Defense responses against the sorghum anthracnose pathogen in leaf blade and midrib tissue of johnsongrass and sorghum

Abstract Three isolates of Colletotrichum sublineolum P. Henn were inoculated on leaf blades and midribs of twenty-six johnsongrass cultivars with two sorghum cultivars, BTx 623 and SC 748-5 by using an excised leaf method. Phenotypic host responses from no response to severe infection, were observed. Some johnsongrass cultivars and BTx 623 showed different responses between the two tissues. Expression of six defense response related genes were measured using Real-time qRT-PCR. Leaf blade and midrib showed different patterns in BTx 623 inoculated with C. sublineolum ; high expression of CHS8 and TLP were measured in midrib at 24 and 48 hpi respectively.