Pseudomonas veronii KJ mitigates flood stress-associated damage in Sesamum indicum L.

Physiological characteristics of terrestrial plants are severely affected by waterlogging stress, leading to low photochemical efficiency of leaves and retarded growth and development. Plant growth-promoting rhizobacteria contain the acdS gene, which encodes for the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase. ACC deaminase cleaves the substrate ACC to produce α-ketobutyrate and ammonia and mitigates the adverse effect of prolonged water stress. The aim of this study was to characterize ACC deaminase-producing rhizobacteria and evaluate their effects on sesame (Sesamum indicum L.) under waterlogging stress condition. The rhizobacterium Pseudomonas KJ was characterized on the basis of sequencing of the partial 1501 bp fragment of 16S rDNA amplicon and confirmed as Pseudomonas veronii KJ. ACC-supplemented minimal medium revealed the phenotypic identification of acdS gene. The nucleotide sequence (1001 bp) of ACC deaminase gene of P. veronii KJ was also confirmed. We used P. veronii KJ as a bioinoculant in waterlogging stress and monitored the growth and developmental characteristics of sesame plants, including leaf chlorophyll fluorescence signals, concentration of chlorophyll, root and shoot length, and fresh and dry biomass in stressed versus unstressed plants. Plants treated with P. veronii KJ significantly (P ≤ 0.05) mitigated the waterlogging stress-related damage. Thus, the rhizobacterium Pseudomonas veronii KJ may be considered as a commendable addition to the consortium of beneficial microbes for its ability to reduce waterlogging stress-related damage in sesame plants.