Page 117 - 《广西植物》2026年第3期
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3 期 黄明慧等: 钩藤钩发育相关 SEPALLATA ̄like 基因的克隆与表达分析 4 9 3
( 1. College of Pharmacyꎬ Guizhou University of Traditional Chinese Medicineꎬ Guiyang 550025ꎬ Chinaꎻ 2. School of
Traditional Chinese Medicineꎬ Guangdong Pharmaceutical Universityꎬ Yunfu 527325ꎬ Guangdongꎬ China )
Abstract: The hook is a distinctive structure of the medicinal plant Uncaria rhynchophyllaꎬ and serves as its primary
medicinal part. Although the hook and inflorescence are considered to be homologous organsꎬ the developmental
mechanism of the hook remains unclear. To investigate the origin and the developmental mechanism of the hookꎬ this
study cloned the complete coding sequences of three SEPALLATA ( SEP) ̄like genesꎬ belonging to the MADS ̄box
transcription factor familyꎬ by using RT ̄PCR and RACE techniques. The functions of these SEP ̄like genes were
preliminarily characterized through bioinformatic predictionꎬ subcellular localizationꎬ transcriptional activation assaysꎬ
and RT ̄qPCR methods. The results were as follows: (1) The full ̄length cDNA of the three genesꎬ UrSEP1ꎬ UrSEP3.1
and UrSEP3.2ꎬ were 931ꎬ 981ꎬ 1 097 bp in lengthꎬ which contained the coding sequences (CDS) of 738ꎬ 726ꎬ 729 bpꎬ
encoding 245ꎬ 241ꎬ and 242 amino acid residuesꎬ respectively. All proteins contained conserved domainsꎬ including
MADS domainꎬ K ̄boxꎬ SEPⅠand SEPⅡmotifs. (2) Phylogenetic tree analysis revealed that UrSEPs exhibit the closest
relationship to CaSEPs from Coffea arabica. UrSEP1 clusters within the SEP1/ 2 clade of the LOFSEP subgroupꎬ while
UrSEP3.1 and UrSEP3.2 belong to the SEP3 subgroup. (3) Subcellular localization showed that UrSEPs were all
localized in the nucleus and confirmed the nuclear activity of UrSEPs. Transcriptional activation assays suggested that
UrSEP1 and UrSEP3. 2 might exhibit transcriptional activation activitiesꎬ indicating that they can bind DNA
directly. (4) Results of RT ̄qPCR revealed potential homology between hook and inflorescenceꎬ alongside developmental
divergence. UrSEP3.1 and UrSEP3.2 showed higher transcriptional levels in hook than in rootꎬ stem or leafꎬ with similar
expression patterns during hook and inflorescence developmentꎻ the expression level of UrSEP1 peaked in hook budꎬ
surpassing levels in other vegetative tissues and inflorescence budꎬ and displayed opposing expression patterns during
hook versus inflorescence development. In summaryꎬ the three UrSEPs genes encode nuclear ̄localized proteins from
SEP1/ 2 and SEP3 cladesꎬ implicating their roles in hook development and early ̄stage fate divergence between hook and
inflorescence. These results provide genetic insights into the origin of the hook and establish a foundation for elucidating
the molecular mechanisms underlying hook morphogenesis in Uncaria rhynchophylla.
Key words: Uncaria rhynchophyllaꎬ SEPALLATA ̄likeꎬ gene cloningꎬ subcellular localizationꎬ transcriptional activation
activityꎬ expression analysis
药用植物钩藤( Uncaria rhynchophylla) 为茜草 GRP2 和 EMS1ꎬ为其提供了初步的分子证据ꎮ 目
科钩藤属藤本植物ꎬ其药用部位为带钩茎枝ꎬ作为 前ꎬ关于钩藤钩器官的形态发生尚未有详细的基因
著名中药材和民族药材之一用于治疗高血压和神 层面研究报道ꎬ对于钩发育相关基因的分析能为阐
经系统疾病(邓宽平等ꎬ2021ꎻ涂冬萍等ꎬ2021ꎻ段建 明钩器官的来源提供进一步线索ꎮ
平等ꎬ2024)ꎬ其中包含以钩藤碱和异钩藤碱为主的 SEPALLATA(SEP)基因编码一类植物特有的
单萜吲哚类生物碱及三萜类化合物等活性成分ꎬ研 MIKC 型 MADS ̄box 转录因子ꎬ除 MADS 结构域以
究发现其具有保护神经细胞、调节神经递质、抑制 外ꎬ还包含 I、K 及 C 末端结构域ꎬ能够发挥“桥梁”
铁死亡等作用(Qin et al.ꎬ 2021ꎻ Liu et al.ꎬ 2024)ꎮ 的作用参与蛋白互作网络ꎬ与同为 MADS ̄box 转录
钩藤的钩器官作为库ꎬ能够接收并储存叶中合成的 因子的蛋白形成多种复合物ꎬ并直接结合下游基
生物碱(阙云飞等ꎬ2023)ꎮ 邓宽平等(2021)通过对 因 启 动 子 CArG ̄box 序 列 上 调 控 制 其 转 录
钩器官进行解剖学研究ꎬ提出其为茎侧枝变态发育 (Hugouvieux & Zubietaꎬ 2018)ꎮ SEP 是被子植物
而来ꎬ但与茎相比其结构更为简单ꎬ仅具有初生结 花发育经典 ABCDE 模型中的 E ̄class 基因ꎬ被分为
构ꎮ 长期以来的形态学研究认为钩藤的钩和花序 SEP3 ( AGL9 ) 和 LOFSEP 2 个 亚 家 族ꎬ 其 中
是同源器官 ( Sperotto et al.ꎬ 2020)ꎬ 并且 Wan 等 LOFSEP 又 被 分 为 SEP1 / 2、 FBP9 / 23 和 SEP4 3
(2023)在对单钩生长模式的转录组学研究中发现 个分支(Dreni & Ferrándizꎬ 2022)ꎮ 模式植物拟南
了 4 个花器官发育相关的基因ꎬ即 AGAMOUS、SRS、 芥( Arabidopsis thaliana) 中共有 4 个 SEP 基因ꎬ分

