Abstract

SCREENING OF RHIZOMICROFLORA ISOLATED FROM THE RHIZOSPHERE OF AEGLE MARMELOS FOR MULTIPLE PLANT GROWTH PROMOTING AND ANTIMICROBIAL ACTIVITIES

Damle N. R.* and S. W. Kulkarni

Abstract

The rhizosphere is the area of intense microbiological activity. The population of microorganisms differs qualitatively and quantitatively in the rhizosphere from plant to plant. So the rhizosphere may harbor some interesting organisms. As roots of Aegle marmelos are used as drug, the rhizosphere of Aegle marmelos may harbor various types of microorganisms. PGPR increase plant growth by various mechanisms like NH3, HCN, IAA, Siderophore production and PO4 solubilization. In the present study 21 bacterial isolates from the rhizosphere of medicinal plant Aegle marmelos were obtained and characterized on the basis of morphological, cultural and biochemical properties. All isolates were screened for various PGP activities. Interestingly out of 21 isolates 18 (85%) showed NH3 and IAA production within the range of 9-126μg/ml, 81% produced HCN, 33% produced siderophore and 57% solubilized PO4. Two isolates AM3 and AM9 were identified as Bacillus cereus and Bacillus pumilis respectively. AM3 was identified by PIBWin software and AM 9 by 16s rRNA and showed positive results for all 5 PGP activities. While isolate AMH2 showed 4 PGP activities. AM3 and AM9 isolates were selected further for seed germination and pot experiment. AM 3 and AM 9 showed 100% and 96% seed germination respectively, increase in plant height, root length, shoot length, fresh and dry weight as compared to control. Bacillus cereus, isolates AMH 2 and AM10 showed antibacterial activity against plant pathogen Xanthomonas axonopodis and Xanthomonas citri. So these isolates can be used as bio inoculants and bio controlling agents.

Keywords: Rhizosphere, PGPR, medicinal plants, antibacterial activity.