Growth enhancement and rhizosphere colonization of Chilli (Capsicum annuum) by Enterobacter hormaechei.

Enterobacter is a genus of Gram negative, facultative anaerobic, rod-shaped bacteria, characterized by highly variable genome, pathogenic opportunism, antibiotic resistance and ability to form biofilms. Many species of Enterobacter have plant growth-promoting properties and are therefore, of magnificent importance in agriculture. Moreover, it has been reported that Enterobacter can improve and strengthen tolerance levels of abiotic stress in plants growing in saline conditions. Besides directly promoting growth, development and morphogenesis of plants by synthesizing plant hormones, iron carriers and aminocyclopropane carboxylic acid deaminase, they are known to produce antibacterial substances which prevent colonization of undesirable bacteria in the rhizosphere. Their ability to fix nitrogen not only directly encourages plant growth but their activities also affect the community of existing nitrogen fixing bacteria in the rhizosphere. The study demonstrated that Enterobacter hormaechei when applied along with Bacillus luti and Bacillus paramycoides showed excellent growth of chilli plants. Moreover, when they were combined with vermicompost, the vegetative & reproductive growth of the plants significantly augmented. Interestingly, the study also showed that Enterobacter hormaechei can coexist with other microorganisms and exhibit synergism. The study also clearly indicates the ability of Enterobacter hormaechei to produce conspicuous amounts of auxin and gibberellin. Besides its ability to solubilize zinc, Enterobacter hormaechei has a potential phosphate and potassium solubilizing ability which further makes it a suitable plant growth promoting rhizobacteria. The cross-section of the roots showed the colonization of Enterobacter hormaechei in the endosphere, which suggests that it directly manipulates the plant growth.