A transient decrease in reactive oxygen species in roots leads to root hair deformation in the legume–rhizobia symbiosis

Authors

  • Dasharath Prasad Lohar,

    1. Department of Plant Biology, University of Minnesota, 250 Biological Sciences Building, 1445 Gortner Avenue, Saint Paul, MN 551088, USA
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  • Sajeet Haridas,

    1. Department of Plant Biology, University of Minnesota, 250 Biological Sciences Building, 1445 Gortner Avenue, Saint Paul, MN 551088, USA
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  • J. Stephen Gantt,

    1. Department of Plant Biology, University of Minnesota, 250 Biological Sciences Building, 1445 Gortner Avenue, Saint Paul, MN 551088, USA
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  • Kathryn A. VandenBosch

    1. Department of Plant Biology, University of Minnesota, 250 Biological Sciences Building, 1445 Gortner Avenue, Saint Paul, MN 551088, USA
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Author for correspondence: Kathryn VandenBosch Tel: +612 624 2755 Fax: +612 625 1738 Email: vande102@umn.edu

Summary

  • • A possible role for reactive oxygen species (ROS) in root hair deformation in response to Nod factor (NF) was investigated using Medicago truncatula nodulation mutants, and an inhibitor and precursors of ROS.
  • • In wild-type roots, ROS efflux transiently decreased approximately 1 h after NF treatment. Transcript accumulation of two NADPH oxidase homologs, respiratory burst oxidase homolog 2 (MtRBOH2) and MtRBOH3, also transiently decreased at 1 h. However, in the nonnodulating mutant Nod factor perception (nfp), transcript accumulation did not change.
  • • Exogenous application of ROS prevented root hair swelling and branching induced by NF. When accumulation of ROS was prevented by diphenylene iodonium (DPI), NF did not induce root hair branching. Root treatment with DPI alone reduced ROS efflux and induced root hair tip swelling. Transient treatment of roots with DPI mimicked NF treatment and resulted in root hair branching in the absence of NF. A transient DPI treatment did not induce root hair branching in the nonlegumes Arabidopsis thaliana and tomato (Lycopersicon esculentum).
  • • The results suggest a role for the transient reduction of ROS accumulation in governing NF-induced root hair deformation in legumes.

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