Progress 10/01/08 to 09/30/14
Outputs
Target Audience: Graduate students working on genetics, breeding, and molecular breedings Wheat or temperate cereal crop breeders Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? A Ph.D. student (Dr. Shuwen Wang, The Land Institute) and a M.S. student (Ms. Lei Lei) were trained in molecular genetics, gene mapping, and marker development. A visiting scientist was trained in molecular breeding. How have the results been disseminated to communities of interest? Presented in professional meetings Lei, L., X. Zhu, S. Wang, BF. Carver, L. Yan, Allelic variation in TaMFT-3A is associated with seed dormancy/ germination in winter wheat, Plant and Animal Genomics Conference, San Diego, CA. January 11-15, 2013. Wang, S., L. Yan, B. Carver. 2008. Genetic basis of heat sensitivity germination in wheat. National Wheat Genomics, Indianapolis, IN, December 4-6, 2008. Published scientific journals Lei, L., X. Zhu, S, Wang, M. Zhu, B.F. Carver, L. Yan, 2013. TaMFT-A1 is associated with seed germination sensitive to temperature in winter wheat. PLoS One 8(9): e73330. doi:10.1371/journal.pone.0073330. Lei L. 2012 TaMFT-A1 is associated with seed germination sensitive to temperature in winter wheat. M.S. Thesis, Oklahoma State University. Wang S. 2010 Quantitative trait loci contributing to high temperature seed dormancy in winter wheat. Ph.D. Thesis, Oklahoma State University. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Seed germination is an important trait in winter wheat that occupies approximately 75% of the wheat worldwide. The ability of seed to germinate under favorable environmental regimes is critical for seedling emergence, plant establishment, subsequent development and growth of adult plants. Seed germination is controlled by given internal factors and external conditions such as temperature. Winter wheat in the southern Great Plains is often planted six weeks before the optimal planting date to produce more biomass to graze the cattle during the winter season. High germinability in the high soil temperature is required to adapt this specific management system. However, some cultivars can germinate at the optimum temperature but cannot germinate at a high temperature, and little is known about the genetic basis and molecular mechanism underlying temperature sensitivity germination in winter wheat. We mapped a major QTL for temperature-sensitive germination on the short arm of chromosome 3A (QTsg.osu-3A) in the RIL population generated from two winter wheat cultivars. Furthermore, we found that TaMFT-A1, which was reported to regulate seed dormancy in spring wheat cultivars, was tightly associated with the peak of QTsg.osu-3A. TaMFT-A1 was mapped associated with the seed dormancy and pre-harvest sprouting, based on a single nucleotide polymorphism in the promoter region (Nakamura et al. 2011) or a 1-bp deletion in coding region (Liu et al., 2013). However, we found that the Jagger TaMFT-A1 allele a novel haplotype that may invoke different mechanisms for controlling seed dormancy/germination among diverse wheat cultivars. Main Research Activities and Objectives We have conducted and completedfollowing research activities based on the objectives of this project. A mapping population was generated using two locally adapted winter wheat cultivars, Jagger and 2174. The population was genotyped using SSR markers and gene markers to locate genomic regions that affect seed dormancy The population was phenotyped under low temperature, normal temperature, and high temperature conditions to characterize segregation in seed dormancy. TaMFT-A1 was completely sequenced to find variation between the Jagger allele and the 2174 allele, and a PCR marker for TaMFT-A1 was developed. TaMFT-A1 was characterized for transcriptional levels under different temperatures and storage times. TaMFT1 marker was used to genotypes tetraploid wheat and contemporary winter wheat cultivars. Main Results We have obtained main results listed below: The mean germination rate at the optimal temperature (constant 25ºC) was between 30% for 2174 and 60% for Jagger when their seeds were harvested one week, but reached approximately 90-95% at 6 weeks after harvest for both of the tested