Source: KANSAS STATE UNIV submitted to
DEVELOPMENT OF NOVEL STRATEGIES TO IMPROVE TOMATO THERMOTOLERANCE
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
1003429
Grant No.
(N/A)
Project No.
KS00-0084-HA
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2014
Project End Date
Sep 30, 2019
Grant Year
(N/A)
Project Director
Park, SU.
Recipient Organization
KANSAS STATE UNIV
(N/A)
MANHATTAN,KS 66506
Performing Department
Horticulture & Forestry
Non Technical Summary
Crops will experience increased heat stress with a projected global average surface temperature increase of 2.0-4.50C by the end of this century. High temperatures, often associated with drought, are major production constraints in agriculture. Climate change scenarios predict increased temperature and moisture stress and thus increased significant economic impact on tomato production in the most tomato producing regions of the world including the US. Therefore, development of heat tolerant tomato cultivars would be extremely valuable in maintaining production capacities to deal with the predicted global climatic changes. Unfortunately, few insights have been made regarding which genes and gene networks are involved in regulating heat stress tolerance of tomato. Furthermore, while various signaling networks regulate plant responses to heat stress, no mechanistic insights unifying these diverse processes have been made. We first discovered that Arabidopsis monothiol glutaredoxin, AtGRXS17, plays an essential role in redox signaling to mediate thermotolerance, and monothiol GRXS17 is conserved across species including both dicots and monocots. AtGRXS17 expression was induced by elevated temperatures and the protein appeared to translocate from the cytoplasm into the nucleus during a heat shock. Furthermore, our loss- and gain-of-function studies of GRXS17 in Arabidopsis indicate that GRXS17 is tightly linked with plant thermotolerance. Using GRXS17 loss- and gain-of-function transgenic tomato lines, we show that GRXS17 functions similarly in heat stress tolerance. Our goals are to define more precisely role of the GRXS17 in heat stress responses and to develop a breeding strategy to increase thermotolerance via a transgenic (cisgenic) approach. The specific objectives are proposed: 1) Determine the effects of GRXS17 expression on the thermotolerance in tomato reproductive stage, which is considered as the most sensitive and critical for seed set; 2) profile the expression of genes from tissues at different developmental stages of tomato during heat stress as modulated by GRXS17; 3) characterize the regulation and post-translational modification of SlGRXS17 during heat stress; and 4) establish a breeding strategy known as cisgenesis to incorporate SlGRXS17 into elite US tomato varieties. This project builds on the key role of a regulatory protein in the complex processes of thermotolerance. We also expect that our outputs will lead to greater farmer involvement in this program, and will help train a graduate student (the next generation of young molecular breeding) in preparation for future crop abiotic stress challenges.
Animal Health Component
0%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2011460101010%
2011460102020%
2011460103020%
2011460104050%
Goals / Objectives
To elucidate the mechanisms of glutaredoxin-mediated heat tolerance in tomato and to translate this knowledge into biotechnology tools for breeders to enhance heat tolerance in major crops species.
Project Methods
Objective 1: Tomato plants (Solanum lycopersicum L.) of two cultivars, Hazera 3017 (heat sensitive) and Hazera 3042 (heat tolerant) will be grown together with AtGRXS17 over-expressing Rubion under two temperature-controlled greenhouses at the KSU. They will be cultivated in 3L pots filled with Metro-Mix 700. Plants will be regularly watered to field capacity. The temperature of the greenhouse will be maintained within day/night control temperature 260C/220C, day length of 13-14h. The morphology of the reproductive organs and pollen number in flowering stage will be investigated in response to high temperature at anthesis in transgenic tomato. Rubion grows well in a greenhouse at 260C in the daytime and at 220C at night (260C/220C) as a normal condition. However, when plants are exposed to more than 6 h of high (430C) temperature or 10 d of 320C/260C temperature at anthesis, pollen numbers, fertility and morphology of the reproductive organs are significantly affected. Thus, under 2 different temperature regimes, morphological traits (anther length and width, apical and basal pore lengths, apical pore area, and stigma and pistil length, and pollen tube length), pollen number and fertility will be evaluated. Objective 2: Tomato plants of two cultivars, Hazera 3017 and Hazera 3042 including Rubion (heat sensitive) vector controls and Rubion expressing AtGRXS17 with a single gene copy will be cultivated under controlled conditions in the greenhouse [26/220C (day/night ±10C) under 12 h supplemental light] and used for genome-wide transcriptome profiling analysis. The Affymetrix tomato genome micorarray will be utilized for this analysis (http://www.affymetrix.com/products_services/arrays/specific/tomato.affx). This GeneChip® was designed specifically to monitor gene expression in tomato based on the most current version of the genome annotation. The comprehensive array consists of over 10,000 tomato probe sets to evaluate 9,200 transcripts. In two temperature-controlled greenhouses at the KSU, a gain-of-function AtGRXS17-expressing tomato, vector control and wild-types (Hazera 3017 and Hazera 3042) will be grown in 3L pots filled with Metro-Mix 700. Plants will be regularly watered to