Study the etiology of pomegranate wilt complex and their molecular characterization

Abstract

The stem and root regions of pomegranate wilted plants were collected from the field of northern Karnataka during 2017. The wilt causing pathogens Ceratocystis fimbriata and Fusarium oxysporum were isolated from from stem and roots of infected plant parts using carrot bait technique and standard tissue isolation technique respectively. Initially C. fimbriata produced hyline endoconidia after 5 days of tissue inoculation with size of12 to 21 μm long x 8 to 18 μm wide and followed by formation of perithecia after 9 days of incubation with a globose base, which was in the size of 145 to 290 μm. Endoconidia were hyline with size of 12 to 21 μm long x 8 to 18 μm wide.Olive brown aleurioconidia were present either singly or in chains with globose to oval shape with 11 to 22 μm diameter. In presence of water it exuded small, hyaline, hat shaped ascospores one after another from its long. Mycelium of Fusarium oxysporum was white to creamish yellow in colour.Hyphae are septate, hyline and produced both macro and microconidia. Numerous chlamydospores were observed as the culture gets old and they occur both singly and in chains. Isolation of genomic DNA and PCR confirmation was done by agarose gel electrophoresis. ITS sequences of pathogens were confirmed as C. fimbriata and Fusarium oxysporum using bioinformatics tool NCBI (National Centre for Biotechnology Information) BLASTn programme and were deposited under accession number MN596926 (C. fimbriata) and MN596927(Fusarium oxysporum).