Page 108 - 《广西植物》2024年第12期
P. 108
2 2 6 6 广 西 植 物 44 卷
( 1. School of Ecol ̄Environmental Engineeringꎬ Qinghai Universityꎬ Xining 810016ꎬ Chinaꎻ 2. Key Laboratory of Landscape Plants of Qinghai
Provinceꎬ Xining 810016ꎬ Chinaꎻ 3. State Key Laboratory of Plateau Ecology and Agricultureꎬ Qinghai Universityꎬ Xining 810016ꎬ
Chinaꎻ 4. Academy of Animal Science and Veterinaryꎬ Qinghai Universityꎬ Xining 810016ꎬ China )
Abstract: The aerenchyma is an adaptive structure of Saussurea medusa in response to extreme environmentsꎬ and its
formation is usually accompanied by programmed cell death (PCD). The death of cells and the formation of aerenchyma
are typically regulated by the PAD4 gene ( Phytoalexin Deficient 4). Howeverꎬ the mechanism by which SmPAD4
regulates the formation of aerenchyma in S. medusa remains unclear. In this studyꎬ S. medusa was used as the
experimental materialꎬ and the gene SmPAD4 related to aerenchyma formation was cloned by homologous cloning and
RACE technologyꎬ and its sequenceꎬ phylogenetic evolutionꎬ expression and subcellular localization were analyzedꎬ and
its promoter was amplified by hi ̄TAIL PCR technology to explore its function in environmental adaptation. The results
were as follows:(1) The cDNA of SmPAD4 gene was successfully cloned with a total length of 2 047 bp(GenBank
accession number OR766038)ꎬ including an open reading frame of 1 866 bpꎬ encoding 621 amino acidsꎬ a molecular
formula of C H N O S . The protein was an alkaline and hydrophilic unstable protein. (2) Phylogenetic tree
3163 4906 848 910 26
analysis showed that SmPAD4 had high similarity with CcPAD4 of Cynara cardunculus. (3)A length of 1 049 bp promoter
sequence of SmPAD4 was amplifiedꎬ which included cis ̄acting elements such as light response elementꎬ hypoxia
response elementꎬ dry and auxin response elements.(4)Real ̄time quantitative fluorescence (qRT ̄PCR) analysis showed
that SmPAD4 gene was expressed in rootꎬ stem and leafꎬ and the expression level was the highest in leaf. Under
ultraviolet and hypoxia stressesꎬ the expression of SmPAD4 gene was up ̄regulated in leaf and stemꎬ and down ̄regulated
in root. ( 5) Subcellular localization showed that SmPAD4 was distributed in the nucleusꎬ cell membraneꎬ and
chloroplast. The results show that SmPAD4 gene has a unique protein domain and it responds to hypoxia and ultraviolet
environmental stressesꎬ so it plays an important role in the formation of aerenchyma and the response to adversity
stress. This study provides theoretical reference for further exploring the role of SmPAD4 gene in the environmental
adaptation process of Saussurea medusa.
Key words: Saussurea medusaꎬ SmPAD4ꎬ aerenchymaꎬ expression analysisꎬ hypoxia stressꎬ ultraviolet stress
水 母 雪 兔 子 ( Saussurea medusa ) 属 菊 科 et al.ꎬ 2021ꎻ支添添等ꎬ2022)ꎮ PAD4 响应各种非
(Asteraceae)风毛菊属( Saussurea)ꎬ为多年生草本 生物胁迫(如强光、紫外线辐射、干旱和寒冷等) 主
植物ꎬ主要分布于青藏高原地区(Pegadaraju et al.ꎬ 要通 过 次 级 信 使 介 导ꎬ 如 水 杨 酸 ( salicylic acidꎬ
2007ꎻDawa et al.ꎬ 2009ꎻ Szechynska ̄Hebda et al.ꎬ SA)、活性氧( reactive oxygen speciesꎬROS)、乙 烯
2016)ꎬ主要受高寒、低氧和强紫外辐射等极端环 (ethyleneꎬET)和其他信号分子等ꎬ并且在拟南芥
境的胁迫ꎮ 根、茎和叶中发达的通气组织是水母 与木本植物中被证明参与调节植物细胞程序性死
雪兔子最具有代表性的应对极端环境的结构特征 亡、细胞壁合成、种子产量、生物物质生成和水分
(王文和等ꎬ2007ꎻ蒋欣悦等ꎬ2023)ꎮ PAD4 基因在 利用(Feys et al.ꎬ 2001ꎻ Slesak et al.ꎬ 2014ꎻCui et
'
植物细胞程序性死亡和形成通气组织形成中起着 al.ꎬ 2017)ꎮ 已 有 大 量 研 究 表 明ꎬ PAD4 与 LSD1
重要作用(Bernacki et al.ꎬ 2019ꎬ 2023)ꎬ但目前水 ( Lesion Simulating Disease 1 ) 和 EDSI ( Enhanced
母雪兔子的非生物胁迫响应机制尚未明确ꎮ 因 Disease Susceptibility 1) 形成特定枢纽来调节植物
此ꎬ研 究 水 母 雪 兔 子 通 气 组 织 形 成 相 关 基 因 细胞死亡和适应生物和非生物胁迫( Aviv et al.ꎬ
SmPAD4ꎬ对揭示高山植物适应环境的特殊机制具 2002ꎻMateo et al.ꎬ 2004ꎻMühlenbock et al.ꎬ 2007ꎻ
有重要的理论意义ꎮ Gao et al.ꎬ 2010ꎻ Karpiński et al.ꎬ 2013ꎻ
PAD4 作为 R( resistance) 基因介导的信号转 Wituszyńska et al.ꎬ 2015)ꎮ 在 拟 南 芥 中ꎬ AtPAD4
导分子ꎬ是参与植物免疫应答、PCD 调控和通气组 突变导致 SA、ET 和 ROS 稳态受损ꎬ从而中断适应
织形成的关键基因ꎬ在植物响应生物与非生物胁 反应和 细 胞 死 亡 信 号 传 导ꎬ 并 且 在 低 氧 条 件 下
迫的过程中起到重要作用( Rietz et al.ꎬ 2011ꎻZeng AtPAD4 被 AtLSD1.1 负调控来参与乙烯途径的溶