Transcription activator-like (TAL) effectors targeting OsSWEET genes enhance virulence on diverse rice (Oryza sativa) varieties when expressed individually in a TAL effector-deficient strain of Xanthomonas oryzae

Authors

  • Valérie Verdier,

    1. Department of Bioagricultural Sciences and Pest Management and Program in Plant Molecular Biology, Colorado State University, Fort Collins, CO, 80523-1177, USA
    2. Institut de Recherche pour le Développement, UMR Résistance des Plantes aux Bioagresseurs, IRD-CIRAD-UM2, Montpellier Cedex 5, France
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    • These authors contributed equally to this work.
  • Lindsay R. Triplett,

    1. Department of Bioagricultural Sciences and Pest Management and Program in Plant Molecular Biology, Colorado State University, Fort Collins, CO, 80523-1177, USA
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    • These authors contributed equally to this work.
  • Aaron W. Hummel,

    1. Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, USA
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  • Rene Corral,

    1. Department of Bioagricultural Sciences and Pest Management and Program in Plant Molecular Biology, Colorado State University, Fort Collins, CO, 80523-1177, USA
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  • R. Andres Cernadas,

    1. Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, USA
    2. Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, USA
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  • Clarice L. Schmidt,

    1. Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, USA
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  • Adam J. Bogdanove,

    1. Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, USA
    2. Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, USA
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  • Jan E. Leach

    Corresponding author
    • Department of Bioagricultural Sciences and Pest Management and Program in Plant Molecular Biology, Colorado State University, Fort Collins, CO, 80523-1177, USA
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Author for correspondence:

Jan E. Leach

Tel: +1 970 491 2924

Email: jan.leach@colostate.edu

Summary

  • Genomes of the rice (Oryza sativa) xylem and mesophyll pathogens Xanthomonas oryzae pv. oryzae (Xoo) and pv. oryzicola (Xoc) encode numerous secreted transcription factors called transcription activator-like (TAL) effectors. In a few studied rice varieties, some of these contribute to virulence by activating corresponding host susceptibility genes. Some activate disease resistance genes. The roles of X. oryzae TAL effectors in diverse rice backgrounds, however, are poorly understood.

  • Xoo TAL effectors that promote infection by activating SWEET sucrose transporter genes were expressed in TAL effector-deficient X. oryzae strain X11-5A, and assessed in 21 rice varieties. Some were also tested in Xoc on variety Nipponbare. Several Xoc TAL effectors were tested in X11-5A on four rice varieties.

  • Xoo TAL effectors enhanced X11-5A virulence on most varieties, but to varying extents depending on the effector and variety. SWEET genes were activated in all tested varieties, but increased virulence did not correlate with activation level. SWEET activators also enhanced Xoc virulence on Nipponbare. Xoc TAL effectors did not alter X11-5A virulence.

  • SWEET-targeting TAL effectors contribute broadly and non-tissue-specifically to virulence in rice, and their function is affected by host differences besides target sequences. Further, the utility of X11-5A for characterizing individual TAL effectors in rice was established.

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