State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China.
The State Key Laboratory of Subtropical Silviculture, College of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou, 311300, China.
Plant Physiol Biochem. 2022 Nov 1;190:35-46. doi: 10.1016/j.plaphy.2022.08.030. Epub 2022 Sep 6.
Though many biological roles of ethylene have been investigated intensively, the molecular mechanism of ethylene's action in woody plants remains unclear. In this study, we investigated the effects of exogenous 1-aminocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene, on the growth of Neolamarckia cadamba seedlings, a fast-growing tropical tree. After 14 days of ACC treatment, the plants showed a reduced physiological morphology while stem diameter increased; however, this did not occur after the addition of 1-MCP. Meanwhile, the lignin content of N. cadamba also increased. Transcriptome analysis revealed that the expression of the ethylene biosynthesis and signaling genes ACC oxidase (ACO) and ethylene insensitive 3 (EIN3) were up-regulated mainly at the 6th hour and the 3rd day of the ACC treatment, respectively. The transcription levels of transcription factors, mainly in the basic helix-loop-helix (bHLH), ethylene response factor (ERF), WRKY and v-myb avian myeloblastosis viral oncogene homolog (MYB) families, involved in the ethylene signaling and secondary growth also increased significantly. Furthermore, in accordance to the increased lignification of the stem, the transcriptional level of key enzymes in the phenylalanine pathway were elevated after the ACC treatment. Our results revealed the physiological and molecular mechanisms underlying the secondary growth stimulated by exogenous ACC treatment on N. cadamba seedlings.
尽管乙烯的许多生物学功能已经得到了深入研究，但乙烯在木本植物中的作用机制仍不清楚。在本研究中，我们研究了外源 1-氨基环丙烷-1-羧酸（ACC），即乙烯前体，对速生热带树种泡桐幼苗生长的影响。在 ACC 处理 14 天后，植物表现出生理形态减小，而茎直径增加；然而，添加 1-MCP 后则不会发生这种情况。同时，泡桐的木质素含量也增加了。转录组分析表明，乙烯生物合成和信号转导基因 ACC 氧化酶（ACO）和乙烯不敏感 3（EIN3）的表达主要在 ACC 处理的第 6 小时和第 3 天被上调。涉及乙烯信号转导和次生生长的转录因子的转录水平，主要在碱性螺旋-环-螺旋（bHLH）、乙烯反应因子（ERF）、WRKY 和 v-myb 禽成髓细胞瘤病毒致癌基因同源物（MYB）家族中，也显著增加。此外，根据茎木质化程度的增加，ACC 处理后苯丙氨酸途径中的关键酶的转录水平升高。我们的研究结果揭示了外源 ACC 处理刺激泡桐幼苗次生生长的生理和分子机制。
