Research Projects

Salinity is one of the major abiotic stress factors causing land degradation and loss in agricultural crop productivity. There are two conventional approaches to manage soil salinization viz. application of chemicals and plant growth promoting microbes (PGPM) in the form of bioinoculants. Application of inorganic compounds such as gypsum, calcium chloride, lime etc have been in practice to reduce salinity stress in agricultural fields. However, overuse of these chemicals may conversely lead to more soil salinization. An eco-friendly approach is the application of bioinoculants. But it suffers from some inherent challenges like competition with native microflora because of which it loses its efficacy and survivability. To overcome these challenges top-down rhizosphere engineering of plant-mediated indirect selection by adapting microbiome to various stresses is a potential, novel and sustainable strategy. It includes multiple passaging of microbiome, leading to artificial selection of specific microbial communities, which can confer beneficial phenotypic traits in host plants, including improvement in plant fitness and stress mitigation. The objective of this study is to mitigate salinity stress through such a top-down rhizosphere engineering approach followed by generation of synthetic microbial community (SMC) from the salt stress acclimatised microbiome. The hypothesis is that the plant will select a halotolerant rhizosphere microbial community during the process of acclimatisation, which will serve as an excellent bank for designing SMCs. This will be a robust strategy for application of indigenously selected microbiome, and will overcome the limitations of conventional bioinoculants by better promotion of plant growth under salinity stress without competing with indigenous microflora. For this work, the model plant system is tomato. Two tomato varieties has been considered to understand the impact of cultivar on acclimatisation process. Further, analysis of rhizosphere microbial community in both tomato cultivars at each plant growth cycles will reveal dynamics in microbial composition during the process of acclimatisation under salt stress condition. Moreover, designing of SMCs will be performed from a culture bank generated from the salt stress acclimatised microbiome. The efficiency of the developed SMCs will be tested first under controlled condition and then in field conditions. The novelty of this project is the strategic combination of top down and bottom up approaches of rhizosphere engineering; SMCs will be prepared with salt stress acclimatised microbiome, the latter being recruited by the plant, hence minimizing the competition with native microflora. The proposal will serve as a giant leap in understanding the basics of acclimatisation of microbiome towards repeated cycles of stress, as well as bring to light a novel rhizosphere engineering tool for agricultural sustainability.