Designing a microbial synthetic community for improvement of drought stress tolerance in maize plants

Abstract

Severe climate change episodes such as prolonged drought or high temperatures negatively impact agricultural crops and place global food production at risk. In recent years, different research fields have been focused on developing technologies capable of sustaining crop productivity under environmental stresses. Among these technologies, the use of beneficial microorganisms has emerged as a promising tool to mitigate the effect of climate changes in plants. In this context, our research group evaluated the bacteria and fungi associated with a variety of sugarcane in a search of bacteria that promote drought tolerance in plants. Our results revealed a group of bacteria extremely efficient in colonizing plant organs and that remains in high abundance throughout the plant development. These microorganisms were isolated and applied as a synthetic microbial community for inoculations assays. Inoculcation of the synthetic community in maize plants was able to increase plant biomass by up to 3 times when compared to non-inoculated plants. The synthetic community also increased drought tolerance in maize and Brachypodium plants. Interestingly, genome sequencing revealed that the bacteria comprising the synthetic community do not harbor commonly investigated plant-growth promoting features in bacteria. We propose to investigate the mechanisms by which this synthetic community is capable of promoting drought tolerance in plants. We will perform inoculation trials in different commercial varieties of maize under drought stress in greenhouse and in field conditions. Inoculated and non-inoculated plants will have their productivity evaluated. The molecular mechanisms involved in drought tolerance induced by the synthetic community will be investigate by analyzing the differential gene expression profile of inoculated and non-inoculated plants.