State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, PR China.
Department of Biology Centre for Forest Biology, University of Victoria, Victoria, BC, 11, Canada.
BMC Genomics. 2020 Jul 22;21(1):508. doi: 10.1186/s12864-020-06918-y.
Floral transition plays an important role in development, and proper time is necessary to improve the value of valuable ornamental trees. The molecular mechanisms of floral transition remain unknown in perennial woody plants. "Bairihua" is a type of C. bungei that can undergo floral transition in the first planting year.
Here, we combined short-read next-generation sequencing (NGS) and single-molecule real-time (SMRT) sequencing to provide a more complete view of transcriptome regulation during floral transition in C. bungei. The circadian rhythm-plant pathway may be the critical pathway during floral transition in early flowering (EF) C. bungei, according to horizontal and vertical analysis in EF and normal flowering (NF) C. bungei. SBP and MIKC-MADS-box were seemingly involved in EF during floral transition. A total of 61 hub genes were associated with floral transition in the MEturquoise model with Weighted Gene Co-expression Network Analysis (WGCNA). The results reveal that ten hub genes had a close connection with the GASA homologue gene (Cbu.gene.18280), and the ten co-expressed genes belong to five flowering-related pathways. Furthermore, our study provides new insights into the complexity and regulation of alternative splicing (AS). The ratio or number of isoforms of some floral transition-related genes is different in different periods or in different sub-genomes.
Our results will be a useful reference for the study of floral transition in other perennial woody plants. Further molecular investigations are needed to verify our sequencing data.
花发育在植物的生长和繁殖中起着重要的作用，因此，了解花发育的分子机制对于理解植物的生长发育和适应环境具有重要意义。然而，在多年生木本植物中，花发育的分子机制仍然知之甚少。“百日红”是紫薇的一种，在第一年种植时可以经历花发育的转变。
在这里，我们结合短读长二代测序（NGS）和单分子实时（SMRT）测序，提供了紫薇花发育过程中转录组调控的更完整视图。根据早花（EF）和正常花（NF）紫薇的水平和垂直分析，生物钟-植物途径可能是 EF 紫薇花发育的关键途径。SBP 和 MIKC-MADS 框似乎参与了 EF 期间的花发育。通过加权基因共表达网络分析（WGCNA），MEturquoise 模型共鉴定出 61 个与花发育相关的枢纽基因。结果表明，十个枢纽基因与 GASA 同源基因（Cbu.gene.18280）密切相关，这十个共表达基因属于五个与开花相关的途径。此外，我们的研究为替代剪接（AS）的复杂性和调控提供了新的见解。一些花发育相关基因的异构体的比例或数量在不同时期或不同亚基因组中是不同的。
我们的研究结果将为其他多年生木本植物的花发育研究提供有用的参考。需要进一步的分子研究来验证我们的测序数据。
