Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China.
Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China.
Int J Mol Sci. 2024 Jan 24;25(3):1420. doi: 10.3390/ijms25031420.
The photoperiod is a major environmental factor in flowering control. Water spinach flowering under the inductive short-day condition decreases the yield of vegetative tissues and the eating quality. To obtain an insight into the molecular mechanism of the photoperiod-dependent regulation of the flowering time in water spinach, we performed transcriptome sequencing on water spinach under long- and short-day conditions with eight time points. Our results indicated that there were 6615 circadian-rhythm-related genes under the long-day condition and 8691 under the short-day condition. The three key circadian-rhythm genes, , , and , still maintained single copies and similar , , and feedback expression patterns, indicating the conservation of reverse feedback. In the photoperiod pathway, highly conserved genes were amplified into two copies ( and ) in water spinach. The significant difference in the expression of the two genes indicates functional diversity. Although the photoperiod core gene was duplicated to three copies in water spinach, only was highly expressed and strongly responsive to the photoperiod and circadian rhythms, and the almost complete inhibition of in water spinach may be the reason why water spinach does not bloom, no matter how long it lasts under the long-day condition. Differing from other species (, ) of the genus that have three members, water spinach lacks one of them, and the other two genes ( and ) encode only one CCT domain. In addition, through weighted correlation network analysis (WGCNA), some transcription factors closely related to the photoperiod pathway were obtained. This work provides valuable data for further in-depth analyses of the molecular regulation of the flowering time in water spinach and the genus.
光周期是控制开花的主要环境因素。水蕹菜在诱导短日照条件下开花会降低营养组织的产量和食用品质。为了深入了解水蕹菜光周期依赖性开花时间调控的分子机制，我们对长日照和短日照条件下的水蕹菜进行了 8 个时间点的转录组测序。结果表明，长日照条件下有 6615 个与昼夜节律相关的基因，短日照条件下有 8691 个。三个关键的昼夜节律基因、、和仍然保持单拷贝，并且相似的、、和反馈表达模式，表明反向反馈的保守性。在光周期途径中，高度保守的基因在水蕹菜中扩增为两个拷贝（和）。两个基因表达的显著差异表明其功能多样性。尽管水蕹菜的光周期核心基因被复制为三个拷贝，但只有表达量高，对光周期和昼夜节律反应强烈，而水蕹菜中几乎完全抑制可能是水蕹菜无论在长日照条件下持续多长时间都不开花的原因。与其他属（、）的三个成员不同，水蕹菜缺少一个成员，另外两个基因（和）只编码一个 CCT 结构域。此外，通过加权相关网络分析（WGCNA），获得了一些与光周期途径密切相关的转录因子。这项工作为进一步深入分析水蕹菜和属开花时间的分子调控提供了有价值的数据。
