陆地棉H+-PPase基因家族全基因组鉴定及表达分析

Genome-wide identification and expression analysis of H+-PPase gene family in Gossypium hirsutum

  • 摘要: 【目的】鉴定陆地棉跨膜质子泵焦磷酸酶(H+-PPase)基因家族成员,并分析其表达模式,为探究该家族基因的功能和调控机制及优质纤维棉育种提供理论依据。【方法】从Pfam数据库获取H+-PPase基因家族(PF03030)的隐马尔可夫模型文件,从陆地棉基因组中筛选包含H+-PPase家族保守结构域的成员,运用生物信息学方法对其理化性质、进化关系、基因定位、共线性关系、基因结构、顺式作用元件和表达模式进行分析,并利用实时荧光定量PCR检测10个在棉纤维发育中表达的侯选基因表达情况。【结果】从陆地棉全基因组水平上鉴定出20个H+-PPase基因家族成员(GhH_PPase1~GhH_PPase20),分布在12条染色体上,基因长度为2531~11810 bp,编码的氨基酸残基数为575~803个,蛋白分子量为60087.76~85197.58 Da,均为疏水性的酸性蛋白,可分为亚族Ⅰ (4个)、亚族Ⅳ (4个)和亚族Ⅴ (12个)三大分支。片段复制事件是陆地棉H+-PPase基因家族扩张的主要驱动力,位于染色体A05和D05上的H_PPase1、H_PPase2、H_PPase11H_PPase12可能是进化过程中种间传播的主要基因,且陆地棉基因与单双子叶植物的共线性均较低,可能经历了独立的进化事件。有14个GhH_PPases蛋白含有10个保守基序,且排列顺序完全相同;其余6个基因的保守基序差异较明显,可能具有不同的功能。20个GhH_PPases基因启动子区域存在大量光响应元件、胁迫响应元件和激素反应元件。陆地棉H+-PPase基因家族成员的表达具有时空特异性,且相对于其他亚家族,亚族Ⅴ的较多基因在棉花纤维发育过程中发挥更重要的作用。【结论】陆地棉H+-PPase基因家族发生了一定程度的功能分化,多种响应元件协同参与生长发育和逆境应答,部分基因在陆地棉纤维伸长期和次生壁加厚期发挥重要的调控作用。

     

    Abstract: 【Objective】 This paper identified the members of transmembrane proton pump pyrophosphatase(H+-PPase) gene family in Gossypium hirsutum, and analyzed their expression patterns to provide a theoretical basis for exploring the function, regulation mechanism, and high-quality fiber cotton breeding of this gene family.【Method】 Hidden Markov Model Files(HMM) of the H+-PPase gene family(PF03030) were obtained from the Pfam database. G. hirsutum genome was screened for members containing the conserved domains of the H+-PPase family. Bioinformatics methods were applied to analyze their physicochemical properties, evolutionary relationships, gene localization, collinearity relationships, gene structure, cisacting elements, and expression patterns. Finally, the expression levels of 10 candidate genes involved in cotton fiber development were detected by using real-time fluorescence quantitative PCR.【Result】 Twenty members of H+-PPase gene family(GhH_PPase1-GhH_PPase20) were identified at genome-wide level of G. hirsutum, of which distributed on 12 chromosomes with gene lengths ranging from 2531 to 11810 bp, the number of encoded amino acids residues ranging from 575 to 803, and the protein molecular weight ranging from 60087.76 to 85197.58 Da. All members were hydrophobic and acidic proteins. They could be divided into three major branches:subfamily I(4 members), subfamily IV(4 members) and subfamily V(12 members). Segmental duplication events were the main driving force for the expansion of the G. hirsutum H+-PPase gene family. H_PPase1, H_PPase2, H_PPase11 and H_PPase12 on chromosomes A05 and D05 were likely to be the main genes involved in interspecific transmission during evolutionary process. Meanwhile, the collinearity of genes between G. hirsutum and monocot and dicot plants was relatively low, indicating possible independent evolutionary events. There were 14 GhH_PPases proteins contained 10 conserved motifs arranged in the same order, while the remaining six genes showed great differences in their conserved motifs, suggesting potential functional divergence. The promoter regions of the 20 GhH_PPases genes contained numerous light-responsive elements, stress-responsive elements, and hormone-responsive elements. The expression of G. hirsutum H+-PPase gene family exhibited temporal and spatial specificity, and more genes insubfamily V played a more important role in cotton fiber development compared to that of other subfamilies.【Conclusion】 The G. hirsutum H+-PPase gene family undergoes a certain degree of functional differentiation. Various responsive elements cooperate in growth, development, and responses to adversity. Some genes play important regulatory roles during the elongation and secondary wall thickening stage of G. hirsutum fibers.

     

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