黄瓜CAD家族基因介导木质素沉积调控叶柄夹角建成

doi:10.13560/j.cnki.biotech.bull.1985.2026-0106

摘要/Abstract

摘要：

目的明确黄瓜（Cucumis sativus L.）CAD基因家族的组成特征及其在叶柄夹角形成中的潜在作用，为解析株型建成机制提供候选基因资源。方法基于黄瓜参考基因组CLv4.0，利用结构域检索与同源比对方法鉴定CAD基因家族成员，并对其染色体定位、蛋白理化性质、基因结构、保守基序、系统进化关系、启动子顺式作用元件及共线性关系进行系统分析；结合多组织转录组数据筛选候选基因，在不同叶柄夹角材料中通过RT-qPCR分析其在近轴叶柄基部与生长点叶片中的表达模式，并测定木质素含量及进行亚细胞定位验证。结果在黄瓜基因组中共鉴定到22个CAD基因，分布于7条染色体上，并检测到3对串联重复基因。系统进化分析将其划分为4个亚类，其中第Ⅱ亚类成员数量最多，表现出明显扩张趋势。启动子分析显示，CsCAD基因富含激素响应及非生物胁迫相关顺式作用元件。多组织表达分析表明，部分CsCAD基因在机械支撑相关组织中高表达。进一步分析发现，在小叶柄夹角材料中，CsCAD13等基因在近轴叶柄基部显著高表达；而在大叶柄夹角材料中，CsCAD19、CsCAD14等基因在生长点叶片中高表达。木质素含量测定结果表明，小夹角材料在近轴叶柄基部的木质素积累显著高于大夹角材料。亚细胞定位结果显示，不同CsCAD蛋白在细胞内定位存在差异。结论黄瓜CAD基因家族在进化过程中既保持保守性，又发生扩张与功能分化。部分CsCAD基因通过调控近轴叶柄基部木质素积累或顶端组织发育，参与叶柄夹角形成，可作为黄瓜株型改良的潜在候选基因。本研究首次将CAD基因家族与黄瓜叶柄夹角这一株型关键性状建立联系。

关键词: 黄瓜, 叶柄夹角, CAD基因家族, 近轴叶柄基部, 木质素生物合成, 组织特异性表达, 株型建成, 全基因组鉴定

Abstract:

Objective To characterize the CAD gene family in cucumber (Cucumis sativus L.) and explore its potential roles in regulating petiole angle formation, providing candidate genes for improving plant architecture. Method Based on the cucumber reference genome CLv4.0, CAD family members were identified using domain-based and homology-based approaches. Their chromosomal distribution, physicochemical properties, gene structures, conserved motifs, phylogenetic relationships, promoter cis-acting elements, and synteny were systematically analyzed. Candidate genes were further screened using multi-tissue transcriptome data. Expression patterns were analyzed by RT-qPCR in the adaxial petiole base and shoot-tip leaves of cucumber materials with contrasting petiole angles. Lignin content was measured, and subcellular localization of selected proteins was determined. Result A total of 22 CAD genes were identified in the cucumber genome and unevenly distributed across seven chromosomes, with three pairs of tandem duplications detected. Phylogenetic analysis classified these genes into four subgroups, among which subgroup II showed significant expansion. Promoter analysis revealed that CsCAD genes were enriched in hormone-responsive and stress-related cis-elements. Tissue expression analysis indicated that several CsCAD genes were highly expressed in mechanically relevant tissues. Further analysis showed that CsCAD13 and related genes were highly expressed in the adaxial petiole base of small-angle materials, whereas CsCAD19 and CsCAD14 exhibited higher expression in shoot-tip leaves of large-angle materials. Lignin content was significantly higher in the adaxial petiole base of small-angle materials. Subcellular localization revealed distinct intracellular distribution patterns among CsCAD proteins. Conclusion The cucumber CAD gene family exhibits both conservation and expansion with functional divergence. Some CsCAD genes may regulate petiole angle formation by modulating lignin accumulation in the adaxial petiole base or affecting shoot-tip tissue development, providing potential targets for cucumber plant architecture improvement. This study is the first to link the CAD gene family with petiole angle, a key trait of plant architecture in cucumber.

