Ecology, Environment and Conservation Paper

ASSESSMENT OF PSEUDOMONAS SPP. FOR GROWTHPROMOTION, BIOCONTROL AND STRESS TOLERANCEAPPLICABILITY TOWARDS ORGANIC AND INORGANICPOLLUTANTS

Sonam Shaheen, Nivedita Mishra and S. Krishna Sundari

Abstract

Organic and inorganic pollutants have deleterious effect in the environment, crops productivity, microbiomeand soil fertility. The persistence uses of toxic compound like pesticides not only affect soil health but alsoagitated ecosystem. Use of Plant Growth Promoting rhizobacteria can play an important role towardsachieving the objectives of sustainable ecosystem. Pseudomonas group of bacteria are known for theirremediation properties but are lesser explored for their growth promotion attributes and to alleviate otherabiotic and biotic stress in the agriculture system. The paper presents multifarious potential of Pseudomonasisolates obtained from agriculture fields in the vicinity of Ghaziabad, U.P (PGPM2, 3, 4, 5). Biochemicaltests for identification suggested that these isolates belong to Pseudomonads group of organisms. Further,molecular characterization through 16S RNA gene sequence analysis confirmed their identity as PGPM2-Pseudomonas species, PGPM3- Pseudomonas plecoglosida, PGPM4- Pseudomonas and PGPM5- Pseudomonasrespectively. Production of essential hormones such as indole acetic acid, gibberellic acid and phosphatesolubilisation activity have endorsed the plant growth promotion attribute by these isolates. Production ofammonia and secretion of lytic enzymes like lipase by PGPM2 and PGPM3 indicate stronger bio-controlabilities in these isolates as compared to other isolates, all isolates showed positive for the bio-film formation,a positive attribute that helps in colonising and surviving harsh environments. Bangle method establishedthe strong antagonistic activity that these isolates possess against 3 important plant root pathogens namelyMacrophominaphaseolina (41%) followed by Sclerotium rolfsii (36-15%) and Fusarium oxysporum (21%)respectively. Isolates PGPM2 & PGPM3 showed maximum tolerance against salt (500MM) while isolatesPGPM2 and PGPM4 showed better tolerance to Pesticides monocrotophos and dimethoate (PGPM2- MICand LD50 and PGPM3 –MIC AND LD50). Host plant bioassay with pearl millets (bajra) revealed maximumgrowth promoting efficiency (root length and shoot length) by PGPM2. The manuscript provides abiochemical and physiological evidence that native Pseudomonas isolates not only promote plant growthbut also possess unique ability to tolerate adverse abiotic stress conditions such as tolerance to salt, organic(pesticides) and inorganic pollutants thus offering multiple growth supporting advantages to the planthost.