Isolation and Screening of Multifunctional Plant Growth Promoting Rhizobacteria from Rhizopshere of Different Crop Fields

Abstract

Rhizospheric bacteria are naturally occurring soil microbes that are aggressively found in the plant rhizosphere, at root surface and in association with roots. They give satisfactory benefit plants by several mechanisms such as nitrogen fixation, phosphate solubilization, potassium decomposition, IAA production, antagonism against phytopathogenic microorganisms by production of siderophore, antibiotics and cell wall degrading enzymes. The total number of beneficial bacteria were isolated from different rhizospheric soil in agricultural lands. The isolated bacterial strains were screened for their plant growth promoting factors such as production of ammonia, siderophore, cellulase, chitinase, and pectinase enzyme. All of the isolates produced ammonia and 79% of the isolates produced siderophore on chrome azurole S agar plates. Furthermore, the bacterial isolates produced cell wall degrading enzyme; pectinase (69%), cellulase (94%), chitinase (51%), amylase (61%) and glucanase enzyme (59%) on agar plate method. The isolates also produced auxin type plant hormone (IAA), all the isolates produced IAA and the highest IAA producing strain is W1 and the produce amount was 21.91mg/L. Among the isolated bacteria, only two strains could produce HCN with the use of Feigl-Anger paper method. The recent study suggests that the use of these PGPR isolates as inoculants might be a promising source for sustainable agricultural use.