Identification of candidate secretory effector proteins (CSEPS) genes from Colletotrichum falcatum and their role in host-pathogen interaction by comparative modelling

Abstract

Protein-protein interaction during host-pathogen interface plays a vital role in initiating infection and is considered to be critical in understanding mechanisms of infection and defense response. Colletotrichum falcatum, an ascomycete fungal pathogen, infects sugarcane stalks and causes red rot. To decipher its molecular signature and pathogenicity, the genome and transcriptome of C. falcatum were sequenced using Illumina Hi-Seq 2000. The C. falcatum genome (48.2 Mb) was assembled de novo using the software SSpace & Velvet and the transcriptome (31 Mb) was assembled using Soap de novo. The genome of C. falcatum consisted of 12,270 genes, while its transcriptome revealed 13,320 genes, similar to the closely related species C. graminicola and C. sublineola that cause anthracnose in maize and sorghum, respectively. About 884 classical secretory proteins and 56 transmembrane helices were predicted from the C. falcatum transcriptome using SignalP. The C. falcatum secretory proteins have large number of CAZy families, esterase, peptidases, proteases, cytochrome P450, transporters, proteinase and transcription factors. An in silico prediction of proteins involved in host-pathogen interaction has been carried out using Cytoscape, which determined the pathways involved in establishing pathogen colonization and signal transduction, String Tool was used to predict functional protein involved in host pathogen interaction. The comparative modeling of protein-protein recognition from host-pathogen interaction and CSEPs predictions from genomic and transcriptomic context brought new understanding of the functions of effector proteins in host defense and fungal pathogenicity during the interaction