AUTHOR=Zhu Zhi , Wang Jingyi , Li Chaonan , Li Long , Mao Xinguo , Hu Ge , Wang Jinping , Chang Jianzhong , Jing Ruilian 

TITLE=A transcription factor TaMYB5 modulates leaf rolling in wheat

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.897623

DOI=10.3389/fpls.2022.897623

ISSN=1664-462X

ABSTRACT=<p>Leaf rolling is an important agronomic trait in wheat (<italic>Triticum aestivum</italic> L.). Moderate leaf rolling keeps leaves upright and maintains the relatively normal photosynthesis of plants under drought stress. However, the molecular mechanism of wheat leaf rolling remains unclear. Here, we identified a candidate gene <italic>TaMYB5-3A</italic> that regulates leaf rolling by using a genome-wide association study (GWAS) in a panel of 323 wheat accessions. Phenotype analysis indicated that the leaves of <italic>tamyb5</italic> mutants were flatter than that of the wild type under drought condition. A nucleotide variation in the <italic>TaMYB5-3A</italic> coding region resulted in a substitution of Thr to Lys, which corresponds to two alleles <italic>SNP</italic>-3A-1 and <italic>SNP</italic>-3A-2. The leaf rolling index (LRI) of the <italic>SNP</italic>-3A-1 genotype was significantly lower than that of the <italic>SNP</italic>-3A-2 genotype. In addition, <italic>TaMYB5-3A</italic> alleles were associated with canopy temperature (CT) in multiple environments. The CT of the <italic>SNP</italic>-3A-1 genotype was lower than that of the <italic>SNP</italic>-3A-2 genotype. Gene expression analysis showed that <italic>TaMYB5-3A</italic> was mainly expressed in leaves and down-regulated by PEG and ABA treatment. TaMYB5 induces <italic>TaNRL1</italic> gene expression through the direct binding to the AC <italic>cis</italic>-acting element of the promoter of the target gene, which was validated by EMSA (electrophoretic mobility shift assay). Our results revealed a crucial molecular mechanism in wheat leaf rolling and provided the theoretical basis and a gene resource for crop breeding.</p>