Page 163 - 《广西植物》2025年第3期
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3 期                  刘宝骏等: 文采报春苣苔 PwDREB2s 基因的克隆与表达分析                                       5 4 3

                  ( Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrainꎬ Guangxi Institute of Botanyꎬ Guangxi
                             Zhuang Autonomous Region and Chinese Academy of Sciencesꎬ Guilin 541006ꎬ Guangxiꎬ China )

                 Abstract: Dehydration responsive element binding protein 2 (DREB2) is a transcription factorꎬ which plays a regulatory
                 role to droughtꎬ high salinity and high temperature responding in model plants. Howeverꎬ it is still unclear for the
                 function of DREB2 genes in Primulina wentsaiiꎬ which is adapted to limestone karst habitats with drought ̄high
                 temperature environment. DREB2 homologous genes responding to dual stresses of drought and high temperatureꎬ were
                 screened in P. wentsaii. It could provide a new gene pool for the creation of resistant germplasm in Gesneriaceae. In this
                 studyꎬ specific primers were designed based on transcriptome sequences of P. wentsaii firstlyꎬ gDNA and cDNA were
                 used as templates to isolate PwDREB2 genes. Thenꎬ amino acid sequencesꎬ phylogenetic relationships and consensus
                 motifs were analyzed by bioinformatics methods. As wellꎬ the expression patterns of PwDREB2s genes were analyzed by
                 semi ̄quantitative reverse transcription PCR (sqRT ̄PCR) with single stressꎬ such as low temperatureꎬ heat shockꎬ
                 simulated drought (osmosis)ꎬ high salinityꎬ exogenous ABA and oxidationꎬ respectively. Finallyꎬ the transcript levels of
                 designated membersꎬ which could respond to single stresses and drought ̄heat shock combined stressesꎬ were detected
                 with different drought ̄heat shock patterns by quantitative real ̄time PCR (qRT ̄PCR). The results were as follows: (1)
                 Eight intron ̄lacking PwDREB2s genes were isolatedꎬ they could encode 198-386 amino acidsꎬ which contained several
                 typical characteristic regions such as AP2/ ERF domainꎬ nuclear localization signal or transcriptional activation domainꎬ
                 respectivelyꎻ (2) Transcription factorsꎬ such as PwDREB2A/ 2AL1/ 2AL2ꎬ PwDREB2D/ 2DL and PwDREB2F were
                 classified into subtype 1ꎬ subtype 2 and subtype 3 of A ̄2 subgroupꎬ respectivelyꎬ while PwDREB2EL1/ 2EL2 were
                 classified into A ̄6 subgroupꎻ (3) Semi ̄quantitative RT ̄PCR analysis showed that the transcript levels of PwDREB2s
                 genes were induced by a series of single stressesꎬ among which PwDREB2A/ 2AL1/ 2AL2/ 2D genes could simultaneously
                 respond to simulated drought and heat shockꎻ (4) qRT ̄PCR results revealed that the PwDREB2D geneꎬ which was
                 responding to drought ̄heat shock combined stressesꎬ was tissue ̄specificꎬ it could only be strongly induced in
                 rhizomes. Compared with mock groupꎬ the transcriptional responses of PwDREB2A/ 2AL1/ 2AL2 genes were significantly
                 enhanced under natural drought ̄heat shock combined stresses with soil matrixꎬ except for PwDREB2D gene. Howeverꎬ
                 when it was compared with the single stress of natural drought and heat shockꎬ the expression levels of PwDREB2AL1/
                 2AL2 genes were significantly higher in natural drought ̄heat shock combined stresses. In conclusionꎬ PwDREB2AL1/
                 2AL2 genes may play the important regulatory role in response to dual stresses of natural drought and high temperature in
                 P. wentsaii.
                 Key words: Primulina wentsaiiꎬ DREB2 transcription factorꎬ fleshy leafꎬ drought ̄heat shock combined stressesꎬ
                 expression pattern




                随着全球沙漠化、气候变暖进程的加快ꎬ干旱                           典型结构特征包含 DNA 结合结构 域、转 录 调 控
            与高温对植物生长发育造成的不利影响日益显                               区、寡聚化位点及核定位信号( nuclear localization
            著ꎮ 许多植物进化出了一系列适应干热胁迫的特                             signalꎬ NLS ) 等 ( Lata & Prasadꎬ 2011 )ꎮ 基 于
            定机 制ꎬ 以 在 恶 劣 的 环 境 中 生 存 和 维 持 生 长                AP2 / ERF 结构域的相似性ꎬDREB 转录因子可进
            (Cramer et al.ꎬ 2011)ꎬ揭示植物适应干热环境的                  一步分为 6 个亚组ꎬ分别命名为 A1-A6ꎮ 其中ꎬA1
            遗传基础ꎬ对增强植物抗性与制定种质资源保护                              与 A2 亚组成员能在 ABA 不依赖途径中发挥作
            策略至关重要ꎮ 目前ꎬ与单独干旱或高温胁迫应                             用ꎬ而 A3-A6 亚组成员胁迫应答受 ABA 依赖途径
            答相关的分子机制已有大量报道ꎬ但对干旱和高                              的调控( Sakuma et al.ꎬ 2002)ꎮ A ̄1 与 A ̄4 亚组、
            温 胁 迫 联 合 响 应 的 研 究 则 相 对 较 少ꎮ DREB                A ̄2 与 A ̄3 亚组分别享有共同的保守结构域ꎬ表明
            (dehydration responsive element binding protein) 转  它们可能有共同的起源(Nakano et al.ꎬ 2006)ꎮ A ̄
            录因子隶属于 AP2 / ERF 家族 DREB 亚族ꎬ被认为                    2 亚组成员又称 DREB2 转录因子ꎬ在响应脱水与
            能够广泛参与植物对非生物胁迫的应答调控ꎬ其                              热胁迫中尤为重要( Xu et al.ꎬ 2011)ꎮ 该亚组又
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