Vol. 11, Issue 3 (2022)

Author(s):
Aradhana Sukhwal, Ravindra Meena, Devendra Jain, Ram Hari Meena and Gajanand Jat

Abstract:
Zinc is a very crucial micronutrient for crop plants that plays many important functions in their life cycle. Plant growth, development, maturity, vigor, and yield are directly or indirectly affected by zinc. The present study was conducted to isolate and characterize zinc solubilizing bacteria (ZSB) from different rhizospheric soil collected from different crop rhizosphere. ZSB proficiently solubilized both the insoluble zinc compounds although ZnO was effectively solubilized in comparison to ZnCO₃ and ZnPO₄. The soluble Zn concentration was determined in the culture supernatant using atomic absorption spectrophotometer (AAS). In broth assay, ZSB24 showed high solubilization range in zinc oxide 83.2 mg Zn/l and followed ZSB14 with a value of 68 mg Zn/l. A positive correlation between Zn solubilization and reduction in pH of the culture medium was also noted for most of the ZSB isolates. These 32 Zinc solubilising bacteria were subjected to morphological, physiological and molecular characterization, screening of their plant growth promotion activities, ability of these isolates to survive in abiotic stress conditions viz., salt, pH, drought, antibiotic and temperature stress. The results revealed that all the ZSB isolates were gram negative. The molecular diversity by Amplified Ribosomal DNA Restriction Analysis (ARDRA) was done in thirty two ZSB strains revelled high diversity amongst them. Based on UPGMA clustering analysis, the strains showed significant molecular diversity and the dendogram obtained differentiated 32 strains into 02 major clusters. The Major clusters were further sub divided into four sub clusters. Major cluster A consisted a total 27 strains and sub cluster A1 consisted of 3 strains, A2 consisted of 24 strains and cluster B consisted of 02 strains and 3 strains (ZSB20, ZSB29 and ZSB5) stood apart and were kept as independent minor groups in the dendogram.