橡胶树无性系热研879胶乳HbPPO2基因克隆及表达分析

Cloning and expression analysis of the HbPPO2 gene in the latex of rubber tree clone Reyan 879

  • 摘要: 【目的】 克隆橡胶树无性系热研879胶乳多酚氧化酶(PPO)家族基因中的重要基因,分析其表达模式,为解析HbPPO家族基因参与橡胶树热研879乳管细胞氧化还原反应和抗逆抗胁迫应答的作用机制提供参考依据。【方法】 通过转录组数据分析,从无性系热研879胶乳HbPPO家族基因中筛选产排胶相关功能基因,克隆该基因,并对其进行生物信息学分析,研究不同割胶频率下该基因相对表达量和硫醇含量的变化,并分析二者之间的相关性。【结果】 通过转录组数据筛选获得并成功克隆到1个新的HbPPO家族基因HbPPO2HbPPO2基因编码1个偏碱性的非分泌性疏水蛋白,具有1个PPO家族特有的Tyrosinase结构域。HbPPO2基因启动子中含有与激素响应、逆境响应、光响应相关的顺式作用元件,其中逆境响应和激素响应元件中分别以厌氧诱导和茉莉酸甲酯响应元件的数量最多。HbPPO2蛋白与其他10个蛋白间的互作较强,这10个与HbPPO2蛋白互作的蛋白分别属于含铜胺氧化酶、谷草转氨酶、酪氨酸脱羧酶、苯乙醛合酶和转氨酶(待定)。编码与HbPPO2互作蛋白的基因主要富集在细胞氨基酸代谢过程、有机氮化合物代谢过程和过氧化物酶体等信号通路上。随着割胶频率的降低,HbPPO2基因相对表达量显著降低(P<0.05),胶乳硫醇含量也呈逐渐下降的趋势,胶乳硫醇含量与HbPPO2基因相对表达量的相关系数为0.87,说明二者间相关性较强。【结论】 HbPPO2基因的表达水平随着割胶频率降低而显著降低,该基因可能通过调控橡胶树乳管细胞活性氧的代谢水平影响胶乳硫醇含量,在橡胶树的产排胶生理过程中发挥重要作用。

     

    Abstract: 【Objective】 This study aimed to clone important genes in the latex polyphenol oxidase (PPO) gene family of the rubber tree clone Reyan 879 and analyze their expression patterns, so as to provide a reference for elucidating the mechanism by which HbPPO family genes participated in redox reactions, resistance, and stress responses of laticifer cells of rubber tree Reyan 879. 【Method】 The transcriptome data was analyzed to select and clone genes related to rubber production and flow in the HbPPO gene family of rubber tree clone Reyan 879. The selected gene was cloned, and the bioinformatics analysis was performed to investigate changes in relative expression and thiol content as well as the correlations between them. 【Result】 A new HbPPO family gene, HbPPO2 was identified and cloned through transcriptome data screening. The HbPPO2 gene encoded a non-secretory basic hydrophobic protein and contained one tyrosinase domain that was characteristic of the PPO family. The HbPPO2 promoters contained cis-acting elements associated with hormone response, stress response, and light response; among elements of stress response and hormone response, those of anaerobic induction and methyl jasmonate response had the highest numbers. The HbPPO2 protein exhibited strong interactions with 10 other proteins. These 10 proteins that interacted with the HbPPO2 protein belonged to copper-containing amine oxidase, glutamic-oxaloacetic transaminase, tyrosine decarboxylase, phenylacetaldehyde synthase, and potential transa-minases. The genes encoding HbPPO2 interacting protein were primarily enriched in signaling pathways related to processes such as cellular amino acid metabolism, organic nitrogen compound metabolism, and peroxisome. As the tapping frequency decreased, the relative expression of the HbPPO2 gene significantly declined (P<0.05), and latex thiol content also gradually decreased. The correlation coefficient between latex thiol content and the relative expression of the HbPPO2 gene was 0.87, indicating a strong correlation. 【Conclusion】 The HbPPO2 gene exhibits a significantly decreased expression as the tapping frequency reduces, indicating that the gene may influence latex thiol content by regulating reactive oxygen species metabolism in rubber tree laticifer cells, and thus play a crucial role in the physiological processes of rubber production and flow.

     

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