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[摘要]
目的 克隆中国红豆杉altered phloem development(APL)基因, 研究APL在中国红豆杉剥皮后树皮再生过程中的表达状况, 以揭示其可能的调控作用机制。方法 利用反转录PCR(RT-PCR)方法克隆得到3个中国红豆杉APL(TcAPLs)基因的cDNA全长序列, 分别命名为TcAPL1、TcAPL2和TcAPL3, 进一步利用生物信息学工具对其进行分析, 最后利用半定量 RT-PCR对中国红豆杉不同组织和qRT-PCR技术对其剥皮再生不同时期的TcAPLs进行表达分析。结果 系统进化树结果显示, TcAPL1与TcAPL2编码的蛋白与川桑的APL蛋白亲缘关系最近, 聚为一类;TcAPL3处在APL另一个大的独立分支上。组织表达谱分析表明TcAPL1和TcAPL2 2个基因主要在根、茎、叶片和韧皮部(含形成层)中均高表达;TcAPL3在叶片中表达量较高, 而在根和木质部(含形成层)表达较低。在中国红豆杉剥皮再生过程中, TcAPL1和TcAPL2 2个基因的表达水平随着时间的延长表现为先上升后下降的趋势, 均在36 d下降最明显;TcAPL3的表达则在整个组织再生过程中被抑制。结论 克隆了3个TcAPLs基因, 3个基因在中国红豆杉剥皮再生过程中均有响应, 推测它们在中国红豆杉植物剥皮后组织再生中起一定的调控作用。
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[Abstract]
Objective To clone altered phloem development (APL) genes from Taxus chinensis and reveal their potential regulatory role in tissues regeneration after bark girdling by investigating the expression profiles of these APLs. Methods The full-length three APL genes were isolated using reverse transcription-polymerase chain reaction (RT-PCR) and were named as TcAPL1, TcAPL2, and TcAPL3, respectively. The expression profiles of these genes in different tissues and at different regeneration stages after bark girdling were analyzed by semi-quantitative RT-PCR and quantitative real-time PCR (qRT-PCR), respectively. Results Phylogenetic tree analysis suggested that TcAPL1 and TcAPL2 could be clustered together with APL protein of Morus notabilis, which are closest in genetic relationship; TcAPL3 could be clustered with APL proteins of another big independent branch. The analysis of gene expression patterns in different tissues showed that the transcript abundances of TcAPL1 and TcAPL2 were mainly expressed in the roots, stems, leaves, and phloem with cambium; While TcAPL3 was higher in the leaves than that in the roots and xylem with cambium. Through analysis of the expression patterns in regeneration tissues after bark girdling, the mRNA expressions of TcAPL1 and TcAPL2 showed a up-down trend in the following periods and were found to decrease notably at 36 d after bark girdling, while the expression of TcAPL3 was repressed at all stages after bark girdling. Conclusion In this study, three TcAPLs genes are cloned from T. chinensis, and their expressions are regulated in the regeneration processes after bark girdling. Our results demonstrate that APL might play a regulatory role in tissue regeneration after bark girdling in T. chinensis.
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[基金项目]
国家自然科学基金资助项目(31170628, 31300567)