Population Dynamics and Diversity of Endophytic Bacteria Associated with Soybean (Glycine max (L) Merril).

ABSTRACT

Aim: Endophytic bacterial population and their diversity in soybean were investigated. Study Design: Endophytic population was assessed during different growth stages of soybean (CV JS 335) viz., vegetative and reproductive stages. Place and Duration of Study Microbiology Research Laboratory, Department of Microbiology, R. A. Mahavidyalaya, Washim (MS), India, during the cultivation period of June-December 2010. Methodology: Healthy plants of soybean were screened from the different locations of Washim district (M. S., India). Samples represent each growth stage viz., vegetative (V1- V5) and reproductive (R1-R8) were collected. Population densities were expressed as log10 colony forming units (CFU) g-1 fresh weight. The isolates were identified to genus level according to Bergey’s Manual of Determinative Bacteriology on the basis morphological, cultural and biochemical characteristics. Results: The maximum endophytic population was recorded for vegetative stage at V5 and V4 (5.74 and 5.01 log10 CFU g-1 fresh weight) and for reproductive stage at R2, R1 and R3 (5.84, 5.80 and 5.74 log10 CFU g-1 fresh weight). A total of 572 (35.50 %) from vegetative growth stages and 1039 (64.50 %) from reproductive growth stages bacterial isolates were obtained. The endophytic isolates were identified as members belonging to the genera Pseudomonas, Bacillus, Enterobacter, Klebsiella, Acetobacter Burkholderia, Rhizobium and Xanthomonas. Conclusion: As soybean development progresses endophytic population increased. At maturity, the high population density was observed and thereafter the population declined.