【摘要】 沙棘(Hippophae rhamnoides L.)作为药食同源的重要植物,其果实在多个领域都有极高的利用价值。近年来,对经济树种的分枝进行改良是提高果实产量的一个重要途径。而TCP基因家族在调控生长发育及逆境响应中具有关键作用,其家族成员在植物分枝发育中有着重要作用。该研究通过生物信息学结合实验验证,系统鉴定了沙棘的TCP基因家族,并解析了其功能特性。该研究基于基因组数据筛选出29个沙棘TCP基因,并通过进化分析将其分为Class I(PCF亚族)和Class II(CYC/TB1亚族及CIN亚族)。研究发现, Class II亚族的TCP结构域碱性区比Class I亚族多4个保守氨基酸。染色体定位显示,沙棘TCP家族成员在染色体上分布不均,理化性质分析表明沙棘TCP家族多数蛋白呈亲水性且定位于细胞核。启动子分析发现了在沙棘TCP家族成员的启动子中,光响应、激素(如ABA)及胁迫相关顺式元件富集,暗示了沙棘TCP家族参与多重调控网络。共线性分析揭示了沙棘TCP基因与拟南芥、枣存在广泛进化保守性,且家族扩张主要由全基因组复制/片段复制驱动的跨染色体重复主导。组织特异性表达显示, CYC/TB1亚族基因Hr TCP12在刺和侧芽中高表达,在其余部位表达量较低,暗示其调控分枝发育的功能。亚细胞定位证实Hr TCP12和Hr TCP18主要定位于细胞核,符合转录因子特性。在84k杨中过表达Hr TCP12显著抑制杨树分生组织活性基因Pag WUS1/2的表达,初步验证了其通过抑制侧芽生长调控植物分枝的保守机制。该研究在全基因组范围内鉴定了沙棘TCP基因家族成员,并对CYC/TB1亚族基因进行了表达模式分析,发现了其成员具有明显的组织特异性表达特征,同时发现了Hr TCP12抑制杨树分生组织活性基因表达,为利用基因工程改良沙棘分枝特性提供了候选基因。更多还原

【Abstract】 Sea buckthorn(Hippophae rhamnoides L.), as an important plant of medicinal and food origin, its fruits are highly utilised in several fields. In recent years, the improvement of branching of economic tree species is an important way to increase its fruit yield. While the TCP gene family has a key role in regulating growth and development and response to adversity, its family members have important roles in plant meristem development. In this study, the TCP gene family in sea buckthorn was systematically identified and its functional properties were resolved through bioinformatics combined with experimental validation. In this study, 29 TCP genes were identified in sea buckthorn based on genomic data. Phylogenetic analysis classified them into Class I(PCF subfamily) and Class II(CYC/TB1 and CIN subfamilies). Notably, the TCP domain’s basic region in Class II contained four additional conserved amino acids compared to Class I. Chromosomal localisation showed that the family members were unevenly distributed on chromosomes, and physicochemical analyses showed that most of the proteins of the sea buckthorn TCP family were hydrophilic and localised in the nucleus. Promoter analysis revealed that the promoters of the family members were enriched in light-responsive, hormone(e.g., ABA) and stress-related cis-elements, suggesting their involvement in multiple regulatory networks. Covariance analysis revealed extensive evolutionary conservation of the sea buckthorn TCP genes with Arabidopsis thaliana and date, and the family expansion was dominated by trans-chromosomal duplications driven by whole-genome duplication/segmental duplication. Tissuespecific expression showed that the CYC/TB1 subfamily gene HrTCP12 was highly expressed in thorns and lateral shoots, with lower expression in the rest of the site, implying its function in regulating meristem development. Subcellular localisation confirmed that HrTCP12 and HrTCP18 were predominantly localised in the nucleus, consistent with transcription factor identity. Overexpression of HrTCP12 in 84k poplar significantly inhibited the expression of the active genes PagWUS1/2 in the meristematic tissue of poplar, which preliminarily verified its conserved mechanism of regulating plant meristems by inhibiting lateral shoot growth. In this study, TCP gene family in sea buckthorn was identified at a genome-wide scale and the expression patterns of the CYC/TB1 subfamily genes were analysed. It was found that their members exhibit obvious tissue-specific expression characteristics. Additionally, Hr TCP12 was found to inhibit the expression of active genes in the meristematic tissue of poplar, offering candidate genes for the improvement of meristematic characteristics in sea buckthorn using genetic approaches.更多还原