First Report of Corynespora cassiicola Causing Fruit Rot of Pomegranate in India, Its Morphological and Molecular Characterization

Abstract

A new fungal pathogen, Corynespora cassiicola was isolated from infected pomegranates from orchards of Maharashtra. It causes a mild form of rot in pomegranates. The pathogen was isolated from only 5.12% of infected pomegranates of Bhagwa and Ganesh varieties. It produced approximately 12 mm rot on artificially infected pomegranates and necrosis was 8 mm deep after 10 days post inoculation. The pathogen was identified by cultural and morphological characteristics that include growth on different media and slide culture technique. Further authentication was done by the sequencing of ITS1, 5.8S and ITS2 region of rRNA gene. The accession number of sequence submitted to NCBI is KC411916. The pathogen produced plant cell wall degrading enzymes viz., pectinase, cellulase and xylanase. In artificially infected tissues, pectinase activity was maximum (19.8 U/g) followed by xylanase (15.58 U/g) and cellulase (1.09 U/g). Pearson correlation indicated a significant correlation (P < 0.05) between disease rating scale and enzyme activity in infected tissues. The elevated levels of pectinase, cellulase and xylanase suggest their possible role in pathogenesis and tissue degradation. Enzyme inhibitors from biocontrol agents may be further studied to prevent the progress of infection. This is the first description of characterization of C. cassiicola as a pomegranate fruit rot pathogen.