AUTHOR=Cheng Xinran , Wang Shengxing , Xu Dongmei , Liu Xue , Li Xinyu , Xiao Weiwei , Cao Jiajia , Jiang Hao , Min Xiaoyu , Wang Jianfeng , Zhang Haiping , Chang Cheng , Lu Jie , Ma Chuanxi 

TITLE=Identification and Analysis of the GASR Gene Family in Common Wheat (Triticum aestivum L.) and Characterization of TaGASR34, a Gene Associated With Seed Dormancy and Germination

JOURNAL=Frontiers in Genetics

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2019.00980

DOI=10.3389/fgene.2019.00980

ISSN=1664-8021

ABSTRACT=<p>Seed dormancy and germination are important agronomic traits in wheat (<italic>Triticum aestivum</italic> L.) because they determine pre-harvest sprouting (PHS) resistance and thus affect grain production. These processes are regulated by <italic>Gibberellic Acid-Stimulated Regulator</italic> (<italic>GASR</italic>) genes. In this study, we identified 37 <italic>GASR</italic> genes in common wheat, which were designated <italic>TaGASR1-37</italic>. Moreover, we identified 40 pairs of paralogous genes, of which only one had a Ka/Ks value greater than 1, indicating that most <italic>TaGASR</italic> genes have undergone negative selection. Chromosomal location and duplication analysis revealed 25 pairs of segmentally duplicated genes and seven pairs of tandemly duplicated genes, suggesting that large-scale duplication events may have contributed to the expansion of <italic>TaGASR</italic> gene family. Microarray analysis of the expression of 18 <italic>TaGASR</italic> genes indicated that these genes play diverse roles in different biological processes. Using wheat varieties with contrasting seed dormancy phenotypes, we investigated the expression patterns of <italic>TaGASR</italic> genes and the corresponding seed germination index phenotypes in response to water imbibition, exogenous ABA and GA treatment, and low- and high-temperature treatment. Based on these data, we identified the <italic>TaGASR34</italic> gene as potentially associated with seed dormancy and germination. Further, we used a SNP mutation of the <italic>TaGASR34</italic> promoter (-16) to develop the CAPS marker GS34-7B, which was then used to validate the association of <italic>TaGASR34</italic> with seed dormancy and germination by evaluating two natural populations across environments. Notably, the frequency of the high-dormancy <italic>GS34-7Bb</italic> allele was significantly lower than that of the low-dormancy <italic>GS34-7Ba</italic> allele, implying that the favorable <italic>GS34-7Bb</italic> allele has not previously been used in wheat breeding. These results provide valuable information for further functional analysis of <italic>TaGASR</italic> genes and present a useful gene and marker combination for future improvement of PHS resistance in wheat.</p>