Biochemical Characterization of Microsymbionts Associated with Zornia gibbosa Span. in Central Aravalli Range

Abstract

In current scenario, with increasing world population there is a strong demand to enhance crop productivity to feed the population. Characterization of indigenous rhizobia is very crucial for developing biofertilizers tailored to local climatic conditions, with the goal of increasing food production without excess use of chemical fertilizers. In the present investigation 44 root nodule bacterial strains or microsymbionts were isolated from root nodules of Zornia gibbosa growing in Central Aravalli region. These isolated RNB strains were examined for their phenotypic and biochemical activities such as salt tolerance, pH tolerance, bromo thymol blue (BTB) reaction, catalase activity, oxidase activity, cellulase activity, amylase production, indole production, citrate utilization and gelatin hydrolysis. All tested isolates showed significant diversity in their phenotypic and biochemical activities. The majority of the strains were limited to a tolerance of up to 3% NaCl concentration; however, strains Z2, Z13, Z14, Z15, Z21, and Z22 demonstrated tolerance up to a 5% NaCl concentration. A total of 29 isolates were able to grow within the pH range of 5-10. Few isolates showed positive results for citrate utilization (Z4, Z18, Z22, Z32 and Z44) and amylase production (Z4, Z6, Z21, Z25 and Z42). In this study only one isolate Z22 showed indole production. Conversely, when assessing various enzyme activities such as cellulase, catalase, protease, and gelatinase, all the isolates demonstrated considerable diversity. This type of study is essential for developing superior biofertilizers containing indigenous bacterial strains to enhance production.