Molecular Characterization of Pyricularia oryzae and its Management by Stem Extract of Tribulus terrestris

Abstract

Rice blast disease caused by Pyricluaria oryzae Cavar is one of the most destructive diseases of rice responsible for higher yield losses all around the world. In the present study, morphological and molecular characterization of P. oryzae and its management by stem extracts of Tribulus terrestris L. was carried out. In a laboratory bioassay, methanolic stem extract of 1, 2, 3, 4 and 5% concentrations significantly reduced biomass of P. oryzae by 35-43%. Methanolic extract was successively fractionated using four organic solvents. Bioassays with various concentrations (1.562, 3.125, 6.25……., 200 mg mL-1) of these fractions showed that chloroform and ethyl acetate fractions were highly antifungal resulting in 54-82% and 16-85% suppression in biomass of P. oryzae, respectively. Chloroform fraction was analyzed by GC-MS that revealed 17 compounds. 1, 3-benzenedicarboxylic acid, bis (2-ethylhexyl) ester (20.69%), octacosane (11.20%), heptacosane (9.67%), octadecane, 6-methyl-(5.40%), n-hexadecanoic acid (4.82%), pentadecanoic acid, 14 methyl-, methyl ester (3.80%) and apiol (3.71%) were the predominant compounds. In conclusion, stem of T. terrestris contains potent antifungal compounds which can be exploited for management of P. oryzae.