Elicitor-induced down-regulation of cell cycle-related genes in tobacco cells

Authors

  • KAORU SUZUKI,

    Corresponding author
    1. Molecular and Cellular Breeding Research Group, Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1–1 Higashi, Tsukuba, Ibaraki 305–8566, Japan
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  • TAKUMI NISHIUCHI,

    1. Molecular and Cellular Breeding Research Group, Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1–1 Higashi, Tsukuba, Ibaraki 305–8566, Japan
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    • *

      Present address: Division of Functional Genomics, Advanced Science Research Center, Kanazawa University, 13–1 Takaramachi, Kanazawa 920–0934, Japan.

  • YUKO NAKAYAMA,

    1. Molecular and Cellular Breeding Research Group, Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1–1 Higashi, Tsukuba, Ibaraki 305–8566, Japan
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  • MASAKI ITO,

    1. Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464–8601, Japan
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  • HIDEAKI SHINSHI

    1. Molecular and Cellular Breeding Research Group, Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1–1 Higashi, Tsukuba, Ibaraki 305–8566, Japan
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Kaoru Suzuki. Fax: + 81 29 861 6090; e-mail: kaoru-suzuki@aist.go.jp

ABSTRACT

The fungal elicitors, a xylanase from Trichoderma viride and an extract from the cell wall of Phytophthora infestans, are shown to cause a rapid reduction of the mRNA levels of various cell cycle-related genes, including MAP kinase genes and cyclin genes, in cultured tobacco cells (Nicotiana tabacum cv. Xanthi, line XD6S). Pharmacological analyses suggest that the elicitor-induced decrease in B1-type cyclin (Nicta;CycB1;3) and A1-type cyclin (Nicta;CycA1;1) mRNAs may be due to transcriptional repression, and that in D3-type cyclin (Nicta;CycD3;2) mRNA due to destabilization of the mRNA molecule itself. The activity of protein kinases is required for both the activation of defence genes and the repression of cyclin genes. The transcriptional activity of the promoter of the B1-class cyclin gene decreases upon elicitor treatment. The transactivation activity of NtmybA2, a tobacco Myb transcription activator for the M phase-specific cis-acting elements in the promoter of the B-type cyclin gene, is inhibited by elicitor treatment. In addition, the mRNA levels of NtmybA2 and two other related genes, NtmybA1 and NtmybB, decrease in response to the elicitor. Finally, we discuss a negative cross-talk between signal transduction pathways for growth and defence responses, which might be important for adaptation to environmental stress by potential pathogens.

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