Study of the effect of consortia of PGPR on the growth of Trichosanthes cucumerina in a hydroponic system

Abstract: Hydroponics is the method of growing plants using soil-less cultivation systems. Plant growth-promoting bacteria are the rhizosphere bacteria that help plant growth and suppress plant diseases. In this study, we have isolated PGPR from the hydroponic systems and tested the efficacy of a consortium on the growth of Trichosanthes cucumerina. Ten organisms were isolated from a pre-set hydroponic system, of which three were selected based on their plant growth-promoting abilities. The isolated strains were identified as Chryseobacterium jejuense, Pseudomonas oryzihabitans and Sphingomonas paucimobilis. These isolates produced high levels of indole-3-acetic acid as well as other plant growth-promoting factors such as cellulase, pectinase, and siderophore production. All three isolates showed biofilm formation and growth in nutrient solutions with high EC values, indicating their ability to adhere to plant root surfaces and survive in nutrient solutions to promote plant growth. A consortium of these organisms used in the deep-water hydroponic system of T. cucumerina showed a significant increase in the number of leaves and root mass compared to control plants. Since these PGPR isolates exhibited multiple traits beneficial to the host plant, it has opened new possibilities for commercial application of these isolates in the hydroponic systems.