Resistance to anthracnose leaf blight in sorghum

Sorghum is one of the most important cereal crops in the world, and most of the production of grain sorghum occurs in the United States. But production of sorghum is limited by economically important diseases which lower the production of sorghum. Sorghum anthracnose may cause from 50 to 86% yield losses and is caused by a hemi-biotrophic fungal pathogen Colletotrichum sublineola. The pathogen is host specific and survives on seeds, mycelium, conidia, and soil. There are three forms of the disease: leaf blight, stalk rot, and panicle and grain rot. Anthracnose leaf blight is usually encountered 30-40 days after planting and is responsible for most of the yield loss. Common anthracnose leaf blight symptoms in sorghum include chlorotic flecks on leaves, necrotic blotches on the leaf lamina, and midrib necrosis. The symptoms often vary due to different reactions of sorghum lines and due to variants of the pathogen. Qualitative and quantitative host resistance has been reported for anthracnose leaf blight. However, the evolving nature of the pathogen increases the need to identify more resistance sources that are effective against isolates collected from different locations. In addition, little is known about the mechanisms of resistance to sorghum anthracnose. In this study, I conducted association mapping complemented by mutant screening and identified different resistance loci and candidate genes linked to host resistance. The most interesting candidate genes reported here are Sobic.005G063200, Sobic.007G023600 and Sobic.003G396000. I also identified the molecular pathways (2OG-FeII_Oxy Domain, EF-hand_7 Domain, Abhydrolase_6 Domain, DUF4228 Family, HMA Domain, LRR_7 repeat domain) responsible for resistance to anthracnose leaf blight. The findings from this study will be important in understanding the resistance mechanism and useful in disease resistance breeding for sorghum