field capacity. In one of the greenhouses, the first sampling (the second fully-expanded leaf from tomato plants) will be at 4 weeks after planting for genome-wide transcriptome profiling analysis at vegetative stage. The next sampling time point will be H+1, 1 d after heat stress treatment; H+2, 2 d after heat stress treatment; and H+4, 4 d after heat stress treatment during 6 days heat stress treatment [380C/280C (day/night) for 3 days and 420C/320C after 3 days, day length of 14 h]. At the flowering stage in the other greenhouse, the sampling (microspores) will be at 6 h after heat stress treatment (430C) to flower bud (-1 d at anthesis, corresponding to microspore developmental stages). Tomato plants will produce flowers continuously for the next 3 months. To obtain enough biological material for the molecular analyses, microspores will be collected during two different spring seasons. Tomato tissue samples will be collected and frozen in liquid nitrogen followed by -800C storage. During the heat treatment, to avoid drought stress and wilting, plants will be regularly saturated with water. Three biological replicates will be used for comparison to eliminate possibly misleading results due to individual differences. qRT-PCR will be conducted to guarantee the reliability of the microarray data. RNA extraction, microarray hybridization, and scanning: Total RNA will be extracted and purified from different types of lines using TRIZOL (Invitrogen) and RNeasy column (Qiagen) according to the protocol. cDNAs will be synthesized using Superscript III RT (Invitrogen) and purified by Affy cDNA purification kit (Affymetrix). Probes will anneal to target cDNAs, and arrays will be washed by SSPE buffer and MES buffer. After removing the cocktail and staining, the chips will be scanned according to Affymetrix protocol. Data acquisition, filtering, and processing: Raw image data will be collected and normalized for intra and inter array biases using a lowess regression and quantile normalization method, respectively. Primary analysis of data will include initial comparisons of normal/treated arrays with mutant/wildtype samples. The DAnTE program will be used for this analysis. This will be done in a pair-wise scheme to identify genes differentially expressed between normal and mutant/treated conditions using a Student's t test. To control for false positives, we will use adjusted P values as determined by the Benjamini and Hochberg's FDR (False Discovery Rate). For secondary analyses, we will utilize an ANOVA mixed model to determine the extent to which each condition or treatment has a direct or combined synergistic effect on target gene expression. This model defines each mutated and/or heat stress tolerant/susceptible status as a variable term and will distinguish if genes have a differential expression in either condition and by also incorporating interaction terms, if combinations of conditions are synergistic. Explicitly, we will determine which genes have a statistically significant expression change due to the presence of both variables (heat stress tolerance and gene alteration), as opposed to heat tolerance specific or mutation specific (artifacts of transfections or developmental perturbance) expression responses. Once our ideal target gene lists are identified, we will utilize gene network building software (specific format TBD) to determine genes which have overlap in and/or intersect with each condition. Objective 3: To further determine if the nuclear-localized GRXS17 is required for heat stress tolerance, an HIV Rev NES (nuclear export signal) sequence (LQLPPLERLTL) and the NES mutant sequence (LQAPPAERATL) (the third Leu is changed to Ala) will be added at the C-termini of GFP-AtGRXS17. All constructs (35S-GFP-AtGRXS17, 35S-GFP-AtGRXS17-NES, and 35S-GFP-AtGRXS17-NESmut) will be transformed into an AtGRXS17 T-DNA insertion Arabidopsis line (atgrxs17 KO). We will examine the sub-cellular localization of GFP-AtGRXS17, GFP-AtGRXS17-NES, and GFP-AtGRXS17-NESmut in atgrxs17 KO line with or without heat treatments. The next step is to test those transgenic plants expressing AtGRXS17 constructs in comparison to atgrxs17 KO plants under heat stress. Multiple parameters (morphological, physiological, and biochemical phenotypes, and heat responsive gene expression) will be measured. These experiments will allow us to determine if the nuclear-targeting of AtGRXS17 is required for its function in thermotolerance. Objective 4: SlGRXS17 was recently cloned and is available for cisgenic tomato transformation. Rubion and a popular, but heat sensitive tomato cultivar with high transformability will be selected for generation of cisgenic lines via Agrobacterium-mediated transformation using hypocotyl and cotyledon as previously established in Park laboratory. We will construct a tomato native transformation vector containing SlGRXS17. A native SlGRXS17 promoter will be replaced with tomato LAT59 promoter, and the 25-bp right and left border of Ti plasmids will be replaced by plant-derived transfer DNA (P-DNA) sequences. To date, co-transformation to eliminate antibiotic selection markers remains the simplest strategy, followed by segregation of the marker away from the cisgene. We will co-inoculate tomato callus with two Agrobacterium strains (LBA4404 and EHA105), each containing genes of interest or selection marker. We will test the segregation of the trait using standard breeding techniques for marker free cisgenic tomato in T1 progenies and immediately characterize the lines via RT-PCR (Reverse Transcriptase-PCR) and northern analysis. There is a possibility that random insertion of the cisgene will occasionally disrupt an important gene.

