Source: SOUTH DAKOTA STATE UNIVERSITY submitted to NRP
A GENETICS AND GENOMICS PROGRAM AIMING TO IMPROVE SUSTAINABILITY OF WHEAT PRODUCTION FOR FOOD AND BIOFUELS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0220507
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Sep 1, 2009
Project End Date
Sep 30, 2014
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
SOUTH DAKOTA STATE UNIVERSITY
PO BOX 2275A
BROOKINGS,SD 57007
Performing Department
Biology & Microbiology
Non Technical Summary
Wheat is the most widely-cultivated crop, occupying 17% of all crop area, topping trade value among all the crops, therefore, playing an important role in world food security. To meet human needs by 2050, grain production must increase at an annual rate of 2%. Due to the changing climatic conditions and shrinkage of arable land, wheat production is facing numerous challenges, among which drought, heat and diseases are most significant. Genomics, including marker genotyping, genome mapping, genome sequencing, transcriptome profiling and gene silencing is believed as a general mechanism to identify the genes underlying the complicated traits such as biotic and abiotic stress tolerance. Current wheat genomics resources include a collection of >1,000,000 expressed sequence tags (ESTs), ~16,500 markers, high density linkage maps and deletion bin maps and the BAC libraries. The physical maps of wheat chromosomes and the D genome of Aegilops tauschii are under construction; single nucleotide polymorphism (SNP) markers are under development; and whole genome sequencing is under discussion. Taking the advantages of wheat genomics, I propose to construct exotic genetic libraries for dissection of the complex traits and discovery and cloning of quantitative trait loci (QTL) and to develop mutagenesis populations for mutant development. Shattering was the first trait selected against in wheat domestication, but is still a factor of yield loss during harvest by combine. Cloning of shattering gene Br2 will provide a window to understand the molecular mechanism of shattering and help develop strategies to prevent shattering and avoid the introgression of shattering genes as linkage drags. Epidermal cells are the first to perceive the environmental signals and cuticle serves as the front line of defense against drought, heat, frost, UV, pathogens and insects. A review of current knowledge suggested that intracuticular wax plays an important role in drought tolerance by adjusting the cuticle permeability, and epicuticular wax plays important role in heat tolerance by increasing reflectability of sun light. Epidermis is composed of single layer of cells and no EST was made specifically from grass epidermis. Coupling the epidermal transcriptome profiling and VIGS will provide a high throughput approach to identify the cuticle biosynthetic and regulatory genes and lay a foundation to engineer the wheat cuticle for abiotic stress tolerance. Lignocellulosic biomass is the important resource for renewable biofuels. Lignin and derivatives impede cell wall degradation by interfering with access of hydrolytic enzymes to cellulose polymers. Hollow stem limits the biomass yield in the Triticeae grasses. Reduction of lignin by RNAi and breeding solid stem can significantly improve the biomass quality and yield.
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
2011540108025%
2031540104025%
2031540108025%
2031540108125%
Knowledge Area
203 - Plant Biological Efficiency and Abiotic Stresses Affecting Plants; 201 - Plant Genome, Genetics, and Genetic Mechanisms;

Subject Of Investigation
1540 - Hard red winter wheat;