cultivars. The 96 recombinant inbred lines of Jagger x 2174 showed segregation in germination rate at different temperature regimes. Approximately 400 SSR markers were mapped in the population. A QTL for seed germination at high temperature and normal temperature was consistently mapped on the distal end of the short arm of chromosome 3A, and the QTL for temperature sensitivity germination is thus referred to QTsg.osu-3A. QTsg.osu-3A had LOD scores ranging from 2.6 to 6.2 accounted for 11.8-26.2% of the total phenotypic variation in seed germination tested at different years and different temperatures. The whole gene of TaMFT-A1 consisting of 4 exons and 3 introns from each of the Jagger and 2174 alleles was finally obtained via a pair for primers specific to chromosome 3A. The sequenced TaMFT-A1 gene was 4,423 bp for the Jagger allele and 4,330 for the 2174 allele, which included 1000 bp upstream from the start codon for the Jagger allele, 1012 bp upstream from the start codon for the 2174 allele, as well as 401 bp downstream from the stop codon for each of the Jagger and 2174 alleles. Overall, there was 96% identity between the Jagger allele and 2174 allele showing 87 SNPs and 12 indels (insertions/deletions) with sequences from 1 to 20 bp. Two SNPs occurred in exons, one that occurred in exon 1 but did not cause alternation of amino acid, and the other that occurred in exon 2 resulting in an alternation of an amino acid between Arginine residue in Jagger to Lysine residue in 2174. A PCR marker was developed to map TaMFT-A1 in the Jagger x 2174 RILs. The TaMFT-A1 transcript level of Jagger was significant higher than that of 2174 at 2 weeks after harvesting. The TaMFT-A1b transcript level was significantly decreased after harvesting. Among 34 winter wheat varieties released in the southern Great Pains in recent years, one half of them were found to carry the Jagger TaMFT-A1a allele and the other half were found to carry the 2174 TaMFT-A1b allele. Among 18 pairs of parental lines that were used to construct mapping populations in the WheatCAP applied genomics project, 24 parental lines were found to carry the Jagger TaMFT-A1a allele and the remaining 14 parental lines were found to carry the 2174 TaMFT-A1b allele. Among 56 Chinese spring wheat cultivars/landrace, 20 were found to carry the Jagger TaMFT-A1a allele and the remaining 36 were found to carry the 2174 TaMFT-A1b allele. Among 9 tetraploid wheat accessions of T. turgidum tested, only 1 accession showed the same allele as Jagger and the other 8 accessions showed the same allele as 2174, suggesting the two alleles have been diversified at the tetraploid level. All of 3 diploid wheat accessions of T. urartu tested showed the same allele as Jagger, suggesting that the Jagger TaMFT-A1a allele is an ancestral type. Discussion The initial goal of this study aimed to identify genetic loci associated with the sensitivity of seed germination to temperature in winter wheat. After a major QTL for temperature-sensitive germination was mapped, this study focused on allelic variation in TaMFT-A1 in winter wheat. Allelic variation in TaMFT-A1 was also associated with seed germination in the winter what population of recombinant inbred lines generated from two winter wheat cultivars in U.S. southern Great Plains. The results from this study can be directly utilized in breeding of winter wheat in the southern Great Plains. This study not only validated the function of TaMFT-A1 in winter wheat but also developed a new PCR marker with greater efficiency and less cost to track the presence, or absence, of the Jagger TaMFT-A1 haplotype in wheat, facilitating molecular breeding. Broad Impacts The initial goal of this study aimed to test if any of flowering time genes VRN1 (=AP1) and VRN3 (=FT) is associated with the sensitivity of seed germination to temperature in winter wheat. After a major QTL for temperature-sensitive germination was mapped associated with TaMFT-A1, this study concluded that of seed germination was not associated with VRN1 or VRN3 but with Mother of FT genes. The Jagger TaMFT-A1 is a novel haplotype, and it exists in extensive spring and winter cultivars collected from different geographical areas. Spring wheat seed usually has