Heading date is an important agronomic trait in rice (Oryza sativa L.). We previously fine-mapped two complementary genes, Late Heading Date 1 and Late Heading Date 2 (LH2), that control the late heading trait in rice. Here, we cloned and analyzed the function of LH2. LH2 was fine-mapped to a 53-kb genomic region. Sequencing analysis revealed that there were differences in the coding sequence of LOC_Os08g07740 between the varieties ‘Bo B’ and ‘Yuefeng B’. Therefore, LOC_Os08g07740 was identified as a candidate gene for LH2 and subsequently determined that LH2 is a Type 3 allele of Days To Heading 8. Transgenic plants of Yuefeng B carrying LH2 from Bo B significantly delayed the heading date under short-day and long-day conditions. A yeast two-hybrid analysis revealed that LH2 physically interacted with Heme Activator Protein (HAP) 5A, -H, -I, -L, -K, and HAP5-LIKE. The HAP5 domain of HAP5 family members has various functions. Further analysis revealed that LH2 represses photoperiodic flowering by controlling the expression of Early Heading Date 1, Heading date 3a, and Rice Flowering Locus T1 in rice.

中文翻译：

---

水稻晚抽穗控制基因LH2的克隆及功能分析

抽穗期是水稻（Oryza sativa L. ）的一个重要农艺性状。我们之前对两个互补基因进行了精细定位，即晚抽穗日期 1和晚抽穗日期 2 ( LH2 )，它们控制着水稻的晚抽穗性状。在这里，我们克隆并分析了LH2的功能。LH2被精细定位到一个 53-kb 的基因组区域。测序分析表明，'Bo B'和' Yuefeng B'两个品种的LOC_Os08g07740编码序列存在差异。因此，LOC_Os08g07740被鉴定为LH2的候选基因，随后确定LH2是Days To Heading 8 的3 型等位基因。携带Bo B LH2的月峰B转基因植株在短日照和长日照条件下显着延迟抽穗期。酵母双杂交分析显示 LH2 与血红素激活蛋白 (HAP) 5A、-H、-I、-L、-K 和 HAP5-LIKE 发生物理相互作用。HAP5 家族成员的 HAP5 域具有多种功能。进一步分析表明，LH2通过控制早抽穗期 1、抽穗期 3a和水稻开花位点 T1在水稻中的表达来抑制光周期开花。