STUDYING THE INTERACTION CHARACTERISTICS BETWEEN PLANT AND SOME ASSOCIATED RHIZOSPHERE MICROORGANISMS

Abstract

The present study deals with the interactions between Sorghum [Sorghum bicolor (L.) Moench] plants and their associated rhizomicrobes and the impact of these interactions upon sorghum growth parameters. Both growth promoting activity of the isolates upon Sorghum germination and seedling growth beside antifungal activity of the isolates were investigated. The potential of the isolates were characterized for the production of indole-3-acetic acid (IAA), phosphate solubiliztion ability and some lytic enzymes activity as functional potentialities correlated with plant growth promoting activities. Consequently, the isolates were identified by 16S ribosomal RNA by sequencing analysis. The results showed that most isolates produced IAA and the highest amount of IAA was detected from Bacillus megaterium, which produced 3.50 µg/mL and Pseudomonas geniculata that produced 3.23 µg/mL. Sorghum plants inoculated with selected rhizobacterial strains were significantly enhanced specially by Pseudomonas geniculata (SC), Rhizobium pusense (SD), Bacillus cerues ATCC 14579 (S4) and Bacillus cerues X3 ( S2). Whereas, the mineral contents (Mn, Fe, Cu, Zn, N, P and K) were significantly higher values in the shortest plant shoot and lowers in the higher shoot of sorghum plants. Meanwhile, sorghum parameters of photosynthetic pigments, amino acids and N, P, and K concentrations were increased significantly as compared with untreated control. Consequently, the more efficient isolates were identified as Rhizobium pusense, Bacillus cerues X3 and Bacillus cerues ATCC 14579, respectively.