Field Of Science
1040 - Molecular biology; 1081 - Breeding; 1080 - Genetics;
Goals / Objectives
My long-term goal is to establish an internationally recognized research program of wheat genetics and genomics aiming to improve the sustainability of wheat production for food and biofuels. My objectives are: 1) molecular genetics of wheat domestication; 2) genomics-facilitated germplasm enhancement; 3) genomics of abiotic stress (characterization of epidermal transcriptome); and 4) feedstock genomics. The expected outputs from this project will include germplasm such as introgression lines, mutants, RNA interference (RNAi) transgenic plants; molecular markers; cloned genes; graduate student training; and paper publication.
Project Methods
Objective 1. Br2 is one of major determinants of hexaploid wheat domestication and we already mapped to the long arm of chromosome 3D in Aegilops tauschii. We will finely map and isolate this shattering gene using a positional cloning approach. Its signaling pathway will be functionally documented by quantitative real time PCR (qRT-PCR) analysis of isogenic lines, and by promoter-reporter and yeast one hybrid assays. The sequence diversity and selection effect on Br2 locus will also be investigated in the Ae. tauschii and hexaploid wheat populations. Objective 2. We will construct exotic genetic libraries, in wheat varieties well adapted in South Dakota (SD), by introgression of chromosome segments from the Ae. tauschii accession showing greatest genetic dissimilarity to the D genome of hexaploid wheat to capture as much variation of this species as possible. Based on the marker genotypes of the BC2F2 populations, we will select 96 single-segment introgression lines to cover the Ae. tauschii genome. Mutagenesis populations will be developed for SD wheat and soybean by EMS treatment. Each population will consist of 1536 independent M2 plants. DNA will be isolated from them and target genes will be amplified by PCR. The mutants will be screened by Targeting Induced Local Lesions IN Genomes (TILLING). We will focus on the abiotic stress tolerance, grain quality and herbicide resistance. Objective 3. For abiotic stress, we will focus on dissecting the pathways of cuticle biosynthesis. To this end, the epidermis will be peeled for RNA isolation, from which cDNA will be synthesized and sequenced by 454 technology. The sequences will be mined for the cuticle-related genes, and special attention will be paid to the transcription factors. A sub set of the most significant candidates will be further characterized by virus induced gene silencing (VIGS). At the mean time, the small RNA and target RNA libraries will be constructed and sequenced by Solexa technology. In addition, we will isolate the wax inhibitor gene Iw1 by positional cloning. Objective 4. For feedstock genomics, we have identified 21 lignin candidate genes and developed RNAi transgenic plants for them. We will develop double RNAi lines by crossing the existing transgenic wheat. The F1 plants will be characterized by qRT-PCR and metabolite profiling to determine their lignin content and composition. In addition, we will transfer the solid stem genes from wheat into the intermediate wheatgrass by marker assisted selection. Introgression lines, libraries, mutagenesis populations and mutants developed in the SD elite varieties are important germplasm for genetic improvement of SD wheat and soybean. The double RNAi transgenic wheat and solid-stem intermediate wheatgrass will be important germplasm for Triticeae biomass crops and forages. The cloned genes can be used as perfect molecular markers for molecular breeding and for developing expression cassettes and transgenic plants. Two graduate students will be trained in plant molecular genetics/genomics through this project. The results from this project will be disseminated by paper publication and symposium presentation.

