PLANT GROWTH PROMOTING ATTRIBUTES OF PSEUDOMONAS FLUORESCENS ISOLATED FROM RHIZOSPHERE OF RICE IN RANGAREDDY DISTRICT

摘要

Rice is an economically important food crop, which is subjected to infect by a host of fungal, viral and bacterial pathogens. Plant growth-promoting rhizobacteria (PGPR) are beneficial bacteria that colonize plant roots and enhance plant growth by a wide variety of mechanisms. The use of PGPR is steadily increasing in agriculture and offers an attractive way to replace chemical fertilizers, pesticides and supplements. Pseudomonas fluorescens is important among PGPR because it is having an ability to induce plant growth as well as control the growth of pathogens. In the present study thirty P. fluorescens isolates were isolated, from the rhizospheric soils of rice fields from the Rangareddy district of Telangana state and the isolates were screened and characterized for the PGPR characters like phosphate solubilisation, ammonia and Indole Acetic Acid (IAA) production. Isolates showing PGP properties were further screened in vitro for biocontrol activities like siderophore, HCN and antagonism against soil borne phytopathogen Rhizoctonia solani causing sheath blight in rice. Results revealed that all isolates reacted positively for Ammonia production, HCN production and 23 isolates showed phosphate solubilisation and siderophore production, 28 showed IAA production. In vitro antagonism was shown by all isolates and high prevalence of antagonism was found against the fungal pathogen Rhizoctonia solani by the isolate DMP1 (53.43%) followed by DBP (51.53%). Results revealed that rhizospheric soils are the rich source of Pseudomonas fluorescens, which have a potential to be used as a biocontrol agent.