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Front. Plant Sci. | doi: 10.3389/fpls.2018.00188

Salicaceae Endophytes Modulate Stomatal Behavior and Increase Water Use Efficiency in Rice

  • 1School of Environmental and Forest Sciences, University of Washington, United States
  • 2Department of Biology, University of Washington, United States

Previous studies demonstrated that bacterial and yeast endophytes isolated from the Salicaceae family promote growth and alleviate plant stress. To determine the physiological pathways through which endophytes affect host plant water relations, we investigated plant water potential, water use, and stomatal responses of rice plants to endophyte inoculation under CO2 enrichment and water deficit conditions. We found decreases in stomatal conductance during the daytime and decreases in stomatal density of rice by endophytes. In addition, we observed increases in ABA concentrations in rice leaves with endophytes, which supports the impacts of endophytes on the stomatal responses. Due to the stomatal responses, accumulated total transpiration over time was significantly decreased by endophytes while biomass was either maintained or slightly increased. These led to increases in water use efficiency of the plants at harvest. Three different endophyte strains produced the same results in host plant water relations and stomatal responses. These stomatal responses were also observed under elevated CO2 conditions, and the increase in water use efficiency was greater under water deficit conditions. This increase in water use efficiency was positively correlated to daily light integral during the experiments. Our results provide physiological mechanisms of endophytes increasing water use efficiency. We suggest that the main reason was stomatal closure and alteration of stomatal density while photosynthesis might not be affected.

Keywords: Endophytes, rice, Stomatal conductance, water potential, water relations, Water use efficiency, water deficit, ABA

Received: 15 Nov 2017; Accepted: 31 Jan 2018.

Edited by:

Ying Ma, University of Coimbra, Portugal

Reviewed by:

Guzel Kudoyarova, Institute of Biology, Russia
Peter Schröder, Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt, Germany  

Copyright: © 2018 Rho, Van Epps, Wegley, Doty and Kim. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Soo-Hyung Kim, University of Washington, School of Environmental and Forest Sciences, Seattle, 98195-2100, WA, United States, soohkim@uw.edu