<i>MC69</i> is necessary for appressorial penetration and pathogenicity of a laboratory strain 70-15.

<p>(A) <i>MC69</i> is required for pathogenicity of <i>M. oryzae</i> strain 70-15. Conidial suspension of the wild-type strain 70-15 (70-15 WT) and the <i>mc69</i> mutants (<i>mc69-119</i>, <i>-31</i>) were inoculated on barley (cv. Nigrate) and rice (cv. Shin No. 2) leaves, and incubated for 7 days. (B) Germination, appressorium formation and appressorial penetration of 70-15 WT and the <i>mc69</i> mutants. The ratio of germination was calculated as the mean percentage of conidia germinated after 32 h on rice (cv. Shin No. 2) leaf sheath cells. The mean percentage of appressorium formation on rice leaf sheath cells among the germinated conidia is presented. Three replicates of ∼50 conidia were counted for each observation. The mean percentage of appressorial penetration by the <i>mc69</i> mutants is presented 32 h after inoculation. Standard errors are indicated by the vertical bars.