Exploitation of indigenous fluorescent pseudomonads for the management of wilt of chickpea caused by Fusarium oxysporum f. sp. ciceris

Abstract

Chickpea wilt caused by Fusarium oxysporum f. sp. ciceris is a devastating soil-borne disease with a significant impact on yields and affecting chickpea production worldwide. Fluorescent pseudomonads are utilized as effective biocontrol agents (BCA) against a variety of phytopathogens and they play a key role in pathogen suppression through various processes. In the present study, twenty indigenous fluorescent pseudomonads were isolated from twenty soil samples collected from different districts of North Eastern Karnataka. The isolates were tested in vitro for their ability to resist the pathogen by using a dual culture approach. Further, morphological and biochemical characters were studied by growing these isolates on King’s B agar medium. All twenty isolates showed inhibition of the test pathogen, with isolate PF-19 showing the highest inhibition of 88.89%. All the isolates developed slimy, irregular colonies with light yellowish green pigmentation, fluorescence under UV light and rod-shaped cells under the microscope, as well as gram negative in reaction. All isolates except PF-2, Pf-9 and PF-10 revealed positive results for KOH, catalase, gelatin liquefaction and starch hydrolysis.