DisplayTitle

2R,3R-Butanediol, a Bacterial Volatile Produced by Pseudomonas chlororaphis O6, Is Involved in Induction of Systemic Tolerance to Drought in Arabidopsis thaliana

¹Department of Floriculture, Chunnam Techno College, Jeonnam 516-911, Korea; ²Jellanamdo Agricultural Research and Extension Services, Jeonnam 520-715, Korea; ³Department of Biology, Utah State University, Logan 84322-5305, U.S.A.; ⁴Department of Agricultural Biotechnology, Center for Fungal Genetic Resources, and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921, Korea; ⁵Department of Plant Biotechnology and Biotechnology Research Institute, Chonnam National University, Gwangju 500-757, Korea; ⁶Systems Microbiology Research Center, KRIBB, Daejeon 305-600, Korea

Root colonization of plants with certain rhizobacteria, such as Pseudomonas chlororaphis O6, induces tolerance to biotic and abiotic stresses. Tolerance to drought was correlated with reduced water loss in P. chlororaphis O6-colonized plants and with stomatal closure, indicated by size of stomatal aperture and percentage of closed stomata. Stomatal closure and drought resistance were mediated by production of 2R,3R-butanediol, a volatile metabolite of P. chlororaphis O6. Root colonization with bacteria deficient in 2R,3R-butanediol production showed no induction of drought tolerance. Studies with Arabidopsis mutant lines indicated that induced drought tolerance required the salicylic acid (SA)-, ethylene-, and jasmonic acid-signaling pathways. Both induced drought tolerance and stomatal closure were dependent on Aba-1 and OST-1 kinase. Increases in free SA after drought stress of P. chlororaphis O6-colonized plants and after 2R,3R-butanediol treatment suggested a primary role for SA signaling in induced drought tolerance. We conclude that the bacterial volatile 2R,3R-butanediol was a major determinant in inducing resistance to drought in Arabidopsis through an SA-dependent mechanism.

Additional keywords:abscisic acid, β-aminobutyric acid, guard cell, jasmonate, microbe-associated molecular patterns.