Page 145 - 《广西植物》2025年第7期
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7 期         王嘉琪等: 冬枣 cDNA 三框表达文库构建及 ZjRWD40 基因上游调控因子的筛选                                   1 3 3 7

            ( 1. School of Biological Science and Engineeringꎬ North Minzu Universityꎬ Yinchuan 750021ꎬ Chinaꎻ 2. Innovation Team for Genetic Improvement
                of Economic Forestꎬ Yinchuan 750021ꎬ Chinaꎻ 3. Gansu Liancheng National Nature Reserve Administrationꎬ Lanzhou 730333ꎬ China )

                 Abstract: Zizyphus jujuba cv. Dongzaoꎬ a late ̄maturing fresh ̄eating jujube variety unique to Chinaꎬ features tender
                 fleshꎬ abundant juice and minimal residues. It is not only nutritionally rich but also has the value of serving as a
                 medicinal substituteꎬ making it highly popular among consumers. DNA methylationꎬ as an important epigenetic
                 modification methodꎬ plays a core role in plants response to stress and the process of fruit development. RWD40 protein
                 is a key protein involved in the methylation regulation pathway. It affects the expression of a series of downstream genes
                 by regulating the DNA methylation levelꎬ and thus has a profound impact on the development process of fruitsꎬ the
                 synthesis and accumulation of flavor substancesꎬ etc.ꎬ ultimately affecting the fruit quality. In order to reveal which
                 upstream protein regulates the expression of RWD40 gene remains unclearꎬ this study employed the yeast one ̄hybrid
                 technique to preliminarily screen for upstream candidate regulatory factors of the ZjRWD40 gene. The results were as
                                                                                              9         ̄1
                 follows: (1) The titer of the three ̄frame expression library of Z. jujuba cv. Dongzao cDNA reached 4×10 CFUmL ꎬ
                 and the recombination rate was 100%. (2) Stress ̄defense elements ABREꎬ MBSꎬ and TGACG ̄motif were identified
                 from the promoter region of the ZjRWD40 gene familyꎬ and bait vectors Bait1 ̄ABREꎬ Bait2 ̄MBSꎬ and Bait3 ̄TGACG ̄
                 motif were constructed through bait sequencesꎬ respectively. (3) The results of screening upstream regulatory factors
                 through yeast one ̄hybrid showed that Bait1 ̄ABRE exhibited a self ̄activation. A total of eleven gene sequences were
                 initially retrieved from the Bait2 ̄MBS and Bait3 ̄TGACG ̄motif bait vectors. Among themꎬ five gene sequences were
                 directly related to plant stress ̄resistance responses. The proteins encoded by these genes might regulated the expression
                 of the ZjRWD40 gene through interactions with the MBS element and the TGACG ̄motif elementꎬ thus affecting its DNA
                 methylation level. This study provides certain reference for the molecular network mechanism by which the ZjRWD40
                 gene regulates the fruit development of Z. jujuba cv. Dongzaoꎬ and also lays a theoretical foundation for the drought ̄
                 resistant breeding of Z. jujuba cv. Dongzao. Future research will focus on using transcriptome sequencing technology to
                 identify the downstream regulatory genes of ZjRWD40ꎬ aiming to further clarify its molecular pathway in the stress
                 regulation of Z. jujuba cv. Dongzao.
                 Key words: Zizyphus jujuba cv. Dongzaoꎬ RWD40 geneꎬ cDNA libraryꎬ yeast one ̄hybridꎬ cis ̄acting element




                冬枣 ( Zizyphus jujuba cv. Dongzao) 为 鼠 李 科      响抗旱胁迫的甲基化水平变化最显著的基因是
            (Rhamnaceae) 枣属( Zizyphus Mill.) 植 物ꎬ肉 质 细         RWD40ꎬ在水稻中ꎬ敲除 RWD40 基因的水稻植株
            嫩爽脆ꎬ汁多渣少ꎬ是中国特有的晚熟鲜食枣品种                             对干旱胁迫更为敏感ꎬ表现出叶片萎蔫早、生长受
            (陈爱香ꎬ2011)ꎮ 冬枣是一种营养丰富的水果ꎬ也                         抑制程度大等现象ꎬ进一步证明了 RWD40 基因在
            是中国最受欢迎的水果之一ꎬ在大约 6 万 hm 的耕                         植物应对干旱胁迫中的重要作用( Eryong & Boꎬ
                                                     2
                                        8                      2022)ꎮ 干旱胁迫通过影响 DNA 甲基化水平ꎬ进
            地上ꎬ 每 年 生 产 约 2. 5 × 10 kg ( Huang et al.ꎬ
            2023)ꎮ 冬枣从开花到果实成熟大约需要 3.5 个                        而影响了其遗传性状的改变ꎬ使果实品质等产生
            月ꎬ根据冬枣果皮颜色的变化可将其分为 3 个阶                            了差异(张春玉ꎬ2013)ꎮ 但是ꎬ在冬枣中具体哪些
            段ꎬ即白熟期、半红期和全红期ꎮ 枣果风味品质的                            上游因子调控 RWD40 基因响应干旱等胁迫尚不

            形成主要受水分、光照和温度等环境因素的影响ꎬ                             明确ꎬ因此探究 RWD40 的分子调节机制对冬枣抗
            然而干旱胁迫严重影响果实品质和产量ꎬ在冬枣                              旱育种有重要意义ꎮ
            果实成熟过程中ꎬ冬枣花期遇干旱则坐果率显著                                  在拟南芥中ꎬRWD40 蛋白能够作为中间体与
            下降ꎬ幼果期遭遇干旱则果实变小ꎬ生长后期遭遇                             ROS1 去 甲 基 化 酶 和 RMB1 或 RHD1 结 合 成 为
            干旱则品质降低ꎮ 干旱胁迫下ꎬ植物需要快速调                             WD40 复合体ꎬ调节去甲基化( Liu et al.ꎬ 2021ꎻ王
            整自身的基因表达模式以适应环境变化ꎬDNA 甲                            惠冉等ꎬ2024a)ꎬ因此 RWD40 基因可通过形成复
            基化作为一种重要的表观遗传修饰方式ꎬ在调控                              合体参与植物 DNA 主动去甲基化过程ꎬ进而影响
            基因表达中发挥着关键作用ꎮ 已有研究表明ꎬ影                             植物在干旱胁迫下的 DNA 甲基化状态ꎮ 近年来ꎬ
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