Isolation of Pseudomonas Species from Rhizospheric Soil and its Antagonistic Effect on Plant Pathogen

Abstract

The pathogen attack on plants (such as tubers and small plants) has substantially progressed by 60% irrespective of even when the plants have strong immune system for the past five decades. It drastically affects the plant growth, yield and production. Certain pesticides and fertilizers have been tried to control the progressing pathogenic microorganisms. Although these measures have proved worthless due to the resistance shown by those pathogens and resulted in environmental pollution over a period of time. Bio control measures are well appreciated as it is ecofriendly. Antagonist microorganism (bacteria, fungi) will be used to suppress the growth of the invading pathogens. In this study, Pseudomonas species , were screened from rhisozpheric soill from the local region of Srivilliputhur. Eleven isolates from rhizospheric soil were screened and characterized by Gram staining, catalase test, Voges-Proskauer test, and oxidase test. The morphological studies of all the screened Pseudomonas isolates were observed as Gram negative. Further, all the isolates were found to be catalase positive and negative for VP test. The isolates were subjected to antagonistic effect on plant fungal pathogen such as Rhizoctonia solani. Among eleven Pseudomonas isolates four isolates showed antagonistic effect against R.solani. In the present investigation, four isolates showed potent antagonistic effect and could be used as effective bio-control agent against plant fungal pathogen R.solani.