Morphological and biochemical characterization of fluorescent Pseudomonads from groundnut rhizosphere

Groundnut is an important grain legume and oil seed crop grown all over the world. Fluorescent Pseudomonads are beneficial bacteria that inhabit the root zone of plants and increase the growth of plants by a wide variety of mechanisms. In our studies,, we have assessed the morphological and biochemical characteristics of 24 fluorescent pseudomonads isolated from groundnut rhizosphere collected from Rayalaseema region of Andhra Pradesh. All the Pseudomonas fluorescens (Pf) strains showed development of fluorescent pigments under UV light. Morphological studies indicated that they have displayed (i) rod-shaped, (ii) smooth shiny surface, (iii) gram-negative reaction (iv) motility and (v) growth even at 41°C. None of the strains were positive for the indole, and voges-proskauer test. All strains were positive for oxidase, citrate, catalase, and gelatin liquefaction test; 58% were starch hydrolysis-positive, 29.16% were methyl red-positive and 62.5% were H₂S-positive. The present study proved that these Pf strains have potential plant growth-promoting activities. Our future studies are directed in establishing the plant growth-promoting effects of these Pf strains under Greenhouse and field conditions on groundnut.