Progress 10/01/14 to 09/30/19

Outputs
Target Audience:Our findings from the project were presented (18 oral/poster presentations) in several professional societies, including the American Society of Plant Biologists annual meeting, World Congress SIVB meeting, and Annual Maize Genetics Conference meeting, Fungal Genetics Conference meeting, and International Rice Blast Conference meeting. Several presentations were also provided for undergraduate and graduate students to share our research outcomes. Furthermore, new technologies about our heat stress tolerance crops were shared with farmers and producers in the US. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Training activities: Three graduate students (the next generation of young molecular breeding experts), one undergraduate student, and one research technician were trained by this project. Professional development: Our findings from the project were presented in several professional societies, including the American Society of Plant Biologists annual meeting, World Congress SIVB meeting, and Annual Maize Genetics Conference meeting, Fungal Genetics Conference meeting, and International Rice Blast Conference meeting. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Heat stress is a major factor limiting crop growth and productivity. An inevitable consequence of heat stress is the accumulation of reactive oxygen species (ROS), which leads to oxidative damage and can have devastating consequences on crop productivity. Therefore, ROS levels must be regulated in plants through the coordination of ROS production and scavenging to manage oxidative damage while maintaining ROS-mediated signaling. Though various signaling networks regulate plant responses to heat stress, the mechanisms regulating and unifying these diverse biological processes are largely unknown. This project was to understand the mechanisms of glutaredoxin-mediated heat tolerance in tomato, to develop genetically engineered heat tolerant tomato and to apply this knowledge for further enhancing heat tolerance in major other crops species, including soybean, rice and corn. We have published extensively on the glutaredoxin-mediated heat tolerance in tomato and has logged significant progress in unraveling the gene function. Furthermore, numerous transgenics and research tools have been generated by activities of this project, which were publicly accessible to the crop improvement community. The project was also the foundation for achieving the aim of the development of tomato plants with enhanced heat stress tolerance, contributing to ameliorate the consequences of future weather disasters that are likely to increase in frequency due to anticipated climatic changes and having significant potential to impact tomato production in both the near term and long term future. The results of our experiments were published on the fact that ectopic expression of a glutaredoxin S17 (GRXS17) gene in tomato plant modulates ROS accumulation and confers tolerance to heat stress without causing yield penalty. We have also demonstrated that GRXS17-expressing tomato plants show enhanced tolerance to chilling stress. A recent study showed that ectopic expression of GRXS17 in tomato enhanced tolerance to drought and oxidative stress, suggesting a general means of modulating multiple abiotic stresses (heat, chilling, and drought) in a variety of crops as well as tomato. In addition, we have showed that GRXS17-expressing corn plants display more tolerance to heat stress in reproductive and grain-filling stage of corn and increase yield compared to wild-type plants in both greenhouse and field conditions. Furthermore, GRXS17-expressing corn plants conferred more tolerance to drought stress in tasseling, silking and pollination stage of corn and dramatically increased yield compared to wild-type plants in both greenhouse and field conditions. Our findings demonstrate an alternative strategy to engineer multiple stress tolerance without adverse effects on growth and yield across different crop species in a warming global environment.

