Characterization of plant growth promoting bacteria and their tolerance to agrochemical Chlorpyrifos

Abstract

newline Plant growth promoting bacteria (PGPB) are group of beneficial bacteria which newlineboosts plant nutrition and productivity by multiple mechanisms such as solubilisation newlineof mineral nutrients like nitrogen and phosphorus, stimulation of root growth through newlineproduction of phytohormones, and suppression of root diseases through secretion of newlinevarious chemicals like antibiotics, HCN and allelochemicals. PGPB which have the newlineability to colonize area surrounding plant roots are called plant growth promoting newlinerhizobacteria (PGPR). Explicit use of pesticides which is used for protection of plants newlineagainst various types of pests has resulted in widespread contamination of newlineenvironment. Chlorpyrifos (CP) is one such example of pesticide, in the category of newlineinsecticide which damages non targeted organisms, disturbs microflora of soil newlineultimately leading to detrimental effect on plant. In view of above problem, the newlinepresent study had investigated the isolation of PGPB which possibly will enhance not newlineonly the plant growth but also tolerate or degrade redundant pesticide CP. Altogether newline49 bacterial isolates were isolated from different types of plant rhizospheric soil newlinesample All isolates were screened for four potential PGPB traits i.e. nitrogen fixation, newlinephosphate solubilisation, indole acetic acid (IAA) production and siderophore newlineproduction and results revealed that 42 isolates showed either or combinations of newlineselected plant growth promoting characters and 7 isolates failed to show any one of newlinethese four plant growth promoting characters. Five isolates i.e. R-1, O-2, T-1, T-2 and newlineE-2 which were showing all the four properties of plant growth promotion were newlinechosen to study their effect on growth parameters of rice plant. Inoculation of rice newlineseedlings with all the five bacterial isolates showed an enhanced shoot length and newlineaverage fresh weight of shoot when tested in suitable season of paddy cultivation.