Mol Plant Microbe Interact. 2014 Oct;27(10):1027-34. doi: 10.1094/MPMI-03-14-0065-R.
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.
植物通过各种类型的转录因子来转录调控防御相关基因，从而对病原体攻击做出反应。我们在水稻中鉴定到一个转录因子，OsNAC111，它属于 NAC 家族的 TERN 亚组，在稻瘟病菌（Magnaporthe oryzae）接种后转录上调。OsNAC111 定位于水稻细胞的细胞核中，在酵母和水稻细胞中具有转录激活活性。过表达 OsNAC111 的转基因水稻植株对稻瘟病菌表现出增强的抗性。在过表达 OsNAC111 的植株中，几种防御相关基因的表达，包括病程相关（PR）基因，与对照相比持续升高。这些基因在叶片中均表现出对稻瘟病的响应表达。其中，两个几丁质酶基因和一个β-1,3-葡聚糖酶基因在 OsNAC111 功能被嵌合阻遏物（OsNAC111-SRDX）抑制的转基因水稻植株中表达降低。OsNAC111 在水稻细胞中激活几丁质酶和β-1,3-葡聚糖酶基因启动子的转录。此外，在感染早期，OsNAC111-SRDX 植株中，感染部位的褐色色素沉着（水稻细胞对稻瘟病菌的防御反应）降低。这些结果表明，OsNAC111 正向调控一组特定的 PR 基因在疾病响应中的表达，并有助于抗病性。
