Isolation of Endophytic Bacteria for Biological Control of Wilt Pathogens

Abstract

Twentyfive endophytic bacteria were isolated from internal tissues of root and stem portions of chickpea, sunflower, niger, chilli and capsicum plants. The endophytes were screened in dual culture on Potato Dextrose Agar (PDA) and Tryptic Soya Agar (TSA) against Fusarium oxysporum f. sp. ciceri, Fusarium udum, Rhizoctonia solani and Sclerotium rolfsii . Ten isolates exhibited inhibition of the pathogens. Maximum percent inhibition (37.93) of F. oxysporum f. sp. ciceri was obtained on PDA with B. subtilis (PDBCEN 3). On TSA percent inhibition was maximum (52.21) with isolate PDBCEN-7. Testing against F. udum in dual culture test revealed that Pseudomonas sp. (PDBCEN 8) showed maximum (40.45%) inhibition on PDA. Pseudomonas sp. (PDBCEN-2) was highly effective on TSA and showed maximum (56.9%) inhibition zone. Against R. solani , maximum inhibition (44.96%) was recorded with endophyte PDBCEN 7. On TSA all the ten endophytic bacteria were effective in restricting the growth of test fungus. Percent inhibition of S. rolfsii was maximum (40.93%) with Pseudomonas sp. (PDBCEN 6) on PDA. On TSA percent inhibition was maximum (46.73%) with P. fluorescens (PDBCEN 1). The endophytic isolates were able to promote better growth of chickpea but the vigour index varied between the isolates. We could not correlate high pathogen inhibition under in vitr o with high vigour index.