R. Rangeshwaran ¹, J. Raj ², Sreerama Kumar ¹

Affiliations
1 Biological Control, Post Bag No. 2491, H. A. Farm Post, Bellary Road, Bangalore - 560024, Karnataka, IN
2 Department of Agricultural Microbiology, University of Agricultural Sciences, Bangalore - 560065, Karnataka, IN

Abstract

Five endophytic bacteria were isolated from healthy chickpea (Cicer arietinum L.) plants by surface-disinfestation method and identified based on morphological, physiological and biochemical tests. Erwinia herbicola and Enterobacter agglomerans, which had nitrate-solubilizing ability, were isolated from the ischolar_main endosphere and Bacillus megaterium, B. circulans and one unidentified species of Bacillus were isolated from the leaf and stem tissues. None of the isolates had phosphate-solubilizing ability. All the isolates tolerated a wide range of pH and exhibited growth from pH 5 to 9. B. circulans and E. agglomerans tolerated an alkaline pH of 11, which is unusual. Higher growth promotion was noticed in chickpea plants treated with B. megaterium, E. agglomerans and Bacillus sp. and the plants treated with endophytes survived well in the presence of the wilt pathogen, Rhizoctonia solani. Seedlings from seeds treated with bacteria showed an increase in phenol content up to sixth day after Inoculation. The maximum phenol content (483.33μg g⁻¹) was noticed in B. megaterium treated and the lowest (246.67μg g⁻¹) was in control. Endophytic bacteria from healthy plant tissue could play a useful role In plant protection.

Keywords

Chickpea, Endophytic Bacteria, Growth Promotion, Identification.

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R. Rangeshwaran ¹, J. Raj ², P. Sreerama Kumar ¹

Affiliations
1 Biological Control (ICAR), H. A. Farm Post, Hebbal, Bellary Road, Bangalore, 560 024, Karnataka, IN
2 Department of Agricultural Microbiology, University of Agricultural Sciences, Bangalore, Karnataka, IN

Abstract

Five chickpea (Cicer arietinum) endophytic bacteria, identified as Erwinia herbicola, Enterobacter agglomeraus. Bacillus megaterium and Bacillus sp. and Bacillus circulans were tested for intrinsic antibiotic resistance in order to see if endophytes showed variation in resistance to antibiotics. The resistance pattern was compared with two rhizospheric bacteria viz. Psendomonas fluoresceus and B. subtilis in order to see if the susceptibility of endophytes differed with that of bacteria isolated from rhizosphere. The endophytes seemed to be less resistant to antibiotics. B. circulaus was susceptible to all antibiotics tested except amoxycillin (10μg). However B. megaterium and Bacillus sp, and E. agglomeraus showed some resistance, P. fluorescens and B. subtilis showed resistance to a wide range of antibiotics indicating that they could be better competitors in the rhizosphere. Preliminary screening was done to monitor B. megaterium and Bacillus sp. by using the observed antibiotic resistance. Out of the 25 ischolar_main/stem/leaf tissues tested, 10 tested positive for the presence of B. megaterium and 11 for Bacillus sp. However, they coutd not be reisolated from the stem tissue, 3 and 2 of the leaf samples showed presence of B. megaterium and Bacillus sp., respectively.

Keywords

Antibiotics, Endophytic Bacteria, Resistance Pattern.

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