Publications

  • Type: Journal Articles Status: Published Year Published: 2019 Citation: B-C. Kang, Q. Wu, S.A. Sprague, S.H. Park, F.F. White, S-J. Bae, K. Kim, J-S. Han (2019) Ectopic overexpression of an Arabidopsis monothiol glutaredoxin AtGRXS17 affects floral development and enhances tolerance to heat stress in chrysanthemum (Chrysanthemum morifolium Ramat.). Environmental and Experimental Botany. 167: 103864
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Z. Peng, Y. Hu, J. Zhang, J.C. Huguet-Tapia, A.K. Block, S.H. Park, S. Sapkota, Z. Liu, S. Liu, and F.F. White (2019) Xanthomonas translucens commandeers the host rate-limiting step in ABA biosynthesis for disease susceptibility. Proc. Natl. Acad. Sci. USA. 116: 20938-20946
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: J. Zhao, P. Li, C.M. Motes, S.H. Park, and K.D. Hirschi (2015) CHX14 is a plasma membrane K-efflux transporter that regulates K+ redistribution in Arabidopsis thaliana. Plant Cell & Environment. 38: 2223-2238
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: N. Driedonks, J. Xu, J.L. Peters, S.H. Park, and I. Rieu (2015) Multi-level interactions between heat shock factors, heat shock proteins and the redox system regulate acclimation to heat. Frontiers in Plant Science. 6: 999
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Y. Hu, Q. Wu, S.A. Sprague, J. Park, M. Oh, C.B. Rajashekar, H. Koiwa, P. Nakata, N. Cheng, K.D. Hirschi, F.F. White, and S.H. Park (2015) Tomato expressing Arabidopsis glutaredoxin gene AtGRXS17 confers tolerance to chilling stress via modulating cold responsive components. Horticulture Research. 2: 15051
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: C. He, J. Zheng, Y. Du, S.H. Park, F.F. White, G. Wang, and S. Liu (2019) Time-series analysis of maize transcriptomes under drought stress. Annual Maize Genetics Conference  Maize GDB, March/2019. Saint Louis, MO
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: T.M. Temang, S.A. Sprague, T. Kakeshpour, T. Steiner, S. Liu, F.F. White, and S.H. Park (2019) Ectopic expression of a heterologous glutaredoxin enhances tolerance to multiple abiotic stressors and grain yield in field grown maize. Annual Maize Genetics Conference  Maize GDB, March/2019. Saint Louis, MO
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: B. Valent, E. Oliveira-Garcia1, G. Lin, M. Dalby, S. Liu, J. Park, and S.H. Park (2019) From mobile genes to mobile proteins: effectors in Magnaporthe oryzae. The 30th Fungal Genetics Conference, March/2019. Pacific Grove, CA
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: E. Oliveira-Garcia1, Ma. Martin-Urdiroz, C. Rodriguez-Herrero, N.J. Talbot, J. Park, S.H. Park, and B. Valent (2019) Clathrin-dependent endocytosis mediates internalization of Magnaporthe oryzae effectors into rice cells. The 30th Fungal Genetics Conference, March/2019. Pacific Grove, CA
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: B. Valent, E. Oliveira-Garcia, G. Lin, M. Dalby, S. Liu, S.H. Park, and N.J. Talbot (2019) Mobile effector proteins encoded by mobile genes in the blast fungus. The 8th International Rice Blast Conference (IRBC), May/2019. Chengdu, China
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: G. Lin, Y. Liu, T.M. Temang*, J. Zheng, H. Le, C. He, J. Fu, M-J. Cho, S.H. Park, H. Wei, F.F. White, Y. Liu, G. Wang, and S. Liu (2019) Genetic and Genomic Resources for Maize Transformation. Plant Biology 2019, August/2019. San Jose, CA
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: T.M. Temang, S.A. Sprague, T. Kakeshpour, T. Steiner, S. Liu, F.F. White, and S.H. Park (2019) Ectopic expression of a heterologous glutaredoxin enhances tolerance to multiple abiotic stressors and grain yield in field grown maize. 2019 World Congress SIVB, June/2019. Tampa, FL


