Isolation, identification, carbon utilization profile and control of Pythium graminicola, the causal agent of chilli damping‐off

Abstract

AbstractPostemergence damping‐off of chilli caused by Pythium spp. is a common and serious problem in large chilli growing areas of India under the moist conditions that generally prevails during the sowing period. Therefore, in order to better understand this disease, an isolate belonging to the genus Pythium (Pythiales) was isolated from the infected chilli (Capsicum annuum L.) plant root parts collected from the fields of Chandauli district, Uttar Pradesh, India. Based on the congruence of cultural, morphological, cardinal growth rate and the sequence data analysis, the isolate was identified as Pythium graminicola. The molecular phylogenetic analysis based on ITS‐rDNA sequences clustered the isolate with representative sequences for P. graminicola from GenBank in the Pythium clade. The isolate carbon utilization profiles were characterized using Biolog FF MicroPlate method. The results revealed that the isolate used a wide range of carbon sources, mainly carbohydrates, but also amino acids, suggesting the use of metabolic routes that include glycolysis/gluconeogenesis. Moreover, an in vitro colony growth inhibition assay was performed to determine the influence of chemical (fungicides) and biological (bacteria and fungi) antagonists over the pathogen using the poison plate and dual culture method, respectively. Overall, the results revealed that the presence of aggressive broad range biocontrol agents can be used as an effective environmentally friendly approach for management and control of damping‐off in production systems. The antagonist can serve as a bio‐efficient and eco‐friendly alternative to synthetic fungicides for the development of an effective integrated pest management (IPM) system and obtaining higher yields.