油棕脱落酸受体PYL基因家族的全基因组鉴定及表达分析

Genome-wide identification and expression of abscisic acid receptor PYL gene family in oil palm

  • 摘要: 【目的】鉴定油棕(Elaeis guineensis)脱落酸(ABA)受体PYR/PYL/RCARs (PYL)基因家族成员,分析其表达特性,为探究ABA信号通路在油棕果肉成熟过程中的功能研究提供理论依据。【方法】以拟南芥和水稻的PYL蛋白氨基酸序列作为参考序列,通过BLASTp比对及保守结构域预测分析从油棕基因组中鉴定出PYL基因家族成员,利用生物信息学软件对其染色体定位、基因结构、启动子顺式作用元件及编码蛋白的理化性质、保守结构域、进化关系进行分析,并采用实时荧光定量PCR对PYL家族基因在不同组织、不同发育期果实及外源ABA处理下的表达特性进行检测。【结果】从油棕基因组中共鉴定出12个油棕PYL基因家族成员(EgPYL1~EgPYL112),分布在8条染色体和1个Scaffolds上,含有1~3个外显子,开放阅读框(ORF)为564~765 bp,编码187~254个氨基酸,蛋白分子量为20.95~28.33 kD,等电点(pI)为5.26~7.95,不稳定指数为32.67~52.87,脂溶指数为73.87~87.60,总平均亲水性为-0.68~-0.17。12个PYL家族蛋白均含有特征结构域PYR/PYL/RCAR,分为3个亚族。EgPYL1EgPYL6基因具有共线性,EgPYL4、EgPYL5、EgPYL9EgPYL11基因具有共线性。EgPYLs基因的启动子上含有大量植物激素响应元件、逆境胁迫响应元件和光响应元件。EgPYLs基因在根、茎尖、叶、花和果肉中均有表达,但表达量差异较明显。EgPYL7、EgPYL8EgPYL9基因的表达量随果肉成熟度增加逐渐升高,在23周达峰值。11个Eg PYLs基因均受外源ABA诱导表达。【结论】大多数PYL基因家族成员参与油棕对ABA的响应,且部分成员(如EgPYL7、EgPYL8EgPYL9)在油棕果实发育中发挥重要的调控作用。

     

    Abstract: 【Objective】In this research, the oil palm(Elaeis guineensis) abscisic acid receptor PYR/PYL/RCARs(PYL) gene family members were identified, and their expression characteristics during fruit development and abscisic acid(ABA) treatment were analyzed, which provided evidence for researching the mechanism of ABA signaling pathway in fruit maturation of oil palm.【Method】The amino acid sequences of Arabidopsis and rice PYL protein were query sequences, identified PYL gene family members from oil palm genome via BLASTp and conservative domain prediction analysis. The chromosomal location, gene structure, promoter cis-acting elements, protein physicochemical properties, conserved functional domains and evolutionary relationships were analyzed through bioinformatics softwares. The expression characteristics of PYL family gene in different, mesocarp at different stages and ABA treatment were analyzed by real-time fluorescence quantitative PCR.【Result】The results showed that 12 PLY(EgPYL1-EgPYL12) gene family members were identified form oil palm genome and were distributed on 8 chromosomes and 1 Scaffolds. The extrons numbers of EgPYL family members were between 1 and 3, the open reading frames(ORF) length were between 564 and 765 pb and encoded amino acid numbers were between 187 and 254. The molecular weights were between 20.95 and 28.33 kD, the isoelectric points were between 5.26 and 7.95, the instability indexes were between 32.67 and 52.87, the aliphatic indexes were between 73.87 and 87.60, the total hydrophilicity was between-0.68 and-0.17. Twelve PYL family protein contained PYR/PYL/RCAR functional domain and were divided into 3 groups based on phylogenetic relationships. Collinearity analysis showed that collinearity existed between EgPYL1 gene and EgPYL6 gene, EgPYL4 gene, EgPYL5 gene, EgPYL9 gene and EgPYL11 gene. A large number of plant hormone responses, stress responses and light responses elements were identified on promoters of EgPYLs gene. Expression analysis of different tissues showed that the EgPYLs gene expressed in roots, shoots, leaves, flowers and fruits, with great difference. During fruit maturation, the expressions of EgPYL7, EgPYL8 and EgPYL9 genes increased gradually and reached the peak at 23 weeks after anthesis. Eleven EgPYLs were induced by exogenous ABA treatment.【Conclusion】Most PYL gene family members are involved in responding to abscisic acid, among them EgPYL7, EgPYL8 and EgPYL9 genes might play important roles in regulating oil palm mesocarp development.

     

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