Impact of chlorpyrifos on plant growth promoting rhizobacteria isolated from Abelmoschus esculentus

Abstract

Chlorpyrifos (CP), an organophosphate insecticide, is massively used in agriculture for protecting cereal and vegetable crops from various types of pests. Its persistence and toxic nature towards non-target organisms has ensued in widespread contamination causing noxious effect on terrestrial and aquatic living entities including humans. Change in soil microflora biodiversity due to excessive CP use is a major concern nowadays as it will affect soil fertility ultimately leading to detrimental effect on plant health and yield. In the present study impact of CP on PGPRs from Okra (Abelmoschus esculentus) plant has been tested. Three bacterial isolates O-1, O-2 and O-3 were isolated, all showing either or combinations of selected plant growth promoting characters such as nitrogen fixation, phosphate solubilisation, IAA production and siderophore production. O-2 isolate was showing all the four selected plant growth promoting traits. Effects of CP (RADAR 20® EC) on growth of three isolates were checked on Luria Bertani (LB) agar and M9 minimal medium (M9MM) salts supplemented with CP (50, 500 and 5000 mg/L). O-1 and O-2 grew on LB agar and M9MM agar media supplemented with 50, 500 and 5000 mg/L CP revealing their tolerance to CP. O-2 isolate after repeated field trial and biodegradation study, can prove as potential candidate for PGPR possessing potential of bioremediation of pesticide (chlorpyrifos) contamination as well.