Progress 10/01/17 to 09/30/18

Outputs
Target Audience:Our findings from the project were presented in the 2018 World Congress SIVB annual meeting and International Congress of Plant Pathology (ICPP) annual meeting, respectivelly. Several presentations were also provided for undergraduate and graduate students to share our research outcomes. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Three graduate students and one research technician were trained by this project. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?Further molecular, physiological, and phenotypic studies using these Slgrxs CRISPR tomato mutant lines will be completed.

Impacts
What was accomplished under these goals? To understand the underlying mechanisms of how Solanum lycopersicum class II glutaredoxins (SlGRXs) coordinate with other proteins to regulate the tomato development and abiotic stress response, we generated transgenic tomato plants carrying targeted mutations of class II SlGRXs (SlGRXS14, S15, S16, and S17), which may be involved in abiotic stress adaptation, using a multiplex bacterial clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system. CRISPR/Cas9 was able to successfully edit all 4 target genes simultaneously and introduce quadruple mutant lines. These different combinations of single, double, triple and quadruple mutant lines of class II GRXs will provide a powerful tool to study functions and interactions of each individual GRXS14, 15, 16, and 17.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: T.M. Temang, J. Park, T. Kakeshpour, B. Valent, Y. Jia, G-L. Wang, and S.H. Park (2018) Development of selectable marker-free cisgenic rice plants expressing a blast resistance gene Pi9. 2018 World Congress SIVB, June/2018. Saint Louis, MO
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: T. Kakeshpour, Q. Wu, T.M. Tamang, J. Park, and S.H. Park (2018) Multiplex genome editing of class II glutaredoxins in Solanum lycopersicum via a CRISPR/Cas9 system. 2018 World Congress SIVB, June/2018. Saint Louis, MO
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: S.A. Sprague, T.M. Temang, T. Steiner*, N. Cheng, K.D. Hirschi, S.V.K. Jagadish, F.F. White, and S.H. Park (2018) Expression of AtGRXS17 in Maize Increases Heat Stress Tolerance. 2018 World Congress SIVB, June/2018. Saint Louis, MO
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Z. Peng, Y. Hu, J. Zhang, S.H. Park, Z. Liu, S. Liu, and F.F. White (2018) TAL effector targets abscisic acid biosynthesis pathway for disease susceptibility in bacterial leaf streak of wheat. International Congress of Plant Pathology (ICPP), July/2018. Boston, MA


