Plant growth promotion and antifungal activities of the mango phyllosphere bacterial consortium for the management of Fusarium wilt disease in pea (Pisum sativum L.)

Abstract

Root rot caused by the pathogen Fusarium oxysporum is the number one cause of pea plant (P. sativum L.) death. There are many potential advantages to using rhizobacteria, endophytic bacteria and phyllospheric bacteria for managing plant diseases and promoting plant growth. This study investigated the potentiality of consortium species of bacteria to suppress root rot disease and their ability to promote the growth of pea plants compared with their individual and control plants. A total of 55 phyllospheric bacteria were isolated from mango flower and Bacillus sp. LBF- 02, Bacillus sp. LBF- 03 and Bacillus sp. LBF- 05 showed the most potent antimicrobial activity against root rot pathogens in a dual culture assay. Identification of phyllobacterial strain LBF- 01, LBF- 03 and LBF-05 were done by 16S rDNA sequence analysis using 704f forward primer (50-AGATTTTCCGACGGCAGGTT-30) and 907r reverse primer (50-CCGTCAATTCMTTTRAGTTT-30) with the PCR conditions. Their ability to solubilize phosphate, produce ammonia, siderophore and indole acetic acid, as well as produce extracellular enzymes in vitro was excellent. The results of a greenhouse study found that pea seed treated with consortium isolate significantly increased high germination rates and vigour indexes, as well as shoot and root length, fresh and dry weights, as compared with seed treated with single isolate and control. The defense enzyme activities in consortium treated pots were higher than those in individual and control pots. The plants treated with consortium exhibited higher levels of chlorophyll and carotenoids content in their leaves compared to the untreated control and single treated plants. A significant variation in the chemical profile of pea plants was found (F7,16 ? 2.598; P ? 0.048) resulting from different treatments (T1-T8). After evaluating a variety of growth and microbiological parameters, it was concluded that inoculation with the microbial consortium contributed to raising healthy and vigorously growing pea seedlings in greenhouse conditions, which is applicable in the field in future for sustainable farming.