FIG. 9.

Effect of MVE1 gene deletion on pathogenicity of Mycosphaerella graminicola to wheat. (A) Spray infection assays. Identical quantities of inoculum (10⁸ spores) of the wild type (WT), an ectopic control strain (Ect), and four independent MVE1 gene deletion mutants (Δmve1-1, Δmve1-2, Δmve1-3, and Δmve1-4) were sprayed onto seedling leaves of the highly susceptible wheat cultivar Taichung 29. After inoculation, plants were placed in the dark for 48 h under high humidity. Subsequently, the infected wheat plants were incubated in a greenhouse with a diurnal cycle of 14 h of light/10 h of darkness for 21 days. The inoculation assays were performed with at least three biological replications for each fungal isolate. (B) Effects of the disruption of MVE1 on pycnidial pigmentation. The leaves of wheat cultivar Taichung 29 infected by the wild-type strain or the MVE1 gene deletion mutant (Δmve1) in panel A were harvested and analyzed under a dissecting microscope. The same stages of infected wheat leaves were selected and compared for the development of pycnidia between the wild type and Δmve1 mutant. Upper leaves indicate new development of STB still in progress, whereas the lower leaves were relatively old, with STB showing full development of pycnidia.