Key words: Cucumissativus L., petiole angle, CAD gene family, adaxial petiole base, lignin biosynthesis, tissue-specific expression, plant architecture, genome-wide identification

秦少敏, 苗晗, 董邵云, 官健涛, 顾兴芳, 李森, 刘小萍, 张圣平. 黄瓜CAD家族基因介导木质素沉积调控叶柄夹角建成[J]. 生物技术通报, 2026, 42(9): 137-146.

QIN Shao-min, MIAO Han, DONG Shao-yun, GUAN Jian-tao, GU Xing-fang, LI Sen, LIU Xiao-ping, ZHANG Sheng-ping. CsCAD Genes Mediate Lignin Deposition to Regulate Petiole Angle Formation in Cucumber[J]. Biotechnology Bulletin, 2026, 42(9): 137-146.

图/表 10

表1 不同黄瓜材料15-17节位叶柄夹角测定

Table 1 Petiole angle measurements at nodes 15-17 in different cucumber materials

材料 Material	节位15 Node15 （°）	节位16 Node16 （°）	节位17 Node17 （°）	平均值 Mean （°）
R369	25.67 ± 0.67	26.00 ± 0.58	26.33 ± 0.67	26.00 ± 0.33
R506	43.67 ± 1.76	44.33 ± 0.88	43.67 ± 1.76	43.89 ± 0.67
R116	63.00 ± 3.46	61.33 ± 0.88	61.67 ± 3.33	62.00 ± 1.04
R60	55.00 ± 1.73	55.33 ± 2.03	54.67 ± 0.33	55.00 ± 0.33

图1 植物样本采集位置分布图

Fig. 1 Distribution diagram of plant sample collection sites

表2 不同叶柄夹角黄瓜材料近轴叶柄基部和生长点叶片的木质素含量比较

Table 2 Comparison of lignin content in adaxial petiole base and shoot-tip leaves among cucumber materials with different petiole angles

材料 Sample	取样部位 Sampling part	木质素含量 Lignin content （mg/g）	百分含量 Percentage （%）
R116	近轴叶柄基部	91.87 ± 0.50	9.19 ± 0.04
	生长点叶片	44.41 ± 4.17	4.44 ± 0.37
R60	近轴叶柄基部	96.10 ± 1.51	9.61 ± 0.15
	生长点叶片	73.53 ± 1.32	7.35 ± 0.13
R369	近轴叶柄基部	145.89 ± 1.31	14.59 ± 0.13
	生长点叶片	103.23 ± 0.87	10.32 ± 0.09
R506	近轴叶柄基部	140.36 ± 1.53	14.04 ± 0.15
	生长点叶片	67.70 ± 0.44	6.77 ± 0.04

图2 黄瓜CsCAD家族基因的染色体定位

Fig. 2 Chromosomal distribution of the CsCAD gene family in cucumber

图3 CsCAD基因结构分析A：系统发育树与保守基序；B：保守结构域；C：基因结构；D：顺式作用元件

Fig. 3 Gene structure analysis of CsCADA: Phylogenetic tree and conserved motifs. B: Conserved domains. C: Gene structures. D: Cis-acting elements

图4 CAD基因家族系统进化分析

Fig. 4 Phylogenetic analysis of the CAD gene family

图5 黄瓜与拟南芥、甜瓜的CsCAD基因共线性分析

Fig. 5 Collinearity analysis of CsCAD genes among cucumber, Arabidopsis thaliana, and Cucumis melo

图6 黄瓜CsCAD基因在不同组织中的表达谱分析

Fig. 6 Expression profiles of CsCAD genes across different tissues in cucumber

图7 候选CsCAD基因在不同叶柄夹角材料近轴叶柄基部和生长点叶片中的表达分析柱状图上方的横线和符号表示组间差异的显著性；ns表示差异不显著（P>0.05）；星号表示差异显著：* P<0.05，** P<0.01，*** P<0.001，**** P<0.000 1

Fig. 7 Expression analysis of candidate CsCAD genes in adaxial petiole base and shoot-tip leaves of cucumber materials with different petiole anglesHorizontal lines and symbols above the bars indicate the significance of differences between groups. ns indicates no significant difference (P>0.05); asterisks indicate significant differences: * P<0.05, ** P<0.01, *** P<0.001, and **** P<0.000 1

图8 CsCAD13、CsCAD14和CsCAD19的亚细胞定位

Fig. 8 Subcellular localization of CsCAD13, CsCAD14 and CsCAD19 proteins

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