MoSrp1 is essential for full virulence.

(A) Representative disease lesions on leaves of susceptible barley cultivar (left panel) and rice cultivar (right panel) sprayed with conidia of P131, srp1ko1, and cSRP1. (B) Statistics on disease lesions formed by P131, srp1ko1, and cSRP1 on susceptible rice cultivar ‘LTH’. Lesions with gray centers and larger than 2-mm in diameter were counted as expanded lesions. Means and standard deviations were calculated from the lesions formed on the middle 5-cm of the fourth leaves. Three independent experiments were conducted with at least 10 leaves in each replicate. (C) The top leaves of rice seedlings at the four-leaf stage were abraded and inoculated with mycelium plugs of P131, srp1ko1, and cSRP1. Representative disease symptoms were photographed at 5 dpi. (D) Statistics on length of individual disease lesions formed by P131, srp1ko1, and cSRP1 on abraded rice leaves as described in (C). Means and standard deviations were calculated from three independent experiments, in each of which at least 10 leaves were inoculated for each of the strains. (E) Appressorial penetration and invasive hyphal growth of P131, srp1ko1, and cSRP1 in barley epidermis at 24 and 36 hpi. Asterisk marks appressorium. Bar, 10 μm. (F) Statistics on percentages of appressoria with distinct types of invasive hyphae (IH), primary IH, IH with 1–2 branches, and IH with more than 2 branches at 24 and 36 hpi. Means and standard deviations were calculated from three independent experiments each with at least 50 appressoria scored.