Progress 10/01/16 to 09/30/17

Outputs
Target Audience:Our findings from the project were presented in the American Society of Plant Biologists annual meeting. Several presentations were also provided for undergraduate and graduate students to share our research outcomes. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Training activities: Three graduate students and one research technician were trained by this project. Professional development: Our findings from the project were presented in the American Society of Plant Biologists annual meeting. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The monothiol glutaredoxin AtGRXS17 from Arabidopsis provides heat and drought stress tolerance in yeast, Arabidopsis, and tomato. In recent study, we investigated how Silencing of OsGRXS17 in rice also influences drought stress response and tolerance and affects plant growth and development. We found that RNAi-mediated suppression of Oryza sativa GRXS17 (OsGRXS17) improved drought tolerance in rice without adverse effects on growth and development. Gene expression studies showed that OsGRXS17 was present throughout the plant and that transcript abundance increased in response to drought stress and abscisic acid (ABA) treatment. Localization studies, utilizing GFP-OsGRXS17 fusion proteins, indicated that OsGRXS17 resides in both the cytoplasm and the nuclear envelope. Under drought stress conditions, rice plants with reduced OsGRXS17 expression showed lower rates of water loss and stomatal conductance, higher relative water content, and enhanced survival compared to wild-type controls. Further characterization of the OsGRXS17 down-regulated plants revealed an elevation in H2O2 production within the guard cells, increased sensitivity to ABA, and a reduction in stomatal apertures. The findings demonstrate a critical link between OsGRXS17, the modulation of guard cell H2O2 concentrations, and stomatal closure, expanding our understanding of the mechanisms governing plant responses to drought.

Publications

  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Q. Wu, Y. Hu, S.A. Sprague, T. Kakeshpour, J. Park, P. Nakata, N. Cheng, K.D. Hirschi, F.F. White, and S.H. Park (2017) Expression of a monothiol glutaredoxin, AtGRXS17, in tomato (Solanum lycopersicum) enhances drought tolerance. Biochemical and Biophysical Research Communications. 491: 1034-1039
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: H. Yu, J. Yang, Y. Shi, J. Donelson, S.M. Thompson, S.A. Sprague, T. Roshan, D. Wang, J. Liu, S.H. Park, P.A. Nakata, E.L. Connolly, K.D. Hirschi, M.A. Grusak, and N. Cheng (2017) Arabidopsis Glutaredoxin S17 Contributes to Vegetative Growth, Mineral Accumulation, and Redox Balance during Iron Deficiency. Frontiers in Plant Science. 8: 1024
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Q. Wu, J. Yang, N. Cheng, K.D. Hirschi, F.F. White, and S.H. Park (2017) Glutaredoxins in plant development, abiotic stress response, and iron homeostasis: From model organisms to crops. Environmental and Experimental Botany. 139: 91-98
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: B. Valent, E. Oliveira-Garcia, M. Yi, P. Migeon, M. Dalby, S. Sprague, J. Park, and S.H. Park (2017) How the blast fungus hijacks living rice cells. Plant Biology 2017, June/2017. Honolulu, HI
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Y. Hu, Q. Wu, Z. Peng, S.A. Sprague, W. Wang, J. Park, E. Akhunov, K.S.V. Jagadish, P. Nakata, N. Cheng, K.D. Hirschi, F.F. White, and S.H. Park (2017) Silencing of OsGRXS17 in rice improves drought stress tolerance by modulating ROS accumulation and stomatal closure. Scientific Reports. 7: 15950


