Eiichi Minami,1 and
1GMO Research Center, and 2Division of Plant Sciences, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan; 3Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Higashi 1-1-1, Tsukuba, Ibaraki 305-8562, Japan; 4Institute for Environmental Research and Technology (IEST), Saitama University, Saitama 338-8570 Japan; 5Sakata Seed Corporation, Kimitsu Research Station, 358 Uchikoshi, Sodegaura, Chiba 299-0217, Japan
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Accepted 10 June 2014.
Plants respond to pathogen attack by transcriptionally regulating defense-related genes via various types of transcription factors. We identified a transcription factor in rice, OsNAC111, belonging to the TERN subgroup of the NAC family that was transcriptionally upregulated after rice blast fungus (Magnaporthe oryzae) inoculation. OsNAC111 was localized in the nucleus of rice cells and had transcriptional activation activity in yeast and rice cells. Transgenic rice plants overexpressing OsNAC111 showed increased resistance to the rice blast fungus. In OsNAC111-overexpressing plants, the expression of several defense-related genes, including pathogenesis-related (PR) genes, was constitutively high compared with the control. These genes all showed blast disease-responsive expression in leaves. Among them, two chitinase genes and one β-1,3-glucanase gene showed reduced expression in transgenic rice plants in which OsNAC111 function was suppressed by a chimeric repressor (OsNAC111-SRDX). OsNAC111 activated transcription from the promoters of the chitinase and β-1,3-glucanase genes in rice cells. In addition, brown pigmentation at the infection sites, a defense response of rice cells to the blast fungus, was lowered in OsNAC111-SRDX plants at the early infection stage. These results indicate that OsNAC111 positively regulates the expression of a specific set of PR genes in the disease response and contributes to disease resistance.
© 2014 The American Phytopathological Society