Fan Jiangtao, Wang Yong, Dou Mengke, Hu Qiuhong, Li Qing, Gan Shengmei, Jing Mingwei, Wang Gang, Huang Xiong
Forest Ecology and Conservation in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chendu, 610000, China.
National Forestry and Grassland Southwest Engineering Technology Research Centre of Taxus, Sichuan Agricultural University, Chengdu, 610000, China.
BMC Genomics. 2025 Jul 31;26(1):705. doi: 10.1186/s12864-025-11916-z.
The NAC transcription factor family represents a large group of plant-specific genes involved in various biological processes, including secondary metabolite biosynthesis, responses to biotic and abiotic stresses, and hormone signaling. Taxus yunnanensis, a well-known medicinal plant, is the natural source of the anticancer diterpene paclitaxel. Despite the biological importance of NAC transcription factors, no comprehensive genome-wide study of the NAC gene family has been conducted in T. yunnanensis.
In this study, 44 NAC genes were identified from the T. yunnanensis genome. Gene structure analysis revealed that the number of exons ranged from 1 to 7, with most genes containing 2 to 3 exons. Chromosomal mapping showed an uneven distribution of TyuNACs across the 11 chromosomes. Duplication type analysis indicated that dispersed duplication is the primary mechanism driving the expansion of the TyuNACs, accounting for the largest proportion (24 genes), followed by tandem (12 genes) and proximal duplications (8 genes); no whole-genome or segmental duplication events were detected. Cis-regulatory element analysis suggested that TyuNACs are involved in key biological processes such as development, light response, stress adaptation, and hormone signaling. Expression profiling revealed diverse tissue-specific expression patterns, with most TyuNACs highly expressed in bark. Moreover, qRT-PCR analysis demonstrated that several TyuNACs respond to methyl jasmonate (MeJA) treatment. Yeast one-hybrid and related assays revealed that TyuNAC30 functions as a negative regulator of TyuDBTNBT, a key enzyme gene in the paclitaxel biosynthetic pathway.
This study presents the comprehensive genome-wide characterization of the NAC transcription factor family in T. yunnanensis. The findings underscore the predominant role of dispersed duplication in the expansion of the TyuNAC family, with additional contributions from tandem and proximal duplications. Importantly, TyuNAC30 was identified as a negative regulator of TyuDBTNBT, suggesting a key role in the transcriptional regulation of paclitaxel biosynthesis. These findings offer valuable insights for further exploration of the functional roles of NAC genes, particularly their involvement in the regulatory mechanisms underlying paclitaxel biosynthesis.
NAC转录因子家族是一大类植物特有的基因，参与多种生物学过程，包括次生代谢物生物合成、对生物和非生物胁迫的响应以及激素信号传导。云南红豆杉是一种著名的药用植物，是抗癌二萜紫杉醇的天然来源。尽管NAC转录因子具有生物学重要性，但尚未在云南红豆杉中对NAC基因家族进行全面的全基因组研究。
在本研究中，从云南红豆杉基因组中鉴定出44个NAC基因。基因结构分析表明，外显子数量从1到7不等，大多数基因含有2到3个外显子。染色体定位显示云南红豆杉NAC基因（TyuNACs）在11条染色体上分布不均。重复类型分析表明，分散重复是驱动TyuNACs扩增的主要机制，占比最大（24个基因），其次是串联重复（12个基因）和近端重复（8个基因）；未检测到全基因组或片段重复事件。顺式作用元件分析表明，TyuNACs参与发育、光响应、胁迫适应和激素信号传导等关键生物学过程。表达谱分析揭示了不同的组织特异性表达模式，大多数TyuNACs在树皮中高表达。此外，qRT-PCR分析表明，几个TyuNACs对茉莉酸甲酯（MeJA）处理有响应。酵母单杂交及相关试验表明，TyuNAC30作为紫杉醇生物合成途径中的关键酶基因TyuDBTNBT的负调控因子发挥作用。
本研究对云南红豆杉NAC转录因子家族进行了全面的全基因组特征分析。研究结果强调了分散重复在TyuNAC家族扩增中的主要作用，串联重复和近端重复也有额外贡献。重要的是，TyuNAC30被鉴定为TyuDBTNBT的负调控因子，表明其在紫杉醇生物合成转录调控中起关键作用。这些发现为进一步探索NAC基因的功能作用，特别是它们在紫杉醇生物合成调控机制中的作用提供了有价值的见解。
