桂花扩展蛋白基因家族的鉴定和表达分析

发布时间：2018-04-10 13:59

本文选题：桂花 + 扩展蛋白　；参考：《农业生物技术学报》2017年08期

【摘要】：扩展蛋白(expansin,EXP)是一类引起植物细胞壁松弛的蛋白质,在花开放过程花瓣细胞扩展中发挥重要作用。为了探究桂花(Osmanthus fragrans)中扩展蛋白基因在花开放中的表达特征,本研究从已构建的桂花品种‘堰虹桂’花芽转录组数据库中筛选得到12个与植物EXP基因同源性较高的Unigene序列,以盛开期花瓣为材料克隆得到其cDNA序列。通过NCBI数据库中的比对结果,将12个Unigene序列分别命名为OfEXPA1~OfEXPA8,OfEXPB1~OfEXPB2,OfEXLA1,OfEXLB1(Gen Bank登录号:KY968700~KY968711)。BLASTX查找比对结合ORF Finder工具分析发现,除了OfEXPA1、OfEXPA5和OfEXLB1基因的cDNA序列5′端有少量缺失外,另外9个EXP基因具有cDNA全长序列。序列分析结果表明,9个全长cDNA推导的蛋白氨基酸残基数为240~274个,预测的分子量为26.06~29.7 kD,理论等电点为4.77~9.74。桂花OfEXPA1~OfEXPA8和OfEXPB1~OfEXPB2蛋白具有典型的扩展蛋白结构特征,N端含有8个保守的半胱氨酸结构域,C端含有4个保守的色氨酸结构域,其中大部分EXPA和EXPB蛋白含有组氨酸功能域HFD基序序列。OfEXLA1具有特征基序CDQC,OfEXLB1特征基序尚未见报道。qRT-PCR分析结果发现桂花12个EXP基因在‘堰虹桂’花芽不同发育过程中均有表达,其中OfEXPA1、OfEXPA3、OfEXPA5、OfEXPA6、OfEXPA7、OfEXPA8、OfEXPB1、OfEXPB2和OfEXLB1整体表达模式较为类似,花芽发育前期(B1~B6)表达量显著高于花瓣扩展期(B7~FF),在花瓣扩展期表达量逐渐下降;而OfEXPA2、OfEXPA4和OfEXLA1在花芽发育前期表达量较低,而随着花瓣显著伸展表达量急剧增加,在花瓣扩展期呈现较高的表达。结合系统进化树分析发现OfEXPA4和OfEXPA2分别与唐菖蒲(Gladiolus grandiflorus)GgEXPA1和月季(Rosa chinensis)RhEXPA1亲缘关系较近,且OfEXPA2和OfEXPA4这两个基因与GgEXPA1和Rh EXPA1基因的表达模式相似,推测这2个基因为花开放过程中的关键EXP基因家族成员;进一步根据OfEXLA1表达特征推测其亦参与调控桂花花开放。研究结果为全面理解桂花花开放机制、扩展蛋白基因功能提供理论依据。
[Abstract]:Expansinus exp) is a kind of protein that causes cell wall relaxation in plants and plays an important role in the expansion of flower petals.In order to investigate the expression characteristics of expanded protein gene in flowering of Osmanthus fragrans, 12 Unigene sequences with high homology to plant EXP gene were screened from the flower bud transcriptional database of Osmanthus manthus Fragrans.Its cDNA sequence was cloned from petals in full bloom.The other 9 EXP genes had full length cDNA sequences.The results of sequence analysis showed that the deduced amino acid residues of 9 full-length cDNA were 240N 274, the predicted molecular weight was 26.06 ~ 29.7 KD, and the theoretical isoelectric point was 4.77 ~ 9.74.The structural characteristics of OfEXPA1~OfEXPA8 and OfEXPB1~OfEXPB2 proteins in Osmanthus Osmanthus showed that the N-terminal contained eight conserved cysteine domains and four conserved tryptophan domains.Most of the EXPA and EXPB proteins contained histidine functional domain HFD motif. OfEXLA1 had the characteristic motif CDQCnOfEXLB1. The results of qRT-PCR analysis showed that 12 EXP genes of Osmanthus osmanthus were expressed in different stages of flower bud development.However, with the increase of the expression of petal significantly, it showed a higher expression in the period of petal expansion.The phylogenetic tree analysis showed that OfEXPA4 and OfEXPA2 were closely related to Gladiolus grandiflorus)GgEXPA1 and Rosa chinensis)RhEXPA1, respectively, and the expression patterns of OfEXPA2 and OfEXPA4 were similar to those of GgEXPA1 and Rh EXPA1.We speculated that these two genes were the key members of EXP gene family in flowering process, and they were also involved in the regulation of Osmanthus fragrans blooming according to the characteristics of OfEXLA1 expression.The results provide theoretical basis for understanding the mechanism of Osmanthus fragrans blooming and expanding the function of protein gene.
【作者单位】：浙江农林大学风景园林与建筑学院;浙江理工大学建筑工程学院;
【基金】：浙江省自然科学基金(No.LQ16C160003) 浙江省教育厅科研项目(No.Y201533133) 浙江农林大学科研发展基金人才启动项目(No.2016FR031) 浙江省农业新品种选育重大科技专项(No.2016C02056-12)
【分类号】：S685.13

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