Long YuQing, Zeng Juan, Yang Min, Zhou XinRu, Zeng Mei, Liu ChangYu, Tong QiaoZhen, Zhou RiBao, Liu XiangDan
College of Pharmacy, Hunan University of Chinese Medicine, Changsha, 410208, China.
Key Laboratory of Germplasm Resources and Standardized Planting of Hunan Large-Scale Genuine Medicinal Materials, Changsha, 410208, China.
Genes Genomics. 2023 Apr;45(4):437-450. doi: 10.1007/s13258-022-01354-6. Epub 2023 Jan 25.
Lonicera macranthoides Hand.-Mazz. is an important medicinal plant. Xianglei-type (XL) L. macranthoides was formed after many years of cultivation by researchers on the basis of the natural mutant. The corolla of L. macranthoides XL remains unexpanded and its flowering period is nearly three times longer than that of wild-type (WT) plants. However, the molecular mechanism behind this desirable trait remains a mystery.
To understand the floral phenotype differences between L. macranthoides and L. macranthoides XL at the molecular level.
Transcriptome analysis was performed on L. macranthoides XL and WT. One DEG was cloned by RT-PCR amplification and selected for qRT-PCR analysis.
Transcriptome analysis showed that there were 5603 differentially expressed genes (DEGs) in XL vs. WT. Enrichment analysis of DEGs showed that pathways related to plant hormone signal transduction were significantly enriched. We identified 23 key genes in ethylene biosynthesis and signal transduction pathways. The most abundant were the ethylene biosynthesis DEGs. In addition, the open reading frames (ORFs) of WT and XL ETR2 were successfully cloned and named LM-ETR2 (GenBank: MW334978) and LM-XL-ETR2 (GenBank: MW334978), respectively. qRT-PCR at different flowering stages suggesting that ETR2 acts in the whole stage of flower development of WT and XL.
This study provides new insight into the molecular mechanism that regulates the development of special traits in the flowers of L. macranthoides XL. The plant hormone ethylene plays an important role in flower development and flowering duration prolongation in L. macranthoides. The ethylene synthesis gene could be more responsible for the flower phenotype of XL. The genes identified here can be used for breeding and improvement of other flowering plants after functional verification.
灰毡毛忍冬是一种重要的药用植物。湘蕾型灰毡毛忍冬是研究人员在自然突变体的基础上经过多年培育形成的。湘蕾型灰毡毛忍冬的花冠保持未展开状态，其花期比野生型植株长近三倍。然而，这一优良性状背后的分子机制仍是个谜。
在分子水平上了解灰毡毛忍冬与湘蕾型灰毡毛忍冬之间的花表型差异。
对湘蕾型灰毡毛忍冬和野生型灰毡毛忍冬进行转录组分析。通过RT-PCR扩增克隆一个差异表达基因（DEG）并进行qRT-PCR分析。
转录组分析表明，湘蕾型与野生型相比有5603个差异表达基因。差异表达基因的富集分析表明，与植物激素信号转导相关的途径显著富集。我们在乙烯生物合成和信号转导途径中鉴定出23个关键基因。乙烯生物合成差异表达基因最为丰富。此外，成功克隆了野生型和湘蕾型ETR2的开放阅读框（ORF），分别命名为LM-ETR2（GenBank：MW334978）和LM-XL-ETR2（GenBank：MW334978）。不同开花阶段的qRT-PCR表明，ETR2在野生型和湘蕾型花发育的整个阶段都起作用。
本研究为调控湘蕾型灰毡毛忍冬花特殊性状发育的分子机制提供了新的见解。植物激素乙烯在灰毡毛忍冬花发育和花期延长中起重要作用。乙烯合成基因可能对湘蕾型的花表型更有影响。这里鉴定出的基因经功能验证后可用于其他开花植物的育种和改良。
