Page 154 - 《广西植物》2023年第2期
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3 4 8                                  广  西  植  物                                         43 卷
                 survive drought stressꎬ with a strong recovery ability under drought stress. To investigate the molecular mechanisms and
                 expression characteristics of the SpLEA1 gene in drought ̄tolerant plantsꎬ we used the highly drought ̄tolerant plant
                 S. pulvinata as experimental material and obtained the cDNA sequence of the SpLEA1 gene by RT ̄PCR based on the
                 transcriptome sequencing results. The promoter sequence was obtained by the HiTail ̄PCR techniqueꎬ and the sequence
                 was analyzed by bioinformatics. qRT ̄PCR was used to analyze the expression pattern of the SpLEA1 gene under drought
                 stress. The results were as follows: (1) The length of SpLEA1 was 476 bpꎬ the open reading frame (ORF) was 279 bpꎬ
                 and it encoded 92 amino acids. The predicted molecular weight of the protein was 9 491.46 Daꎬ and the isoelectric point
                 was 5.45. The predicted protein structure analysis showed that the protein was hydrophilic. The protein contained ten
                 phosphorylation sitesꎬ of which six serinesꎬ three tyrosinesꎬ and one threonineꎬ respectivelyꎬ and the predicted
                 secondary structures showed that the protein was mainly composed of α ̄helix and random coil. (2) The conserved
                 structural domain of the SpLEA1 protein was predicted to be Lea ̄5ꎬ derived from the LEA1 family. Based on the
                 phylogenetic tree and genetic distanced matrixꎬ the SpLEA1 was found to have high homology with Lea ̄5 protein from
                 Cicer arietinum and Trifolium pratense. (3) Predictive analysis of cis ̄acting elements in promoter sequenced revealed that
                 the SpLEA1 gene promoter contained five classes of hormone response elements and functional elements related to the
                 drought stress response. The SpLEA1 gene was hypothesized to have multiple functions in the plant body and was closely
                 related to drought stress response mechanisms. (4) SpLEA1 gene expression was up ̄regulated under natural dehydration
                 treatment and peaked in 12 h. After rehydration treatment for 24 hꎬ expression was significantly down ̄regulated. In
                 summaryꎬ the SpLEA1 gene is likely to be involved in the regulation of drought stress response mechanisms in matted
                 curly cypress. This results provide the reference for further studies on the function of the matted cypress SpLEA1 gene
                 under drought stress and its expression regulation mechanism.
                 Key words: Selaginella pulvinataꎬ SpLEA1ꎬ genetic cloningꎬ promoter cloningꎬ expression analysis



                植物在长期进化过程中ꎬ对外界的生物胁迫                            泛分布ꎬ典型代表为棉花 D ̄19、小麦 EM 蛋白、大
            与非生物胁迫有系统的生理及分子响应机理ꎮ 研                             麦 B19 蛋白等ꎮ LEA1 家族成员均具亲水性ꎬ各成

            究报 道 指 出ꎬ 胚 胎 发 育 晚 期 丰 富 蛋 白 ( late               员之间具有亲水性极高的 20 个氨基酸保守基序
            embryogenesis abundantꎬLEA) 与植物抗逆性相关ꎬ              ( GGETRKEQLGEEGYREMGRK )ꎬ 其 数 量 多 变
            广泛参与植物对非生物胁迫的响应过程( 李翔ꎬ                             (Stacy et al.ꎬ 1995)ꎮ
            2016)ꎮ LEA 蛋白最初是在棉花种子中分离克隆                             在植物中克隆目的基因的启动子能进一步系
            得到的(Dure et al.ꎬ 1981)ꎬ之后研究发现 LEA 蛋                统分析基因的功能ꎮ 植物启动子是一段含有转录

            白广泛存在于植物、无脊椎动物及原核生物中ꎮ                              起始位点ꎬ调控基因表达的 DNA 序列ꎬ启动子的
            LEA 基因在植物的整个发育阶段均有表达ꎬ特别                            转录频率、起始方向和位点均是基因转录调控表
            是在植物遭受如干旱ꎬ高温等环境胁迫时ꎬLEA 基                           达的关键( Liu et al.ꎬ 1997ꎻ王志新等ꎬ2011ꎻ张曦

            因在植物组织细胞中大量表达ꎬ积累丰富的 LEA                            予等ꎬ2019)ꎮ 启动子主要包含一些特异性的调控
            蛋白以应对外界环境( Wiseꎬ 2003ꎻSilveira et al.ꎬ             基序(梅玉芹ꎬ2018)ꎬ在结构和功能上可以分为组
            2008)ꎮ Hunault 和 Jaspard(2010) 建立了 LEA 蛋           成型启动子、诱导型启动子和组织特异型启动子
            白数 据 库 ( Late Embryogenesis Abundant Proteins      (杨瑞娟等ꎬ2018)ꎮ 研究表明ꎬ诱导型启动子在外
            databaseꎬLEAPdb)ꎬ根据 LEA 蛋白氨基酸序列的 8                 界环境因素发生改变时ꎬ会使基因瞬时或持续性
            个保守的 PFAM 结构域对 LEA 蛋白成员进行生物                        上调表达( Durzo et al.ꎬ 2013)ꎮ Zheng 等(2019)
            信息学分析ꎮ 通过 LEA 蛋白数据库确认研究中所                          从卷 心 菜 中 分 离 得 到 了 一 个 非 典 型 LEA 基 因
            提取的 LEA 蛋白的 PFAM 号ꎬ可以确定其所属的                        LpLEA 基因及其启动子序列ꎬ分析表明中 LpLEA 基
            LEA 蛋白家族ꎬ为后续实验提供理论依据ꎮ LEA1                         因的启动子中存在与非生物胁迫有关的独特顺式
            (group 1 late ̄embryogenesis ̄abundant proteins) 是以  作用调控元件ꎬLpLEA 基因在不同非生物胁迫及脱
            无规则结构形式存在的亲水性蛋白ꎬ在植物中广                              落酸诱导下在不同部位表达量均提高ꎮ
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