Progress 10/01/15 to 09/30/16

Outputs
Target Audience:Our findings from the project were presented in the American Society of Plant Biologists annual meeting. Several presentations were also provided for undergraduate and graduate students to share our research outcomes. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Training activities: One graduate student, one undergraduate student, and one research technician were trained by this project. Professional development: Our findings from the project were presented in the American Society of Plant Biologists annual meeting. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The monothiol glutaredoxin AtGRXS17 from Arabidopsis provides thermotolerance in yeast, Arabidopsis, and tomato. In recent study, we investigated how AtGRXS17 also influences drought stress response and tolerance in tomato and affects plant growth and development. We found that tomato expressing AtGRXS17 conferred tolerance to drought and oxidative stress without adverse effects on growth and development. AtGRXS17-expressing tomato plants retained twice the shoot water content as compared to wild-type plants under water limiting conditions. Enhanced drought tolerance correlated with elevated levels of endogenous abscisic acid (ABA)-responsive element binding protein 1 (SlAREB1), which mediates ABA-dependent drought tolerance. Further, AtGRXS17-expressing plants displayed longer primary roots than wild-type plants and showed increased expression of the antioxidant enzyme catalase 1 (SlCAT1) upon treatment with the pro-oxidant herbicide methyl viologen. These findings indicate that ectopic expression of AtGRXS17 impacts drought stress pathways and may provide a general approach to improve tolerance to drought stress in agriculturally important crop species. We are preparing a manuscript to publish the results in one of the peer-reviewed journals.

Publications

  • Type: Journal Articles Status: Published Year Published: 2016 Citation: P. Li, G. Zhang, N. Gonzales, Y. Guo, H. Hu, S.H. Park, and J. Zhao (2016) Ca2+-and diurnal rhythm-regulated Na+/Ca2+ exchanger AtNCL affects flowering time and auxin signaling in Arabidopsis. Plant Cell & Environment. 39: 377392
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Qingyu Wu, S.H. Park, M.B. Kirkham, and Kimberly A. Williams. (2016) Transcriptome analysis reveals potential mechanisms for inhibition of intumescence development by UV radiation in tomato. Environmental and Experimental Botany. 134: 130-140
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Florian M�ller, Jiemeng Xu, Lieke Kristensen, Mieke Wolters-Arts, Peter F. M. de Groot, Stuart Y. Jansma, Celestina Mariani, S.H. Park, and Ivo Rieu. (2016) High-Temperature-Induced Defects in Tomato (Solanum lycopersicum) Anther and Pollen Development Are Associated with Reduced Expression of B-Class Floral Patterning Genes. PLOS ONE. e0167614
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: S.A. Sprague, Y. Hu, Q. Wu, J. Park, N. Cheng, K.D. Hirschi, F.F. White, S.H. Park (2016) Ectopic expression of Arabidopsis glutaredoxin gene AtGRXS17 in maize (Zea mays) enhances tolerance to heat stress. Plant Biology 2016, July/2016. Austin, TX


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

Outputs
Target Audience:A presentation was provided for undergraduate and graduate students to share our research outcomes. Two poster presentations in a professional society, American Society of Plant Biologists annual meeting (Portland, Oregon), were given. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Training activities: Two graduate students, one undergraduate student, and one research technician were trained by this project. Professional development: Our findings from the project were presented in the American Society of Plant Biologists annual meeting. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?Our findings demonstrate that genetically engineered tomato plants expressing AtGRXS17 can enhance extreme temperature stress tolerance and suggest a genetic engineering strategy to improve heat and chilling tolerance without yield penalty across different crop species. As a proof of concept, we will further evaluate whether corn plants expressing AtGRXS17 can also enhance heat and chilling stress tolerance.

