Isolation and Characterization of Native Isolates of Silicon Solubilizing Bacteria from Rhizospheric Soil of Paddy (Oryza sativa L.) of Kolhapur District

Abstract

Paddy (Oryza sativa L.) is the most important cereal crop in the world and consumed as the major staple food by nearly 50% of the world population. India being the second largest producer and the largest exporter of rice worldwide; its production plays an important role in contributing to the national economy and meeting the demands of the rising population. Silicon is a beneficial element for the growth and productivity of paddy, containing upto 10% of its dry matter weight. Although silicon is found abundant in earth’s crust but it is not present in the available form. Silicon solubilizing bacteria found to play an effective role in soil by solubilizing insoluble form of silicates into bioavailable form of silica ultimately making it available to the crop. In the present investigation, twenty-two rhizospheric soil samples of paddy were collected from seven tehsils of Kolhapur district. Four isolates of silicon solubilizing bacteria were obtained. All the isolates were identified on the basis of morphological, microscopic observations and different biochemical tests. Biochemical tests were studies viz., methyl red test, nitrate reduction test, starch hydrolysis test, catalase test, indole production test, oxidase test and gelatine hydrolysis test. Most of the isolates showed positive while some showed negative test. All the isolates were rod shaped having irregular colony shapes. The isolates showed variability in Gram reaction, colony colour, margin and elevation. Out of the four SSB isolates, SSB-1 showed the highest solubilization index (3.13) and found to be most efficient in its role. The results advance our knowledge of the microbial diversity of silicon solubilizing bacteria in the rhizosphere of paddy and could guide the creation of biofertilizers with potential isolates in the future.