Uji Yuya, Akimitsu Kazuya, Gomi Kenji
Plant Genome and Resource Research Center, Faculty of Agriculture, Kagawa University, Miki, Kagawa, 761-0795, Japan.
Planta. 2017 Jun;245(6):1241-1246. doi: 10.1007/s00425-017-2697-5. Epub 2017 Apr 19.
The jasmonic acid (JA)-responsive transcription factor OsMYC2 acts as a positive regulator of leaf senescence by direct regulation of some senescence-associated genes in rice. OsMYC2, a transcription factor (TF), acts as a positive regulator of jasmonic acid (JA) signaling involved in development and defense in rice. Here, we report that OsMYC2 plays an important role in leaf senescence under dark-induced senescence (DIS) conditions. Overexpression of OsMYC2 significantly promoted leaf senescence, indicated by reduction of chlorophyll content under DIS conditions in rice. Leaf senescence under the DIS conditions was negatively regulated by OsJAZ8, a rice jasmonate ZIM-domain protein involved in the JA signaling pathway. OsMYC2 upregulated the expression of some senescence-associated genes (SAGs) and selectively bound to the G-box/G-box-like motifs in the promoters of some SAGs in vivo. These results suggest that OsMYC2 acts as a positive regulator of leaf senescence by direct- or indirect-regulation of SAGs in rice.
茉莉酸（JA）响应转录因子OsMYC2通过直接调控水稻中的一些衰老相关基因，作为叶片衰老的正调控因子发挥作用。OsMYC2是一种转录因子（TF），作为参与水稻发育和防御的茉莉酸（JA）信号传导的正调控因子发挥作用。在此，我们报道OsMYC2在黑暗诱导衰老（DIS）条件下的叶片衰老中起重要作用。OsMYC2的过表达显著促进了叶片衰老，这在水稻DIS条件下叶绿素含量的降低中得到体现。在DIS条件下的叶片衰老受到OsJAZ8的负调控，OsJAZ8是一种参与JA信号通路的水稻茉莉酸ZIM结构域蛋白。OsMYC2上调了一些衰老相关基因（SAGs）的表达，并在体内选择性地结合到一些SAGs启动子中的G-box/G-box样基序上。这些结果表明，OsMYC2通过直接或间接调控水稻中的SAGs，作为叶片衰老的正调控因子发挥作用。
