Potential Microbial Consortium Mitigates Drought Stress in Tomato (Solanum lycopersicum L.) Plant by Up-regulating Stress-Responsive Genes and Improving Fruit Yield and Soil Properties

The present study is conducted for the growth and yield improvement of tomato plants under drought stress by inoculation of hexa plant growth-promoting microorganisms (PGPM). Hexa-PGPM consortium (Bacillus megaterium, Pseudomonas fluorescens, P. aeruginosa, P. putida, Paenibacillus polymyxa, and Trichoderma harzianum) is inoculated to the tomato plant, and growth attributes, membrane integrity, water status, accumulation of osmolyte, reactive oxygen species (ROS) scavenging capability, and the qRT-PCR analysis were performed for expression of stress-responsive DREB, APX, CAT, SOD, and P5CS under 80% and 40% moisture content of the field capacity. Soil physico-chemical and microbial properties were also evaluated. Our results revealed that under drought, hexa-PGPM consortium-inoculated plants exhibited lower cellular damage and better plant growth and yield than non-inoculated plants. Antioxidant enzyme catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX) activity decreases under drought stress condition and it increases in hexa-PGPM-inoculated plants. Simultaneously, the gene expression analysis showed up-regulation of a transcriptional activator (DREB1), osmolyte accumulators (P5CS), and ROS scavengers (CAT, SOD, APX) gene by application of hexa-PGPM consortium. Overall, the results showed that the hexa-PGPM application confers drought mitigation in tomatoes by altering different physico-biochemical and molecular parameters. In addition, the PGPM application also improved the soil's physical, chemico-chemical, and biological properties under drought stress conditions. The present study supports the application of hexa- PGPM consortium to elevate drought tolerance, yield, and soil fertility enhancement under drought stress as a low-cost agro-biotechnology tool and environment-friendly drought management techniques in tomato crops.

Automated summary

This study investigates the use of hexa plant growth-promoting microorganisms (PGPM) to improve the growth and yield of tomato plants under drought stress. The inoculation of hexa-PGPM consortium to the plants helps enhance plant growth, reduce cellular damage, and increase antioxidant enzyme activity. The gene expression analysis also shows up-regulation of stress-responsive genes. Moreover, the application of hexa-PGPM improves the physical, chemical, and biological properties of soil under drought stress conditions.