Impacts
What was accomplished under these goals? An inevitable consequence of heat or chilling stress is the accumulation of reactive oxygen species (ROS), which is one of the major factors leading to oxidative damage. Therefore, ROS levels must be regulated in plants through the coordination of ROS production and scavenging to manage oxidative damage while maintaining ROS-mediated signaling. We have focused on the function of the Arabidopsis GRX gene AtGRXS17 in mediating redox changes due to heat stress of plants. In recent study, we investigated how AtGRXS17 influences chilling stress response and tolerance in tomato and affects plant growth and development to better understand the functional mechanisms of glutaredoxin-mediated multiple abiotic stress tolerance in tomato. We found that tomato expressing AtGRXS17 conferred tolerance to chilling stress as well as heat stresswithout adverse effects on growth and development. AtGRXS17-expressing tomato plants displayed lower ion leakage, higher maximal photochemical efficiency of photosystem II (Fv/Fm) and increased accumulation of soluble sugar compared with wild-type plants after the chilling stress challenge. Furthermore, chilling tolerance was correlated with increased antioxidant enzyme activities and reduced H2O2 accumulation. At the same time, temporal expression patterns of the endogenous C-repeat/DRE Binding Factor 1 (SlCBF1) and CBF mediated-cold regulated (COR) genes were not altered in AtGRXS17-expressing plants when compared to wild-type plants, and proline concentrations remained unchanged relative to wild-type plants under chilling stress. GFP-AtGRXS17 fusion proteins, which were initially localized in the cytoplasm, migrated into the nucleus during chilling stress, reflecting a possible role of AtGRXS17 in nuclear signaling of chilling stress responses. Our findings demonstrated that genetically engineered tomato plants expressing AtGRXS17 could enhance chilling tolerance and suggested a genetic engineering strategy to improve chilling tolerance without yield penalty across different crop species. We have published the results in one of the peer-reviewed journals, and numerous transgenics and research tools have been generated by activities of this work, which were publicly accessible to the plant biology/crop improvement community.

Publications

  • Type: Journal Articles Status: Published Year Published: 2014 Citation: M. Park, J-S. Han, Y. Ahn, J. Kim, H. Lee, Y. Jang, R. Gaxiola, K.D. Hirschi, and S.H. Park. (2014) Ectopic expression of Arabidopsis H+-pyrophosphatase AVP1 enhances drought resistance in bottle gourd (Lagenaria siceraria Standl.). Plant Cell, Tissue and Organ Culture (PCTOC): Journal of Plant Biotechnology. 118: 383-389
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: J-S. Han, K. Park, S. Jeon, S.H. Park, A.H. Naing, and C. Kim (2015) Assessments of salt tolerance in a bottle gourd line expressing the Arabidopsis H+-pyrophosphatase AVP1 gene and in a watermelon plant grafted onto a transgenic bottle gourd rootstock. Plant Breeding. 134: 233-238
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: S.A. Sprague, Q. Wu, Y. Hu, D. Park, N. Cheng, K.D. Hirschi, F.F. White, and S.H. Park (2014) Ectopic expression of AtGRXS17, an Arabidopsis glutaredoxin, enhances drought resistance in tomato Plant Biology 2014, Portland, OR
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Y. Hu, Q. Wu, S.A. Sprague, J. Park, M. Oh, C. B. Rajashekar, H. Koiwa, P.A. Nakata, N. Cheng, K.D. Hirschi, F.F. White, and S.H. Park (2014) Ectopic expression of Arabidopsis glutaredoxin gene AtGRXS17 in tomato (Solanum lycopersicum) confers tolerance to chilling stress. Plant Biology 2014, Portland, OR
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: M. Montero-Ast�a, D. Rotenberg, A. Leach, B. Schneweis, S.H. Park, J. Park, T.L. German, and A.E. Whitfield. (2014) Disruption of vector transmission by a plant-expressed viral glycoprotein. Molecular Plant-Microbe Interactions. 27: 296-304
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: W. Lim, R. Miller, J. Park, and S.H. Park. (2014) Consumer sensory analysis of high flavonoid transgenic tomatoes. Journal of Food Science. 79: S1212-S1217