AUTHOR=Poudel Mousami , Mendes Rodrigo , Costa Lilian A. S. , Bueno C. Guillermo , Meng Yiming , Folimonova Svetlana Y. , Garrett Karen A. , Martins Samuel J. TITLE=The Role of Plant-Associated Bacteria, Fungi, and Viruses in Drought Stress Mitigation JOURNAL=Frontiers in Microbiology VOLUME=12 YEAR=2021 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.743512 DOI=10.3389/fmicb.2021.743512 ISSN=1664-302X ABSTRACT=

Drought stress is an alarming constraint to plant growth, development, and productivity worldwide. However, plant-associated bacteria, fungi, and viruses can enhance stress resistance and cope with the negative impacts of drought through the induction of various mechanisms, which involve plant biochemical and physiological changes. These mechanisms include osmotic adjustment, antioxidant enzyme enhancement, modification in phytohormonal levels, biofilm production, increased water and nutrient uptake as well as increased gas exchange and water use efficiency. Production of microbial volatile organic compounds (mVOCs) and induction of stress-responsive genes by microbes also play a crucial role in the acquisition of drought tolerance. This review offers a unique exploration of the role of plant-associated microorganisms—plant growth promoting rhizobacteria and mycorrhizae, viruses, and their interactions—in the plant microbiome (or phytobiome) as a whole and their modes of action that mitigate plant drought stress.