Newswise — Using a microbe derived from the roots of desert plants to prime crop plants could prove to be a potent method for enhancing their drought resilience.
Germinating Arabidopsis (thale cress) and alfalfa with a microbe taken from the roots of a common desert plant has been shown to help them to thrive under drought conditions[1].
Heribert Hirt from KAUST emphasizes that mitigating the impact of drought on crop plants stands as a pressing objective for researchers in agricultural biotechnology. Collaborating with colleagues from Germany and across Saudi Arabia, including Khairiah Alwutayd, an assistant professor from Princess Nourah bint Abdulrahman University, they worked on the project together.
According to Hirt, the DARWIN21 desert initiative was initiated a decade ago at KAUST with the aim of isolating and studying desert microbes. Their aspiration is to transfer the beneficial traits exhibited by these microbes in desert plants to crop plants, endowing them with enhanced tolerance to heat, salt, and drought. Such advancements in crop resilience could play a significant role in bolstering global food security.
Within the framework of the DARWIN21 program, Hirt and his team have made substantial progress. They successfully isolated over 10,000 microbial strains from desert soils and the roots of desert plants. In their rigorous screening process, they germinated Arabidopsis plants using hundreds of these strains, aiming to identify the ones that notably amplify the plants' drought tolerance. This dedicated effort represents a crucial step towards finding potential microbial candidates that could bolster crop resilience to water scarcity.
In this specific study, the researchers focused on investigating the molecular mechanisms responsible for bolstering drought resilience in crop plants. To delve deeper into this area, they opted for a bacterium strain called SA190, derived from Pseudomonas argentinensis. This particular strain was sourced from the root nodules of Indigofera argentea, a small shrub-like plant naturally occurring in desert regions and dry shrublands stretching from the Sahara to India. By examining the interactions between SA190 and crop plants, the scientists aimed to unveil the underlying processes that lead to enhanced drought tolerance in these plants.
As Alwutayd points out, the advantage of using Arabidopsis in this study lies in its well-established status as the genetic model in plant biology. Due to our extensive knowledge of Arabidopsis, the researchers were able to conduct a detailed analysis of the specific molecular mechanisms and alterations induced by SA190 in response to drought. This knowledge-rich foundation enabled them to gain valuable insights into how SA190 enhances the plant's resilience to water scarcity at the molecular level, facilitating a deeper understanding of the beneficial effects of the microbial strain on crop plants.
The team found that SA190 modifies the epigenetic status of important drought stress genes. These genes are not expressed under good growing conditions, but are exclusively expressed when plants are exposed to drought.
Alwutayd highlights a crucial finding from the study: SA190 demonstrated a remarkable ability to activate specific genes in crop plants only when necessary, thus preventing any adverse impact on crop yields. This stands in contrast to certain drought mitigation methods that may inadvertently affect crop productivity. Additionally, SA190 actively influenced the root architecture of the plants, resulting in an improvement in the plant's water use efficiency. This means that the microbial strain enhanced the plant's ability to optimize water consumption, ultimately contributing to its improved resilience in drought conditions without compromising overall crop productivity.
The team then primed alfalfa with SA190, and these plants showed significantly enhanced drought resilience compared with controls.
Hirt emphasizes the practicality of utilizing SA190 on a larger scale. The microbial strain can be readily produced in substantial quantities using fermenters. The application process involves simply coating crop seeds with the SA190 microbes. When these coated seeds are sown in the fields, the SA190 naturally establishes a direct association with the crop seedlings. Importantly, this approach circumvents any competition with other soil microorganisms, ensuring the successful integration of SA190 with the crops. This straightforward and efficient method holds great promise as a potent tool for enhancing plant resilience to drought, offering a valuable contribution to drought resistance efforts in agriculture.
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