? One outcome of our work is the publication of results in refereed journals. Welti is an active classroom teacher, who discusses plant stress, climate change, and interactions between crops and the environments in her role as an undergraduate instructor of Kansas State's introductory biology course. What do you plan to do during the next reporting period to accomplish the goals? We are actively engaged in further analysis of lipid changes and other plant responses to cold, freezing, heat, and bacterial infection. A manuscript that details a very comprehensive lipid analytical approach applied to lipids in plants undergoing wounding is in preparation. Trainees at levels from undergraduate through postdoctoral associate will continue to be involved. In 2013, on a fee-for-service basis, the Kansas Lipidomics Research Center continued to offer its lipid profiling capabilities to researchers seeking to identify the function of plant lipid metabolizing and lipid signaling genes. The researchers using the KLRC are located around the world. This service will be continued in the upcoming year. The long-term goal of “Lipidomics” is to understand how cellular lipids and their metabolites interact to produce and maintain complex cell membranes and to regulate organismal functions. We are using lipid profiling data in collaboration with Xuemin Wang (U of Missouri-St.Louis) and Jyoti Shah (U of North Texas) to identify and manipulate steps in membrane lipid metabolism to improve plant stress tolerance, product quality, and productivity.

Impacts
What was accomplished under these goals? The first goal of the project is to expand our capability to analyze plant lipids using mass spectrometry (MS). In 2013, we extended MS-based lipid analyses by characterizing a large group of head-group-acylated monogalactosyldiacylglycerols (acMGDGs), which are derived from the chloroplast structural lipid class, monogalactosyldiacylglycerols (Vu et al 2013a). The second goal is to determine molecular species and dynamics of oxidatively modified membrane lipids in plant response to abiotic and biotic stresses. Indeed, acMGDGs are produced in wheat, tobacco, and the model plant Arabidopsis thaliana in response to environmental stress. The specific molecular species of acMGDGs depend on the stress and the plant species, but oxidative modification is common in this lipid class. In Arabidopsis, freezing, wounding, and bacterial infection all evoked strong production of acMGDGs; the slow kinetics of acMGDG synthesis, along with the high content of oxidized fatty acids, suggest a possible role in sequestration of harmful lipid metabolites (Vu et al 2013a). Related to probing the roles of lipids in stresses, we published a paper (in press) describing methods for measuring lipid changes during cold and freezing events (Vu et al 2013b). In collaboration with X Wang’s lab, we analyzed the effect of nitrogen deprivation on soy lipids in the leaves and roots of the plants (Narasimhan et al 2013) and examined the role of the lipid-metabolizing enzyme, phospholipase Dβ1, during bacterial infection of plants (Zhao et al 2013). We also utilized lipid profiling to address other questions related to lipid production in plants. With Maoyin Li, a research assistant professor associated with Wang’s lab, we analyzed the effect of a patatin-related phospholipase, pPLAIIIδ, on seed oil composition, demonstrating that this protein product serves to increase the accumulation of seed oil with fatty acids of 20 or more carbons (Li et al 2013a). Also with Li, we developed a relatively rapid strategy for analyzing plant oils, i.e. triacylglycerols, in considerable detail (Li et al 2013b). This approach should be useful to scientists and breeders seeking to modify plant oil composition.

Publications

  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Li, M., Bahn, S.C., Fan, C., Li, J., Phan, T., Ortiz, M., Roth, Mary R., Welti, R., and Wang, X. 2013a. Patatin-related phospholipase pPLAIII? increases seed oil content with long-chain fatty acids in Arabidopsis. Plant Physiol. 162, 39-51.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Li, M., Baughman, E., Roth, M.R., Han, X., Welti, R., and Wang, X. 2013b. Quantitative profiling and pattern analysis of triacylglycerol species in Arabidopsis seeds by electrospray ionization mass spectrometry. Plant J. In press.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Narasimhan, R., Wang, G., Roth, M., Welti, R., and Wang, X. 2013. Differential changes in galactolipid and phospholipid species in soybean leaves and roots under nitrogen deficiency and after nodulation. Phytochem. 96, 81-91.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Vu, H.S., Roth, M.R., Tamura, P., Samarakoon, T., Shiva, S., Honey, S., Lowe, K., Schmelz, E.A., Williams, T.D., and Welti, R. 2013a. Head-group acylation of monogalactosyldiacylglycerol is a common stress response, and the acyl-galactose acyl composition varies with the plant species and applied stress. Physiol. Plant. In press.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Vu, H.S., Shiva, S., Hall, A.S., and Welti, R. 2013b. A lipidomic approach to identify cold-induced changes in Arabidopsis membrane lipid composition. In Plant Cold Acclimation, Methods in Molecular Biology. Ed., D. Hincha. Humana Press, New York, NY. In press.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Zhao, J., Devaiah, S.P., Wang, C., Li, M., Welti, R., and Wang, X. 2013. Arabidopsis phospholipase D?1 modulates defense responses to bacterial and fungal pathogens. New Phytol. 199, 228-240.


Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: The first goal of the project is to expand our capability to analyze plant lipids using mass spectrometry (MS). In 2012, with A Kilaru and K Chapman, we extended MS-based lipid analyses to plant N-acyl phosphatidylethanolamines, lipids potentially important in signaling for seed production (Kilaru et al 2012). Working with the KU bioinformatics team, we expanded the ability of the web application (http://lipidome.bcf.ku.edu:9000/Lipidomics/) for processing MS data for lipid analysis. The application is available to the scientific public. The second goal is to determine molecular species and dynamics of oxidatively modified membrane lipids in plant response to abiotic and biotic stresses. In response to this goal, we published a detailed list of lipids and described the MS evidence for all complex polar lipids discovered in the model plant Arabidopsis thaliana to date (Samarakoon et al., 2012). As we compiled the summary, we further defined some structures and included the data. In collaboration with X Wang's lab, we analyzed the effect of a lipid hydrolase, pPLAIIa on lipid composition, while our collaborators analyzed its effect of gene expression (Yang et al 2012). Combined, the data imply that this enzyme negatively regulates production of oxidized free fatty acids that are likely to play a role in plant water loss. We also utilized lipid profiling to address other questions related to stress responses of crop and model plants. Also with Wang's lab, we analyzed the effect of another phospholipase (PLDa1) on lipid composition, while our collaborators examined how the presence of the enzyme related to leaf stomatal opening (Guo et al 2012). The results showed PLDa1 and another system interact to mediate stomatal closing in response to abscisic acid; the data have implication for plant resistance to drought. We also analyzed lipid in a study, by J Shah's lab, aimed at further defining the function of dihydroxyacetone phosphate reductase, which is known to be required for plant systemic acquired resistance (Lorenc-Kukula et al 2012). The data indicated that both enzymatic function and plastid intracellular localization are required for the plant defense functions of this protein. Working with W Bockus's group, we used MS to determine leaf polar lipid composition in 20 healthy wheat cultivars, and determined the effect of tan spot, a fungal pathogen, on leaf lipid composition (Kim et al 2012). The data indicated that galactoglycerolipid content of healthy cultivars was strongly correlated with resistance to tan spot. With M-S Chen's lab and L Zhu, we measured lipid composition of wheat infested with Hessian fly (Zhu et al 2012). It was determined that many different lipid molecular species are decreased during infestation. Taken together with gene expression data, the results suggest that the production of an array of lipids is related to plant response, and to susceptibility or resistance, to Hessian fly (Zhu et al 2012). Additionally, we identified changes that occur in plant leaf lipids during their diurnal cycles (Maatta et al 2012). We showed that 2 minor polar lipids increase during the dark period of the diurnal cycle. PARTICIPANTS: PI: Ruth Welti Technician, programmer(s): Mary R Roth, Pamela Tamura, Libin Yao Postdoctoral trainees: Sunitha Shiva, Thilani Samarakoon Graduate students: Hieu Sy "Danny" Vu Undergraduate students: Sam Honey, Charles Roach, Morgan Armbruster, Allison McKiearnan, Kaleb Lowe, Neema Prakash, Madison Sparks Collaborators: Bill Bockus, Kansas State U; Kent Chapman, U of North Texas; Ming-Shun Chen, Kansas State U and USDA-ARS; Gary Gadbury, Kansas State U; Aruna Kilaru, East Tennessee State U; Jyoti Shah, U of North Texas; Kathrin Schrick, Kansas State U; Aaron Smalter-Hall, U of Kansas; Harold Trick, Kansas State U; Xuemin Wang, Danforth Plant Science Center and U of Missouri-St. Louis, St. Louis, MO; Todd Williams, U of Kansas; Lieceng Zhu, Fayetteville State U, North Carolina Training opportunities: The postdoctoral trainees, the graduate student, and undergraduate students received training through their research involvement. Danny Vu, Thilani Samarakoon, and Sunitha Shiva presented posters in March at the Midwest meeting of the American Society for Plant Biologists (Lincoln, NE). Ruth Welti had meetings with the undergraduates students throughout the summer. Welti and two undergraduates, Kaleb Lowe and Neema Prakash, traveled to U of North Texas for a meeting of the undergraduate group of the Great Plains Plant Lipidomics Conference in July. Welti presented work in seminars at Samuel Roberts Noble Foundation in Oklahoma in March, at Washington State U in April, and at a meeting of LIPID MAPS in San Diego in May. She is serving as chair of the Gordon Research Conference on Plant Lipids to be held in 2013 in Galveston, TX, while Danny Vu is chairing the corresponding student-postdoc Gordon Research Seminar. Welti, Vu, Samarakoon, and Shiva traveled to U of Nebraska in February, to meet with Gordon Conference co-chairs and committee members for planning purposes. TARGET AUDIENCES: Plant scientists; lipid researchers; stress biologists; people interested in crop improvement and sustainability. In the long term, farmers. PROJECT MODIFICATIONS: None.

