Molecular understanding of red rot resistance in sugarcane through genomics and proteomics

Abstract

Red rot of sugarcane caused by Colletotrichum falcatum Went is one of the devastating diseases of sugarcane causing significant loss to sugarcane production in the country. Complex polyploidy and lack of information on inheritance to red rot in sugarcane make breeding for red rot resistance more difficult. Studies were initiated at this institute on identifying red rot resistance mechanism in sugarcane. Studies conducted during the previous decades indicated possible role of oxidative enzymes, pathogenesis related (PR) proteins and 3-deoxyanthocyanidin phytoalexins in governing red rot resistance. Recent studies involving semi quantitative RT-PCR post pathogen challenge from sugarcane cultivars varying in red rot resistance, revealed differential accumulation of transcripts of the flavanoid biosynthetic pathway like coumarate-4-hydroxylase, chalcone synthase, chalcone transferase and this transcript analysis, further confirmed the role of sugarcane phytoalexins in red rot resistance. Similarly, the role of PR- proteins like chitinase and β-1,3-glucanase was established at the transcript level. Detailed molecular analysis applying differential display (DD)-RT-PCR identified expression of more number of differentially expressed transcripts during the host pathogen interaction. Full length sequences of many potential transcripts were identified and are being functionally annotated. Also to identify specific proteins involved in red rot resistance, proteomics approach has been attempted by optimizing sample preparation from stalk tissues, 2-D electrophoresis (2-DE), down stream processing of identified spots and bioinformatics. Several resistance-associated proteins spots were identified and they are being analyzed critically for their functional relevance