Progress 09/01/09 to 09/30/14

Outputs
Target Audience: Scientific community in general and wheat growers Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Since the project start in January of 2010, the results were disseminated through conferences, workshop and Journal publications. This includes Internattional Plant and Animal Genome conferences (2011 and 2012), International Triticeae Mapping Initiative (June 2012), NorthCentral SUNGRANT annual conferences (Jan 2012, March 2013 and March 2014), Midwestern Section Annual Meeting of Ammerican Society of Plant Biologists (March 2012), and McFadden Symposium (Sept 2014). Five papers published refereed journals. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Objective 1. Molecular Genetics of Wheat Domestication. We localized the Br2 locus for barrel type shattering in 0.008-cM interval with 9 marker loci co-segregated. While single crossovers were completely suppressed, double crossovers were recovered from the Br2 region indicating a putative inversion polymorphism between the two parental lines from two lineages of Aegilops tauschii. Genotyping additional 55 accessions showed that the two lineages are genetically isolated in the Br2 region suggesting that the inversion polymorphism may have been fixed between the two lineages. At the same time, we investigated polyploid wheat evolution including domestication using chloroplast-based phylogeny and marker genotyping and found wild emmer was involved in formation of European spelt wheat. Objective 2 Genomics-Facilitated Germplasm Enhancement. We developed EMS-mutagenesis populations in wheat cultivars Brick and Overland and soybean cultivar Surge. From the soybean mutagenesis population (M2), we recovered several interesting mutants, such as pentafolium, glabra, brown trichome, cupping leaf and small-pod, and identified one spontaneous nonglaucous mutant in Bobwhite (BW) and a reduced-wax mutant in Brick. In addition, we developed near isogenic lines for nonglaucousness in TAM110, and for very short root 1 (Vsr1) in Chinese Spring (CS) and BW. Objective 3. Genomics of Abiotic Stress. Our research under this objective was focused on cuticular wax (glaucousness) and Root development by Vsr1. The major results are summarized as follows. (1) Iw2 was localized to a 0.7-cM interval on 2DS and Iw3 to a 0.0135-cM interval on 1BS. (2) While W1 and W2 redundantly function in β-diketone biosynthesis, a combination of both functional alleles led to the β-diketone hydroxylation. Consistent with this, transcription of MAH1-9, which encodes a mid-chain alkane hydroxylase, increased seven-fold only in W1W2. (3) Elimination of β-diketones is compensated for by an increase in aldehydes and primary alcohols in the Iw NILs. Accordingly, transcription of CER4-6, which encodes an alcohol-forming fatty acyl-CoA reductase, was elevated ~100-fold in the Iw2 NIL. (4) W3, the newly discovered glaucousness locus in BW, is mapped to a position proximal to W1 on 2BS. The w3 mutant lost 99% β-diketones and highly sensitive to water withdraw treatment. (5) Vsr1 is localized in a 0.9-cM interval on 5DL and a candidate gene is identified by mapping and quantifying the transcripts for genes in the interval. It encodes a hypothetic protein containing two function unknown domains. Objective 4. Feedstock Genomics Funded by DOE through NC SUN GRANT, we are developing solid-stem Triticale as a feedstock for biofuel production. We developed first batch of solid stem winter Triticale, including seven primary lines and 68 derived lines. Our results showed that population structure exists in the winter solid-stem durum lines maintained in the National Small Grain Collections, and most of them carry incrossability genes. This is not expected and the difficulty to overcome the incompatibility was underestimated. Comparison between a pair of solid-stem and hollow-stem Triticale near isogenic lines (NILs) indicated that the linear density of internodes increased by 160% to 190% in the solid-stem line, showing great biomass yielding potential. All lignin species in all internode positions showed no significant change between the NILs, indicating the solid-stem gene may did not affect lignin content in the increased biomass.

Publications

  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Li W, Zhu H, Challa GS, Zhang ZZ. 2013. Non-additive interaction in a single locus causes a very short root phenotype in wheat. Theor Appl Genet. 126:1189-1200.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Zhang Z, Wang W, Li W. 2013. Genetic Interactions Underlying the Biosynthesis and Inhibition of ?-Diketones in Wheat and Their Impact on Glaucousness and Cuticle Permeability. PLoS ONE 8(1): e54129. doi:10.1371/journal.pone.0054129
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Wang J, Li W, Wang W. 2014. Fine mapping and metabolic and physiological characterization of the glume glaucousness inhibitor locus Iw3 derived from wild wheat. Theor Appl Genet 127:831-841.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Gornicki P, Zhu H, Wang J, Challa GS, Gill BS, Li W. The Chloroplast view of the evolution of polyploid wheats. New Phytologist 204:704-714.
  • Type: Journal Articles Status: Accepted Year Published: 2015 Citation: Zhang Z, Zhu H, Gill BS, Li W. 2014. Fine mapping and haplotyping of Br2 interval revealed genomic and population structure variation in Aegilops tauschii Coss. Theor Appl Genet (accepted).
  • Type: Other Status: Published Year Published: 2012 Citation: Challa, GS, Zhang ZZ, Li W. De novo assembly and characterization of wheat root transcriptome. International Triticeae Mapping Initiative 2012. June 25-29, Fargo, ND. P13.
  • Type: Other Status: Published Year Published: 2012 Citation: Li W, Zhu H, Wang J, Challa GS, and Gill BS. 2012. A cytoplasmic view of polyploid wheat evolution. [Abstract P0292].
  • Type: Other Status: Published Year Published: 2012 Citation: Zhang ZZ, Li W. Metabolic, physiological and molecular characterization of cuticular wax variation in wheat. 2012 Midwestern Section Annual Meeting of Ammerican Society of Plant Biologists. March 24-25, 2012. University of Nebraska-Lincoln, Lincoln, NE. [Abstract P27].
  • Type: Other Status: Published Year Published: 2012 Citation: ZZ, Wang W, Li W. Metabolic, physiological and molecular characterization of cuticular variation in wheat. International Triticeae Mapping Initiative 2012. June 25-29, Fargo, ND. [Abstract P30].
  • Type: Other Status: Published Year Published: 2012 Citation: Zhu H, Wang W, Zhang Z, Challa GS, Li W. 2012. Dominant gene interaction causes very short root phenotype in wheat. Plant and Animal Genome Conference XX [Abstract P03114].


