AUTHOR=Cheng Peng , Wang Zihao , Ren Yanyan , Jin Pengfei , Ma Kangjie , Li Qiang , Wang Baotong 

TITLE=Silencing of a Wheat Ortholog of Glucan Synthase-Like Gene Reduced Resistance to Blumeria graminis f. sp. tritici

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.800077

DOI=10.3389/fpls.2021.800077

ISSN=1664-462X

ABSTRACT=<p>Wheat powdery mildew, caused by the obligate biotrophic ascomycete fungal pathogen <italic>Blumeria graminis</italic> f. sp. <italic>tritici</italic> (<italic>Bgt</italic>), is a major threat to wheat production worldwide. It is known that <italic>Arabidopsis thaliana glucan synthase-like 5</italic> (<italic>AtGSL5</italic>) improves the resistance of wheat to powdery mildew by increasing its anti-penetration abilities. However, the function of glucan synthase-like (<italic>GSL</italic>) orthologs in crop species remains largely unknown. In this study, <italic>TaGSL22</italic>, a novel functional ortholog of <italic>AtGSL5</italic>, was isolated as the only <italic>Bgt</italic>-induced <italic>GSL</italic> gene in wheat. Phylogenetic analysis indicated that <italic>TaGSL22</italic> was conserved within the group of Gramineae and showed a closer relationship to <italic>GSL</italic> orthologs from monocots than to those from dicots. The <italic>TaGSL22</italic> transcript was highest in the wheat leaves, followed by stems then roots. <italic>TaGSL22</italic> was localized in the cell membrane and cytoplasm of wheat protoplasts, as predicted by transmembrane structure analysis. In addition, expression of <italic>TaGSL22</italic> was induced by the plant hormones ethylene (ETH) and salicylic acid (SA), but down-regulated by jasmonate (JA) and abscisic acid (ABA). The transcript level of <italic>TaGSL22</italic> was up-regulated in the incompatible interaction between <italic>Bgt</italic> and wheat, whereas it remained relatively unchanged in the compatible interaction. Knocking down of <italic>TaGSL22</italic> by virus-induced gene silencing (VIGS) induced a higher infection type in the wheat–<italic>Bgt</italic> interaction. The <italic>TaGSL22</italic>-silenced plants exhibited reduced resistance to <italic>Bgt</italic>, accompanied by decreased callose accumulation. Our study shows a conserved function of <italic>GSL</italic> genes in plant immunity associated with penetration resistance, and it indicates that <italic>TaGSL22</italic> can be used to improve papilla composition and enhance resistance to wheat powdery mildew.</p>