Impacts
One outcome of our work is the publication of results in refereed journals. In 2012, on a fee-for-service basis, the Kansas Lipidomics Research Center continued to offer its lipid profiling capabilities to researchers seeking to identify the function of plant lipid metabolizing and lipid signaling genes. The researchers using the KLRC are located around the world. The long-term goal of "Lipidomics" is to understand how cellular lipids and their metabolites interact to produce and maintain complex cell membranes and to regulate organismal functions. We are using lipid profiling data in collaboration with Xuemin Wang (University of Missouri-St.Louis) and Jyoti Shah (University of North Texas) to identify and manipulate steps in membrane lipid metabolism to improve plant stress tolerance, product quality, and productivity.

Publications

  • Guo, L., Mishra, G., Markham, J., Li, M., Tawfall, A., Welti, R., and Wang, X. (2012). Connections between sphingosine kinase and phospholipase D in the abscisic acid signaling in Arabidopsis. J. Biol. Chem. 287, 8286-8296.
  • Kilaru, A.*, Tamura, P.* (* = equal contribution), Isaac, G., Welti, R., Venables, B. J., Seier, E., and Chapman, K.D. (2012). Lipidomic analysis of N-acylphosphatidylethanolamine molecular species in Arabidopsis suggests feedback regulation by N-acylethanolamines. Planta 236, 809-824.
  • Maatta, S., Scheu, B., Roth, M.R., Tamura, P., Li, M., Williams, T.D., Wang, X., and Welti, R. (2012). Levels of Arabidopsis thaliana leaf phosphatidic acids, phosphatidylserines, and most trienoate-containing polar lipid molecular species increase during the dark period of the diurnal cycle. Front. Plant Sci. 3:49. doi: 10.3389/fpls.2012.00049.
  • Samarakoon, T.*, Shiva, S.* (* = equal contribution), Lowe, K., Tamura, P., Roth, M.R., and Welti, R. (2012). Arabidopsis thaliana membrane lipid molecular species and their mass spectral analysis. In High throughput phenotyping in plants, Methods in Molecular Biology. Ed., J. Normanly. Humana Press, New York, NY. 918, 179-268.
  • Yang, W., Zheng, Y., Bahn, S.C., Pan, X., Li, M., Vu, H.S., Roth, M.R., Scheu, B., Welti, R., and Wang, X. (2012). Patatin-related phospholipase A pPLAIIα modulates oxylipin formation and water loss in Arabidopsis thaliana. Mol. Plant. 5, 452-460.
  • Zhu, L., Liu, X., Wang, H., Khajuria, C., Reese, J.C., Whitworth, R.J., Welti, R., and Chen, M.-S. (2012). Rapid mobilization of membrane lipids in wheat leaf-sheaths during incompatible interactions with Hessian fly. MPMI 25, 920-930.-
  • Kim, D., Jeannotte, R., Welti, R., and Bockus, W.W. (2012). Lipid profiles in wheat cultivars resistant and susceptible to tan spot and the effect of disease on the profiles. Phytopathology In press.
  • Lorenc-Kukula, K., Chaturvedi, R., Roth, M., Welti, R., and Shah, J. (2012). Biochemical and molecular-genetic characterization of SFD1's involvement in lipid metabolism and defense signaling. Front. Plant Sci. 3:26. doi: 10.3389/fpls.2012.00026


Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: The first goal of the project is to expand our capability to analyze plant lipids using mass spectrometry. In 2011, in collaboration with Kathrin Schrick, we extended mass-spectrometry based lipid (i.e. lipidomic) analyses to steryl glycosides and acyl steryl glycosides, both important plant lipids, particularly in seeds (Schrick et al., 2011). We described in detail the protocols for analysis of polar lipids using mass spectrometry (Shiva et al., 2011). Working with the bioinformatics team at the University of Kansas, we created a web application for processing data derived from mass spectrometry for lipid analysis (Zhou et al., 2011). The application, LipidomeDB Data Calculation Environment is now available for use by the scientific public (http://lipidome.bcf.ku.edu:9000/Lipidomics/). The second goal of the project is to determine molecular species and dynamics of oxidatively modified membrane lipids in plant response to abiotic and biotic stresses. In direct response to this goal, we completed characterization of 115 oxidatively modified plant polar lipids and determined how these lipids change in response to freezing stress, wounding, and bacterial infection of plants (Vu et al., 2011). We also utilized the technology in 2011 to address a number of other questions related to the lipid composition and stress responses of crop and model plants. A German graduate student, Kathleen Clauss, visited our lab in late 2009 to perform lipid analysis, and members of our lab were co-authors on her paper about the metabolic effects of over-expression of an enzyme alteration aimed at improving rapeseed quality (Clauss et al., 2011). In collaboration with Xuemin Wang's lab in St. Louis, we analyzed the effect of a lipid (acyl) hydrolase on lipid composition, while our collaborators determined that the enzyme affects cellulose content and cell elongation (Li et al., 2011). We also analyzed lipid in phospholipase-deficient plants with increased tolerance to aluminum (Zhao et al., 2011). With members of Harold Trick's group, we analyzed lipid changes in soy during seed aging, testing the effects of suppression of a phospholipase that enhances seed viability (Lee et al., 2011). Additionally we used mass spectometry-based lipid analysis to examine lipid changes in pathogenic yeast as a function of biofilm formation (Lattif et al., 2011). PARTICIPANTS: PI: Ruth Welti Technician, programmer(s): Mary R Roth, Pamela Tamura, Gail Ragan Postdoctoral trainee: Sunitha Shiva, Thilani Samarakoon Graduate Students: Danny Vu Undergraduate students: Sam Honey, Charles Roach, Morgan Armbruster, Allison McKiearnan, Kaleb Lowe, Neema Prakash Collaborators: Bill Bockus, Kansas State University; Kent Chapman, University of North Texas; Gary Gadbury, Kansas State University; Mahmoud Ghannoum, Case Western Reserve University; Weiqi Li, Kunming Institute, PRC; Gerald Lushington, University of Kansas; Jyoti Shah, University of North Texas; Kathrin Schrick, Kansas State University; Dieter Strack, Leibniz Institute of Plant Biochemistry, Halle, Germany; Lloyd Sumner, Samuel Roberts Noble Foundation; Harold Trick, Kansas State University, Xuemin Wang, Danforth Plant Science Center and University of Missouri-St. Louis, St. Louis, MO; Todd Williams, University of Kansas Training opportunities: The postdoctoral trainees, the graduate student, and undergraduate students received training through their research involvement. Danny Vu and Sunitha Shiva presented posters at the Gordon Research Conference on Plant Lipids (Galveston, TX) and at a meeting at the University of Nebraska. Ruth Welti had twice weekly meetings with the undergraduates students throughout the summer. Welti presented the work in seminars at University of Iowa, Dept. of Anatomy and Cell Biology and University of Missouri, Interdisciplinary Plant Group. She also gave a talk at the KSU Functional Genomics Consortium Spring Symposium. TARGET AUDIENCES: Plant scientists; lipid researchers; stress biologists; people interested in crop improvement and sustainability. In the long term, farmers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
One outcome of our work is the publication of results in refereed journals. In 2011, on a fee-for-service basis, the Kansas Lipidomics Research Center continued to offer its lipid profiling capabilities to researchers seeking to identify the function of plant lipid metabolizing and lipid signaling genes. The researchers using the KLRC are located around the world. The long-term goal of "Lipidomics" is to understand how cellular lipids and their metabolites interact to produce and maintain complex cell membranes and to regulate organismal functions. We are using lipid profiling data in collaboration with Xuemin Wang (University of Missouri-St.Louis) and Jyoti Shah (University of North Texas) to identify and manipulate steps in membrane lipid metabolism to improve plant stress tolerance, product quality, and productivity.