Progress 10/01/12 to 09/30/13

Outputs
Target Audience: Plant scientist community Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Training activities: grduate training by participation in the projects. Mr. Ghana S. Challa worked on wheat transcriptomics and soybean mutant analysis. Ms Jing Wang worked on fine mapping and characterization of Iw3. How have the results been disseminated to communities of interest? Journal publication Wang J, Li W, Wang W. 2013. Fine mapping and metabolic and physiological characterization of the glume glaucousness inhibitor locus Iw3 derived from wild wheat. Theor Appl Genet (in press, doi:10.1007/s00122-014-2260-8) Conference presentations Li W, Yen Y. Develop solid-stem triticale as feedstock for biofuel production. North Central Regional Sun Grant Annual conference. March 21-23, 2012. Chicago, IL. Li W. Fine mapping of shattering gene Br2. KSRE Seminars, July 19, 2013, Kansas State University, Manhattan, KS What do you plan to do during the next reporting period to accomplish the goals? For Objective 1. Continue the map-based cloning effort and submit a manuscript. For Objective 2. Mine the genome resequence data for identification of candidate genes underlying the glabra mutations. For Objective 3. Continue the effort to isolate the Vsr1 and analyze dosage effect; characterize the nonglaucous mutants from Bobwhite and TAM110 in wheat. For Objective 4. Develop solid stem and holl stem Triticale near isogenic lines and analyze their cell wall contents.

Impacts
What was accomplished under these goals? Following is brief report of the progress made in year 2013. Objective 1. Molecular genetics of wheat domestication. We are map-based cloning shattering gene Br2. We localized it in a 0.08-cM. We sequenced the BAC contig for identifying candidate gene. Finer mapping of the recovered recombinants and genotype a collection of 57 accessions found that the two subspecies of Aegilops tauschii are polymorphic for a paracentric inversion in Br2 region. This provides a mechanism for genetic isolation of the subspecies in nature. Objective 2. Genomics-facilitated germplasm enhancement. In addition to the nonglgaucous mutant in Bibwhite and reduced glaucous mutant in Brick wheat, we identified another nonglaucous mutant from TAM110. In soybean, we resequenced genomes of Surge and trichomeless (glabra) mutants in order to identify the mutant genes. Data analysis is under way. Objective 3. Genomics of abiotic stress. Under this objective we focused on map-based cloning very short root 1 (Vsr1) gene and wax inhibitor Iw3. We are fine mapping the gene to a 0.9-cM interval, found a co-segregating marker. Using the information from Aegilops tauschii BAC contigs and scaffolds genome sequences, we are closing the gap. In another aspect, we found that VSR is under epigenetic regulation related with a single gene dosage. Related with this, we sequenced, assembled, annotated, and quantified the root transcriptomes of Chinese Spring wheat.For Iw3, We localized the locus within a 0.13-cM interval delimited by marker loci Xpsp3000 and XWL3096. Of the 53 wax candidate genes assayed, we detected transcription changes in nine genes by Iw3, down-regulation of Cer4-1 and up-regulation of other five Cer4 and three KCS2 homologs. Compared to the wild type, Iw3 eliminates β-diketone, reduces 47% primary alcohols, but increases aldehyde 400-fold and alkanes fivefold, which leads to 30% reduction of total glume wax load. Loss of the glaucousness increased cuticle permeability suggesting important role in drought sensitivity. One paper has been accepted for publication Theor Appl Genet. Objective 4. Feedstock genomics funded by DOE through SUN GRANT. We made first batch solid-stem Triticale and made more than 40 crosses between them and conventional Triticale cultivars (hollow-stem). Preliminary result from greenhouse showed solid-stem Triticale is advantageous over the hollow-stem ones in biomass yield.

