Silencing of a Wheat Ortholog of Glucan Synthase-Like Gene Reduced Resistance to f. sp. .

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