Unravelling the proteome of Saccharum officinarum cv. BO91 for novel defense-related proteins during C. falcatum infection

Red rot, caused by Colletotrichum falcatum, is one of the most destructive diseases of sugarcane that affects the production sugarcane to a huge extent in India. In the present study, moderately red-rot resistant Saccharum officinarum cv. BO91 was inoculated with virulent C. falcatum (CF8) at grand growth phase. Stalk samples were taken at different time intervals to analyze the differentially abundant proteins through nanoLCMS/MS-based proteome analysis. The results indicated that the total number of identified peptides were significantly high (4026) in healthy sugarcane stalks, compared to fungal infected stalks. C. falcatum infection caused a drastic reduction in the number of peptides in sugarcane stalks at different time intervals (2565 at 3 h, 2610 at 6 h, and 2111 at 24 h). However, we found 97 exclusively abundant proteins in fungal infected stalks of sugarcane. Plenty of these proteins have already been functionally characterized in different other crop plants for their association with defense responses. The defense-related proteins included 30S ribosomal protein S15, bifunctional purine biosynthesis protein, CaM-binding domain-containing protein, kaurene synthase-3, DUF family protein, Ig-like domain repeat protein, methyl-accepting chemotaxis protein, O-fucosyltransferase family protein, coproporphyrinogen III oxidase, phenylalanine ammonia-lyase, phosphoglycerate kinase, receptor-like serine/threonine-protein kinase, scarecrow/scarecrow-like protein, and porphobilinogen deaminase. Though majority of commercially grown sugarcane cultivars are susceptible to the red rot pathogen, the proteome of BO91 cultivar displayed the differential abundance of a number of proteins involved in the stimulation of defense responses.