Native rhizobacteria improve drought tolerance in tomato plants by increasing endogenous melatonin levels and photosynthetic efficiency

Abstract

Global food productivity is a growing concern due to increasing agricultural losses caused by biotic and abiotic stresses. Drought is one of the biggest threats to crop productivity. A promising alternative to maintain crop yields is the use of plant growth promoting rhizobacteria (PGPR). A recently found phytohormone produced by PGPR, melatonin, has an important role in the tolerance of plant to abiotic stress. The aim of this study was to evaluate the effects of the inoculation with Pseudomonas 42P4 and Enterobacter 64S1 on the growth, biochemical, and physiology of tomato plants under drought stress. The results showed that PGPR inoculation increased growth parameters, total chlorophyll content, and chlorophyll fluorescence parameters of tomato plants under drought stress. Native PGPR inoculation increased endogenous melatonin and the accumulation of proline levels and reduced lipid peroxidation, thus improving the drought tolerance of tomato plants. The findings of this study suggest that these native strains are able to reduce the impact of drought and could be a potent alternative to maintain crop productivity.