Zoospore encystment‑based and cabin sequestering methods for isolation and salvaging Phytophthora from infested rhizospheric soils

Abstract

Phytophthora, one among the most devastating phytopathogenic genus representing the oomycetes inflicts substantial damage to a broad spectrum of economically important horticultural crops worldwide. The rapid dissemination of Phytophthora in agro-ecosystems is mediated through bi-flagellated zoospores and their homing response towards the host is profoundly influenced by chemo-electrotactic mechanisms leading to encystment and subsequent colonization. Though different procedures are reported to isolate Phytophthora from infested rhizospheric soils, studies addressing zoospore encystmentbased method using different baits for isolation and subsequent retrieval of cultures (in case of bacterial contamination) are meagre in Phytophthorablack pepper host-pathosystem. In the present study, Phytophthora was isolated from infested rhizospheric soils of black pepper using different baits viz., thermocol, impregnated paper discs, leaves of Albizzia falcataria and green gram roots. Modified cabinsequestering methods were subsequently adopted to salvage the cultures in case of bacterial contamination, if any. The zoospore encystment-based method is cost effective and consumes lesser time for isolation of Phytophthora from infested rhizospheric soils of black pepper. Further, the two approaches of cabin sequestering method which were found promising in obtaining pure cultures of Phytophthora devoid of bacterial contamination, can also be employed to retrieve bacterial contaminated cultures of research significance.