Publications

  • Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Wang J, Li W, Wang W. 2014. Fine mapping and metabolic and physiological characterization of the glume glaucousness inhibitor locus Iw3 derived from wild wheat. Theor Appl Genet (in press, doi:10.1007/s00122-014-2260-8)


Progress 01/01/12 to 09/30/12

Outputs
Target Audience: Plant researchers studying abiotic stress responses. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported 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? Isolation of Br2 gene, a major determinate of wheat domestication will allow us to understand the selection process during domestication and the signaling pathways of wheat spike development. Mutants are invaluable resources for biological studies. Mutants found in this program will be used for wheat and soybean biology of the agronomic traits. Cuticular wax is critical in preventing water loss via non-stomatal evaporation. Mapping and cloning of the wax and wax-inhibitor genes will eventually lead to dissection of the wax pathways and allow us to regulate the cuticular wax to enhance wheat tolerance to drought. Also these genes will tell us their history during the domestication and modern breeding process. Triticale is used as a cover crop in Corn-Belt. Recent study showed it can be used for feedstock production without competition of land with food crops. But current cultivars were bred for grain. Development of solid-stem Triticale will hopefully lay a found for biomass-orientated breeding of this man-made crop. No molecular study on wheat root is available. The very short root phenotype presents a very unique phenomenon of genetics and physiology of plant root development. This may provide us a window for new insights of root development.

Publications

  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Li W, Zhu H, Wang J, Challa GS, and Gill BS. 2012. A cytoplasmic view of polyploid wheat evolution. [Abstract P0292]. Rawat N, Sehgal SK, Joshi A, Rothe N, Li W, and Gill BS. 2012. Diploid wheat (Triticum monococcum) as a model for gene discovery in wheat. [Abstract P0340]
  • Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: Rawat N, Kalia B, Sehgal S, Li W, and Gill BS. 2012. Molecular mapping of the brittle rachis (Br-A1) gene in Triticum timopheevii. International Triticeae Mapping Initiative 2012. June 25-29, Fargo, ND. [Abstract P29]
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Sehgal SK, Aknunov E, Li W, Kaur G, Catana V, Pillamari J, Faris JD, Reddy L, Devos KM, Rabinowicz PD, Chan A, Maiti R, Simkova H, Safar J, Dolezel J, Luo M-C, Ma Y, You FM, and Gill BS. 2012. Physical and genetic framework of chromosome 3A of bread wheat. [Abstract P0028].
  • Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: Zhang ZZ, Li W. Metabolic, physiological and molecular characterization of cuticular wax variation in wheat. 2012 Midwestern Section Annual Meeting of American Society of Plant Biologists. March 24-25, 2012. University of Nebraska-Lincoln, Lincoln, NE. [Abstract P27].
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: ZZ, Wang W, Li W. Metabolic, physiological and molecular characterization of cuticular variation in wheat. International Triticeae Mapping Initiative 2012. June 25-29, Fargo, ND. [Abstract P30].
  • Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: Zhu H, Wang W, Zhang Z, Challa GS, Li W. 2012. Dominant gene interaction causes very short root phenotype in wheat. Plant and Animal Genome Conference XX [Abstract P03114].
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Refereed Journals Li W, Zhu H, Challa GS, Zhang ZZ. 2013. Non-additive interaction in a single locus causes a very short root phenotype in wheat. Theor Appl Genet. doi:10.1007/s00122-013-2046-4. Zhang Z, Wang W, Li W. 2013. Genetic Interactions Underlying the Biosynthesis and Inhibition of ?-Diketones in Wheat and Their Impact on Glaucousness and Cuticle Permeability. PLoS ONE 8(1): e54129. doi:10.1371/journal.pone.0054129
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Challa, GS, Zhang ZZ, Li W. De novo assembly and characterization of wheat root transcriptome. International Triticeae Mapping Initiative 2012. June 25-29, Fargo, ND. P13.