no or weak dormancy that results in immediate germination even pre-harvest sprouting, whereas winter wheat usually has strong dormancy that prevents germination even for the seed that has been stored for several months. Winter wheat and spring wheat may not share common biological mechanisms controlling seed germination, because their seeds are produced under different environment regimes. The outcome from this study has provided an opportunity to compromise the efforts of TaMFT-A1 on seed dormancy, pre-harvest sprouting, and high temperature germination sensitivity in wheat breeding. New efforts should be made to find cultivars which germination is insensitive to high temperature, and such cultivars will be suitable for early sowing in the dual-purpose wheat production.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2013
Citation:
Lei Lei, 2013 TaMFT-A1 is associated with seed germination sensitive to temperature in winter wheat. M.S. Theses, Oklahoma State University
|
Progress 10/01/12 to 09/30/13
Outputs
Target Audience: Environmental and Genetic Determinants of Seed Quality and Performance In the previous study, we found that high temperature germination sensitivity was genetically controlled by a major QTL (Qhtgs.osu-3A) on the short arm of chromosome 3A in the winter wheat populations of recombinant inbred lines (RILs) generated from the locally adapted cultivars, Jagger x 2174. We have found that the gene TaMFT-3A, mother of FT (FLOWERING LOCUS T) and TFT1 (TERMINAL FLOWER1) genes on chromosome 3A that was reported to control seed germination in spring wheat, was located on the peak of Qhtgs.osu-3A in winter wheat, however, allelic variation in TaMFT-3A between the two winter wheat cultivars differed from that observed in spring wheat cultivars. These findings suggest that TaMFT-3A may invoke different mechanisms for controlling seed dormancy/germination among diverse wheat cultivars. The Jagger TaMFT-A1 is a novel haplotype, and it exists in extensive cultivars collected from different geographical areas. We have also developed a new PCR marker with greater efficiency and less cost to track the presence, or absence, of the Jagger TaMFT-A1 haplotype in wheat. The Jagger TaMFT-A1 allele in this winter wheat can be introduced to spring wheat cultivars as to avoid pre-harvest sprouting. This original research article has been published in PLoS One. 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?
Identified allelic variation in TaMFT-A1 sequence and a molecular marker was developed for allelic variation
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Lei, L., X. Zhu, S, Wang, M. Zhu, B.F. Carver, L. Yan, 2013. TaMFT-A1 is associated with seed germination sensitive to temperature in winter wheat. PLoS One 8(9): e73330. doi:10.1371/journal.pone.0073330.
|
Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: In the previous study, we found that high temperature germination sensitivity was genetically controlled by a major QTL (Qhtgs.osu-3A) on the short arm of chromosome 3A in the winter wheat populations of recombinant inbred lines (RILs) generated from the locally adapted cultivars, Jagger x 2174. The effect of Qhtgs.osu-3A on seed germination was consistent when the seed was treated with room temperature, suggesting the effect of Qhtgs.osu-3A was controlled in innate genetic factors. We have found that the gene MFT, a gene that was reported to control seed germination in spring wheat, was located on the peak of Qhtgs.osu-3A. We are sequencing the MFT gene to find allelic variation for seed germination in winter wheat. PARTICIPANTS: Liuling Yan, PI, designed experiemnts, analyzed results, and wrote reports. Lei Lei, MS student, perfomed experiments and analyzed results. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Winter wheat in the southern Great Plains is preferred to plant as early as in the early of September to produce more wheat biomass as forage for cattle to graze during the following winter season. A high germinability of seed in the presence of high temperature is required to adapt to the specific agronomic management system. The marker developed from this study will be used to eliminate the allele that causes low germination at a high temperature.