Publications

  • Zhao, J., Wang, C., Welti, R., Bedair, M., Sumner, L., Baxter, I., and Wang, X. (2011). Suppression of phospholipase Dγs confers increased aluminum resistance in Arabidopsis thaliana. PLoS One. In press.
  • Clauss, K., von Roepenack-Lahaye, E., Boettcher, C., Roth, M.R., Welti, R., Erban, A., Kopka, J., Scheel, D., Milkowski, C., and Strack, D. (2011). Overexpression of sinapine esterase BnSCE3 in Brassica napus seeds triggers global changes in seed metabolism. Plant Physiol. 155, 1127-1145.
  • Lattif, A.A., Mukherjee, P.K., Chandra, J., Roth, M.R., Welti, R., Rouabhia, M., and Ghannoum, M.A. (2011). Lipidomics of Candida albicans biofilms reveals phase-dependent production of phospholipid molecular classes and role for lipid rafts in biofilm formation. Microbiology. 157, 3232-3242
  • Lee, J., Welti, R., Roth, M., Schapaugh, W.T., Li, J., and Trick, H. (2011). Enhanced seed viability and lipid compositional changes during natural aging by suppressing phospholipase Dα in soybean seed. Plant Biotechnol. J. In press. DOI: 10.1111/j.1467-7652.2011.00650.x PMID: 21895945
  • Li, M., Bahn, S.C., Guo, L., Musgrave, W., Berg, H., Welti, R., and Wang, X. (2011). Patatin-related phospholipase pPLAIIIβ-induced changes in lipid metabolism alter cellulose content and cell elongation in Arabidopsis. Plant Cell. 23, 1107-1123.
  • Schrick, K., Shiva, S., Arpin, J., Delimont, N., Isaac, G., Tamura, P., and Welti, R. (2011). Steryl glucoside and acyl steryl glucoside analysis of Arabidopsis seeds by electrospray ionization tandem mass spectrometry. Lipids. In press. PMID: 21830156
  • Shiva, S.*, Vu, H.S.* (*equal contributions), Roth, M.R., Zhou, Z., Marepally, S.R., Nune, D.S., Lushington, G.H., Visvanathan, M., and Welti, R. (2011). Lipidomic analysis of plant membrane lipids by direct infusion tandem mass spectrometry. In Plant Lipid Signaling Protocols, Methods in Molecular Biology. Ed. Teun Munnik and Ingo Heilmann. Humana Press, New York, NY. In press.
  • Vu, H.S., Tamura, P., Galeva, N.A., Chaturvedi, R., Williams, T.D., Wang, X., Shah, J., and Welti, R. (2011). Direct infusion mass spectrometry of oxylipin-containing Arabidopsis thaliana membrane lipids reveals varied patterns in different stress responses. Plant Physiol. In press. PMID: 22086419
  • Zhou, Z., Marepally, S.R., Nune, D.S., Pallakollu, P., Ragan, G., Roth, M.R., Wang, L., Lushington, G.H., Visvanathan, M., and Welti, R. (2011). LipidomeDB Data Calculation Environment: Online processing of direct-infusion mass spectral data for lipid profiles. Lipids. 46, 879-884.