Zhu Shanshan, Wang Jiachang, Cai Maohong, Zhang Huan, Wu Fuqing, Xu Yang, Li Chaonan, Cheng Zhijun, Zhang Xin, Guo Xiuping, Sheng Peike, Wu Mingming, Wang Jiulin, Lei Cailin, Wang Jie, Zhao Zhichao, Wu Chuanyin, Wang Haiyang, Wan Jianmin
National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, PR China.
National Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, PR China.
J Exp Bot. 2017 Jan 1;68(3):553-568. doi: 10.1093/jxb/erw468.
Heading date is an important agronomic trait related to crop yield. Many genes related to heading date have already been identified in rice (Oryza sativa), and a complicated, preliminary regulatory genetic network has also already been established, but the protein regulatory network is poorly understood. We have identified a novel heading date regulator, Heme Activator Protein like 1 (OsHAPL1), which inhibits flowering under long-day conditions. OsHAPL1 is a nuclear-localized protein that is highly expressed in leaves in a rhythmic manner. OsHAPL1 can physically interact with Days To Heading on chromosome 8 (DTH8), which physically interacts with Heading date 1 (Hd1) both in vitro and in vivo. OsHAPL1 forms a complex with DTH8 and Hd1 in Escherichia coli. OsHAPL1, DTH8, and Hd1 physically interact with the HAP complex, and also with general transcription factors in yeast (Saccharomyces cerevisiae). Further studies showed that OsHAPL1 represses the expression of the florigen genes and FLOWERING LOCUS T 1 (RFT1) and Hd3a through Early heading date 1 (Ehd1). We propose that OsHAPL1 functions as a transcriptional regulator and, together with DTH8, Hd1, the HAP complex, and general transcription factors, regulates the expression of target genes and then affects heading date by influencing the expression of Hd3a and RFT1 through Ehd1.
抽穗期是与作物产量相关的重要农艺性状。在水稻（Oryza sativa）中已经鉴定出许多与抽穗期相关的基因，并且已经建立了一个复杂的初步调控遗传网络，但对蛋白质调控网络的了解却很少。我们鉴定出一种新的抽穗期调节因子，即类血红素激活蛋白1（OsHAPL1），它在长日照条件下抑制开花。OsHAPL1是一种定位于细胞核的蛋白质，在叶片中以节律性方式高度表达。OsHAPL1能与8号染色体上的抽穗天数（DTH8）发生物理相互作用，而DTH8在体外和体内均能与抽穗期1（Hd1）发生物理相互作用。OsHAPL1在大肠杆菌中与DTH8和Hd1形成复合物。OsHAPL1、DTH8和Hd1能与HAP复合物以及酵母（Saccharomyces cerevisiae）中的一般转录因子发生物理相互作用。进一步研究表明，OsHAPL1通过早熟抽穗期1（Ehd1）抑制成花素基因及抽穗开花位点T 1（RFT1）和Hd3a的表达。我们提出，OsHAPL1作为一种转录调节因子，与DTH8、Hd1、HAP复合物以及一般转录因子一起，调节靶基因的表达，然后通过Ehd1影响Hd3a和RFT1的表达来影响抽穗期。