Publications
- No publications reported this period
|
Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: We have experimentally demonstrated that the effect of Qhtgs.osu-3A on seed germination was regulated by temperature. We have mapped two gene markers on the distal end of the short arm of chromosome 3A. PARTICIPANTS: Genqiao Li: Senior Research Specialist, Plant and Soil Sciences, Oklahoma State University. Xinkai Zhu, Visiting professor, Yangzhou University, China. TARGET AUDIENCES: Researchers and farmers who wish to know appropriate planting time of winter wheat. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
In the previous study, we found that high temperature germination sensitivity was genetically controlled by a major QTL on the short arm of chromosome 3A (Qhtgs.osu-3A)in two winter wheat populations of recombinant inbred lines (RILs) generated from the locally adapted cultivars, Intrada x Cimarron and Jagger x 2174. In the present study, we tested the same set RILs of the Jagger x 2174 population for response in germination to low temperature, high temperature, and normal temperature. Results showed that Qhtgs.osu-3A disappeared when the seeds of the population were treated at 4 degrees C for 3-7 days or were kept at normal temperature at 25 degrees C. The results demonstrated that the effect of Qhtgs.osu-3A on seed germination was regulated by temperature. The further work is to fine map the gene sensitive to temperature. We have also developed markers for two genes, ABC-3A and HSP16, and mapped them on the distal end of the short arm of chromosome 3A. The two markers were not associated with Qhtgs.osu-3A, but helped us to determine the orientation of the physical location of Qhtgs.osu-3A in the future study.
Publications
- No publications reported this period
|
Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: Dormancy of wheat seeds may be broken by many stimuli, such as cold and heat. We have tested the effects of low temperature and high temperature on germination in the recombinant inbred lines (RILs) population generated from a cross between two winter wheat varieties: Jagger and 2174. Up to date, studies on dormancy and germination of wheat seeds have been focused with relevance to pre-harvest sprouting, and little is known about the genetic mechanisms underpinning seed germination at different temperatures before planting. PARTICIPANTS: Brett Carver: Professor in Breeding, Plant and Soil Sciences, Oklahoma State University. Shuwen Wang: Ph.D. student, Plant and Soil Sciences, Oklahoma State University. Xinkai Zhu, Visiting professor, Yangzhou University, China. TARGET AUDIENCES: Researchers and farmers who wish to know appropriate planting time of winter wheat. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We found that a major QTL on the short arm of chromosome 3A (Qhtgs.osu-3A) that was previously identified for high temperature germination sensitivity was also linked with variation in seed germination at normal temperature and that the variation disappeared when the same population was treated with low temperature, suggesting that the Qhtgs.osu-3A locus is regulated by temperature. The QTL QHtsd.osu-4A on chromosome 4A that was previously identified for high temperature germination sensitivity was detected at high temperature only, suggesting that the genes associated with the two QTLs have different mechanisms in controlling high temperature germination sensitivity in winter wheat.
Publications
- No publications reported this period
|
Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Winter wheat in the Southern Great Plains is preferred to plant in early September to increase forage production for the purpose of cattle grazing in a winter season. A negative consequence of early planting, however, is that seeds of many cultivars cannot germinate in the presence of high temperature, a phenomenon called high temperature seed dormancy (HTSD). HTSD is of economic impact on production of winter wheat in the southern Great Plains of the USA. Up to date, studies on dormancy and germination of wheat seeds have been focused with relevance to pre-harvest sprouting, and little is known about the genetic mechanisms underpinning seed germination at high temperature before planting. Each year germination test on contemporary cultivars needs to be performed from late August to provide real-time information for farmers to choose high-temperature insensitive wheat cultivars. Characterization of HTSD at molecular level is in demand to facilitate its breeding efforts. PARTICIPANTS: Brett Carver: Professor in Breeding, Plant and Soil Sciences, Oklahoma State University. Shuwen Wang: Ph.D. student, Plant and Soil Sciences, Oklahoma State University. Xinkai Zhu, Visiting professor, Yangzhou University, China. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We have tested two populations of recombinant inbred lines generated from two crosses, Intrada x Cimarron, Jagger x 2174, for their variation in seed germination under normal temperature and high temperature. As a result, two QTLs on the short arm of chromosome 3A (QHtsd.osu-3A) and chromosome 4A (QHtsd.osu-4A) had consistent and stable effects on seed germination across genetic backgrounds, years, and locations. SSR markers associated with these QTLs, Xbarc310 for (QHtsd.osu-3A) and Xgwm637 (QHtsd.osu-4A), can be used to assist selection in the wheat breeding programs.
Publications
- Wang, S., L. Yan, B.F. Carver (2009) Quantitative trait loci contributing to high temperature seed dormancy in winter wheat (in preparation).
|