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

Outputs
OUTPUTS: AD421 report In year 2011, progress has been made in my Hatch project "A genetics and genomics program aiming to improve sustainability of wheat production for food and biofuels". Following is a brief report. Objective 1. Molecular Genetics of Wheat Domestication. Markers were developed for genes in colinear region between wheat and model grasses and Br2 was mapped to a 0.08 cM interval and cosegregating with four gene markers. We are ready for chromosomal landing by screening the BAC library once the physical mapping data are publicly available. At the same time we got progress in polyploid wheat evolution by comparative analysis of common wheat Timopheevi wheat. The results showed that the B- and G- genome donors diverged 2.3 million years ago. While the G genome of Timopheevi was derived from Aegilops speltoides, the B genome of durum and common wheat was from an unknown source. Objective 2 Genomics-Facilitated Germplasm Enhancement We developed EMS-mutagenesis population for SD spring wheat cultivar Brick, NE winter wheat cultivar Overland (cultivated most in west SD) and SD soybean cultivar Surge. For the wheat mutagenesis populations, DNA has been isolated from the M2 individuals and the seeds are catalogued. In these M2 populations, albino and lesion mimic mutants were observed suggesting mutagenesis was effective. From the soybean mutagenesis population (M2), we recovered several interesting mutants, such as pentafolium, glabra, brown trichome, cupping leaf, small-pod etc. Objective 3. Genomics of Abiotic Stress Iw2 was mapped to tip of chromosome 2DS. Mapping of Iw1, Iw3, W1 and W2 is under way. Water loss and chlorophyll bleaching tests showed that Iw genes significantly increased cuticle permeability, indicative of a role of wheat cuticle in protecting non-stomatal transpiration. We are profiling 30 genes coding for cuticle biosynthetic enzymes, lipid transporters and transcription factors in cuticle pathway by qRT-PCR. We also got progress in wheat root studies. Interaction of two dominant genes, Vsr1 and Vsr2 triggers defense response pathway and caused very short root phenotype due to loss of root apical meristem. The Vsr1 and Vsr2 were mapped to the long arm of chromosome 5D. Objective 4. Feedstock Genomics Funded by DOE through NC SUN GRANT, we are developing solid-stem Triticale as a feedstock for biofuel production. We obtain hybrids for 74 combinations. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Isolation of Br2 gene, a major determinate of wheat domestication will allow us to understand the selection process during domestication and the signaling pathways of wheat spike development. Mutants are invaluable resources for biological studies. Mutants found in this program will be used for wheat and soybean biology of the agronomic traits. Cuticular wax is critical in preventing water loss via non-stomatal evaporation. Mapping and cloning of the wax and wax-inhibitor genes will eventually lead to dissection of the wax pathways and allow us to regulate the cuticular wax to enhance wheat tolerance to drought. Also these genes will tell us their history during the domestication and modern breeding process. Triticale is used as a cover crop in Corn-Belt. Recent study showed it can be used for feedstock production without competition of land with food crops. But current cultivars were bred for grain. Development of solid-stem Triticale will hopefully lay a found for biomass-orientated breeding of this man-made crop. No molecular study on wheat root is available. The very short root phenotype presents a very unique phenomenon of genetics and physiology of plant root development. This may provide us a window for new insights of root development.

