Modulating Drought Stress Response of Maize by a Synthetic Bacterial Community

Abstract

Plant perception and responses to environmental stresses are known to encompass a complex set of mechanisms in which the microbiome is involved. Knowledge about plant physiological responses is therefore critical for understanding the contribution of the microbiome to plant resilience. However, as plant growth is a dynamic process, a major hurdle is to find appropriate tools to effectively measure temporal variations of different plant physiological parameters. Here, we used a non-invasive real-time phenotyping platform in a one-to-one (plant–sensors) set up to investigate the impact of a synthetic community (SynCom) harboring plant-beneficial bacteria on the physiology and response of three commercial maize hybrids to drought stress (DS). SynCom inoculation significantly reduced yield loss and modulated vital physiological traits. SynCom-inoculated plants displayed lower leaf temperature, reduced turgor loss under severe DS and a faster recovery upon rehydration, likely as a result of sap flow modulation and better water usage. Microbiome profiling revealed that SynCom bacterial members were able to robustly colonize mature plants and recruit soil/seed-borne beneficial microbes. The high-resolution temporal data allowed us to record instant plant responses to daily environmental fluctuations, thus revealing the impact of the microbiome in modulating maize physiology, resilience to drought, and crop productivity.

Response of Plant-Associated Microbiome to Plant Root Colonization by Exogenous Bacterial Endophyte in Perennial Crops

“…In the non-inoculated roots, Firmicutes were the major taxa with strong cooperation among them. When the synthetic community derived from root endophytes was used for inoculation, an increase in the relative abundances of potential plant growth promotion microorganisms was detected ( Armanhi et al, 2021 ). We did not detect a large number of bacterial taxa differentially represented between inoculated and non-inoculated roots, but a number of taxa harboring plant beneficial microbes were among the most connected in the co-occurrence network of inoculated root microbiome.…”

“…et al, 2021 ). Moreover, the application of exogenous synthetic communities composed of naturally occurring, highly abundant plant-bacteria, becomes a new approach to increased biomass and enhanced root system development in agricultural crops ( de Souza et al, 2016 ; Armanhi et al, 2017 , 2021 ). However, achieving the full benefit of the application of BCAs, it is important to understand the extent of ecological effect of the introduction of exogenous microorganisms into environments and its impact on the host-plant over an extended period of time.…”

The Role of Synthetic Microbial Communities (SynCom) in Sustainable Agriculture

“…Inoculation with a SynCom constructed from sugarcane-associated microbes increased the biomass of maize plants compared to the uninoculated controls (Armanhi et al, 2018). The same SynCom also improved drought tolerance and reduced yield loss in maize (Armanhi et al, 2021). Another SynCom, composed of desiccation-tolerant bacteria, showed increased plant growth parameters such as dry weight of shoot and root, plant height, and plant diameter when compared with either non-inoculated control or mono-inoculated treatments (Molina-Romero et al, 2017).…”

“…The goal is to facilitate an increase in community stability through synergistic interactions between its members (de Souza et al, 2020). Several studies have been reported that SynCom application enhanced plant growth under greenhouse conditions (Armanhi et al, 2021;Chai et al, 2021;Lee et al, 2021) as well as field conditions (Santhanam et al, 2015;Wang et al, 2021).…”

“…To assess the SynCom performance on colonization and growth of maize(Armanhi et al, 2018), explore the bacterial traits associated with successful colonization of plants(de Souza et al, 2019) and study the impact of the SynCom on three commercial maize hybrids under drought stress(Armanhi et al, 2021) …”