Sakuraba Yasuhito, Piao Weilan, Lim Jung-Hyun, Han Su-Hyun, Kim Ye-Sol, An Gynheung, Paek Nam-Chon
Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea.
Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea Present address: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185, Republic of Korea.
Plant Cell Physiol. 2015 Dec;56(12):2325-39. doi: 10.1093/pcp/pcv144. Epub 2015 Oct 6.
NAM/ATAF1/ATAF2/CUC2 (NAC) is a plant-specific transcription factor (TF) family, and NACs participate in many diverse processes during the plant life cycle. Several Arabidopsis thaliana NACs have important roles in positively or negatively regulating leaf senescence, but in other plant species, including rice, the senescence-associated NACs (senNACs) remain largely unknown. Here we show that the rice senNAC TF ONAC106 negatively regulates leaf senescence. Leaves of onac106-1D (insertion of the 35S enhancer in the promoter region of the ONAC106 gene) mutants retained their green color under natural senescence and dark-induced senescence conditions. Genome-wide transcriptome analysis revealed that key senescence-associated genes (SGR, NYC1, OsNAC5, OsNAP, OsEIN3 and OsS3H) were differentially expressed in onac106-1D during dark-induced senescence. In addition to delayed senescence, onac106-1D also showed a salt stress-tolerant phenotype; key genes that down-regulate salt response signaling (OsNAC5, OsDREB2A, OsLEA3 and OsbZIP23) were rapidly up-regulated in onac106-1D under salt stress. Interestingly, onac106-1D also exhibited a wide tiller angle phenotype throughout development, and the tiller angle-related gene LPA1 was down-regulated in onac106-1D. Using yeast one-hybrid assays, we found that ONAC106 binds to the promoter regions of SGR, NYC1, OsNAC5 and LPA1. Taking these results together, we propose that ONAC106 functions in leaf senescence, salt stress tolerance and plant architecture by modulating the expression of its target genes that function in each signaling pathway.
NAM/ATAF1/ATAF2/CUC2（NAC）是植物特有的转录因子（TF）家族，NAC蛋白参与植物生命周期中的许多不同过程。拟南芥中的几个NAC蛋白在正向或负向调节叶片衰老中起重要作用，但在包括水稻在内的其他植物物种中，与衰老相关的NAC蛋白（senNACs）在很大程度上仍不清楚。在这里，我们表明水稻senNAC转录因子ONAC106负向调节叶片衰老。onac106 - 1D（在ONAC106基因启动子区域插入35S增强子）突变体的叶片在自然衰老和黑暗诱导衰老条件下保持绿色。全基因组转录组分析表明，在黑暗诱导衰老期间，关键的衰老相关基因（SGR、NYC1、OsNAC5、OsNAP、OsEIN3和OsS3H）在onac106 - 1D中差异表达。除了衰老延迟外，onac106 - 1D还表现出耐盐胁迫表型；在盐胁迫下，onac106 - 1D中下调盐反应信号的关键基因（OsNAC5、OsDREB2A、OsLEA3和OsbZIP23）迅速上调。有趣的是，onac106 - 1D在整个发育过程中还表现出宽分蘖角表型，并且分蘖角相关基因LPA1在onac106 - 1D中下调。通过酵母单杂交试验，我们发现ONAC106与SGR、NYC1、OsNAC5和LPA1的启动子区域结合。综合这些结果，我们提出ONAC106通过调节其在每个信号通路中起作用的靶基因的表达，在叶片衰老、耐盐胁迫和植物形态中发挥作用。