Publications

  • Zhu H, Wang W, Zhang Z, Challa GS, Li W. 2011. Dominant gene interaction causes very short root phenotype in wheat. Plant and Animal Genome Conference XX (http://pag.confex.com/pag/xx/webprogram/Paper3114.html).
  • Li W, Zhu H, Wang J, Challa GS, Gill BS. 2011. A cytoplasmic view of polyploidy evolution. Plant and Animal Genome Conference XX (accepted, http://pag.confex.com/pag/xx/webprogram/Paper3113.html).


Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: Objective 1. Molecular Genetics of Wheat Domestication. Br2 is a major determinate of wheat domestication. We mapped this gene previously to the long arm of chromosome 3D of Aegilops tauschii, the D-genome donor species of common wheat. In 2010, we developed 9 new markers tightly flanking Br2 based on wheat-rice colinearity. Genotyping a population of 3,000 F2 individuals with the flanking markers identified 120 recombinants. The closest marker was used for screening Ae. tauschii BAC libraries and identified a contig of 52 BAC clones. Objective 2 Genomics-Facilitated Germplasm Enhancement. We developed EMS-mutagenesis population for SD spring wheat cultivar Brick, NE winter wheat cultivar Overland (cultivated most in west SD) and SD soybean cultivar Surge. For the wheat mutagenesis populations, DNA has been isolated from the M2 individuals and the seeds are catalogued. In these M2 populations, albino and lesion mimic mutants were observed suggesting mutagenesis was effective. From the soybean mutagenesis population (M1), we identified numerous mutants, such as lesion mimic, dwarf, cupping leaves, crinkle leaves, brown trichomes, small pods, etc. Objective 3. Characterization of Epidermome Crosses were made using near isogenic lines for cuticular wax production genes W1 and W2 and for wax inhibition genes Iw1 and Iw2. Five markers have been developed for Iw2. Mapping of Iw2 is under way. We also identified two wax mutants. The first wax mutant was found in SD spring wheat Brick and the mutant has much less wax compared to the wild type. The second mutant was found in a transgenic progeny and completely lost wax. Genetic analysis indicated a wax production gene was mutated. Objective 4. Feedstock Genomics. We just get a project funded by DOE through NC SUN GRANT to develop solid-stem Triticale as a feedstock for biofuel production. In addition to above proposed objectives, we also made important discovery in wheat root study. We found interaction of two genes caused a very short root phenotype in early seedling. With support from SDSU, we analyzed the gene expression underlying the very short roots vs. the normal root and found that 237 genes up-regulated and 12 down-regulated. A significant portion of the up-regulated genes are functioning in defense response pathway. PARTICIPANTS: Wanlong Li, Junwei Wang, Zhengzhi Zhang TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Isolation of Br2 gene, a major determinate of wheat domestication will allow us to understand the selection process during domestication and the signaling pathways of wheat spike development. Mutants are invaluable resources for biological studies. Mutants found in this program will be used for wheat and soybean biology of the agronomic traits. Cuticular wax is critical in preventing water loss via astomatal evaporation. Mapping and cloning of the wax and wax-inhibitor genes will eventually lead to dissection of the wax pathways and allow us to regulate the cuticular wax to enhance wheat tolerance to drought. Also these genes will tell us their history during the domestication and modern breeding process. Triticale is used as a cover crop in Corn-Belt. Recent study showed it can be used for feedstock production without competition of land with food crops. But current cultivars were bred for grain. Development of solid-stem Triticale will hopefully lay a found for biomass-orientated breeding of this man-made crop. No molecular study on wheat root is available. The very short root phenotype presents a very unique phenomenon of genetics and physiology of plant root development. This may provide us a window for new insights of root development.

Publications

  • No publications reported this period