Plant Stress (Dec 2023)
Fostering plant resilience to drought with Actinobacteria: Unveiling perennial allies in drought stress tolerance
Abstract
As climate change exacerbates drought conditions, global crop production faces an escalating threat. Fortunately, an eco-friendly solution lies in harnessing the potential of plant-associated plant growth-promoting bacteria. However, it's crucial to recognize that drought's impact extends beyond plants; it also influences the composition, abundance, and activity of bacterial communities. Amongst these root-associated bacterial communities, Actinobacteria are key players in preserving the well-being of plant hosts during drought stress, with research demonstrating minimal disruption to these communities under drought conditions. Actinobacteria, found ubiquitously, are exceptional candidates for promoting plant growth due to their prevalence in soil and the rhizosphere, their adeptness at colonizing plant roots and surfaces, and their capability to produce diverse secondary metabolites under drought stress. With these attributes, members of the Actinobacteria phylum present themselves as the most promising candidates for microbial inoculation of plants. They are enriched in the rhizosphere and endosphere microbiomes of crops enduring water deficit stress conditions. Notably, Actinobacteria, particularly the Streptomyces genus, employ various mechanisms, such as the modulation of phytohormone levels, reinforcement of antioxidant enzymes, enhanced water and nutrient uptake, and more, to alleviate water deficit stress in crops. This comprehensive review explores actinobacterial diversity associated with plants and delves into the impact of drought stress on the diversity of the Actinobacteria. It also examines the mechanisms through which Actinobacteria mitigate drought stress in plants. Emphasizing the role of multi-omics techniques in broadening our understanding of plant-Actinobacteria interactions, this review aims to inspire further exploration in this relatively uncharted research territory. Furthermore, it discusses future research directions for the application of Actinobacteria with plant growth-promoting traits, underlining their potential for sustainable agricultural practices.
