Identification and characterization of pectin lyase gene as a virulence factor in Colletotrichum gloeosporioides

C. gloeosporioides, a filamentous phytopathogenic fungus, secrets several enzymes during infection and degrades cell wall of the host plant causing anthracnose disease in plants worldwide. In the present study, leaves from four different infected plants (Litchi chinensis, Aegle marmelos, Mangifera indica and Syzygium jambolanum) were collected and four different fungi strains were isolated. They were confirmed as Colletotrichum gloeosporioides by 28s rDNA gene sequencing. The strains were screened for pectin lyase secretion by observing a zone of pectin utilization on pectin-agar plate assay using Congo red staining. The pectin lyase (pnl-1) gene from each strain was amplified using a specific primer and sequenced. The obtained sequences were analyzed for multiple sequence alignment, phylogenetic tree, sequence similarity matrix, pair-wise identity (using a heatmap), amino acid composition, conservation of amino acid residues and physicochemical properties. I-TASSER was used to elucidate its three-dimensional structure. Remarkable amino acid diversity was observed in pnl-1 gene in all the fungi studied. From the results of the physicochemical property of the protein it is observed that fungal pectin lyase have different pI values and amino acid compositions. The probable role of this pnl-1 gene in mechanisms of pathogenicity with the different hosts is discussed.