Identification of Turcicum leaf blight resistance genes in sorghum using comparative genomics

Turcicum leaf blight, caused by Exserohilum turcicum (Pass) K.J. Leonard and E.G. Suggs (teleomorph: Setosphaeria turcica (Luttrell) Leonard and Suggs), formerly known as Helminthosporium turcicum, is a major foliar disease of both sorghum and maize. In comparison with sorghum, a lot more studies have been done on maize to identify quantitative trait loci (QTL) and major genes playing a role in observed resistance and/ or tolerance to the pathogen. Comparative analysis was undertaken of the maize remorin gene ZmREM6.3, which has been identified to have a significant contribution towards turcicum leaf blight resistance. The gene ZMREM6.3 was retrieved from the maize database. This was used to search the sorghum database in Phytozome. The SNP markers were developed using the orthologous sorghum remorin gene. These markers were validated across diverse sorghum accessions and a recombinant inbred line (RIL) mapping population at F8:9. The previously obtained field phenotyping data were used to establish the association of various SNP markers with resistance/susceptibility to the fungus. Association of the markers to the trait was determined using both General Linear Model (GLM) and the Mixed Linear Model (MLM) in TASSEL software for association mapping of complex traits in diverse samples. The maize remorin gene ZmREM6.3 has been identified in sorghum genome. This is likeliy to make a significant contribution towards breeding for turcicum leaf blight resistance.