Characterization of a cross genera fungus, Exserohilum rostratum causes leaf spot disease of Tinospora cordifolia (Willd.) Miers Meena Ram Prasnna*, Kadam Vasudha A., Minipara Dipal, Kalariya Kuldeepsingh A., Saran Parmeshwar Lal ICAR-Directorate of Medicinal and Aromatic Plants Research, Anand-387310, Gujarat, India *Corresponding author e-mail: rp.meena@icar.gov.in
Online published on 20 June, 2022. Abstract During rainy season of 2017–18, leaf spot symptoms were observed on giloy at ICAR-DMAPR, Anand. At the initial stage small brown spots were developed which gradually turned into dark brown to black with the ash coloured centre. The retrieved pure culture of fungus was further used to establish the Koch's postulates and pathogenicity on the other hosts. The circular colonies of grey to deep brown colour with abundant cottony aerial mycelium were grown on PDA. The fungus produced geniculate, cylindrical, septate dark brown conidiophores, which were varying 4 to 6 μm in thickness with an inflated or swollen basal cell. The conidia were deep olivaceous brown coloured of 14 x 72 μm size with 8–9 septation and produced a typical protruding truncate hilum at the basal cell. Further, the sequence of internal transcribed spacer (ITS) region of the pathogenic fungus (AET-1 isolate, MK911727.1) using ITS1/ITS4 primers, and sequence identity confirmed the fungus as Exserohilum rostratum. The experiment on host range demonstrated that AET-1 isolate from giloy, also able to infect and develop typical symptoms on the cross genera species viz., Costus speciosus and Vigna mungo. Top Keywords Giloy, Pathogenicity, Morphology, Conidia, Geniculate, Internal transcribed spacer, Cross genera. Top |