基于转录组的荔枝GRF基因家族的鉴定及表达分析

Identification and Expression Analysis of GRF Gene Family Based on Transcriptome Data in Litchi(Litchi chinensis Sonn.)

GRF转录因子参与多种生长发育过程,包括根、茎、叶和花的发育等。本研究基于荔枝转录组测序结果,共鉴定出22个GRF基因并分析其蛋白理化性质、系统进化、基因结构、miRNA靶基因和组织表达分析。结果表明,22个GRF蛋白的大小为72~246 aa,分子量为8 055.41~250 929.9 Da,等电点为4.96~10.44。大部分GRF蛋白为亲脂蛋白并主要定位于细胞核中。系统进化分析将其分为6类,相较于水稻,荔枝与拟南芥GRF的亲缘关系更近。22个GRF基因均含有WRC或QLQ结构域,同一类基因含有相似的基序。miRNA靶基因预测发现荔枝中有14个GRF是miRNA的靶基因,并且均通过mRNA裂解的方式抑制其表达。表达相关性分析表明,10个GRF基因与GA相关基因的表达存在显著或极显著的正相关。大部分GRF基因的表达水平在‘妃子笑’中高于‘紫娘喜’,且大部分基因在顶芽的表达水平显著高于叶。而两个品种中,LcGRF1、LcGRF20和LcGRF22的表达水平均呈现叶高于顶芽的表达模式,表明其可能参与叶的发育调控。本研究为进一步研究荔枝GRF基因的功能提供了科学依据。

GRF transcription factors are involved in a variety of growth and development processes,including root,stem,leaf and flower development.Based on the transcriptome sequencing results of litchi,22 GRF genes were identified and their protein physicochemical properties,phylogenetic evolution,gene structure,miRNA target genes and tissue expression were analyzed.The results showed that the size of 22 GRF proteins ranged from 72 aa to 246 aa,the molecular weight was 8 055.41~250 929.9 Da,and the isoelectric point was 4.96~10.44.Most GRF proteins were lipophilic and mainly located in the nucleus.Compared with rice,litchi had closer genetic relationship with Arabidopsis GRF.All 22 GRF genes contained WRC or QLQ domains,and they had similar motifs.miRNA target gene prediction showed that 14 GRF genes were mi RNA target genes in litchi,and their expression was inhibited by mRNA cleavage.Expression correlation analysis showed that there was significant or extremely significant positive correlation betwe en the expression of 10 GRF genes and GA related genes.The expression levels of most GRF genes in ’Feizixiao’ were higher than those in ’Ziniangxi’,and the expression levels of most GRF genes in apical buds were significantly higher than those in leaves.In the two cultivars,the expression levels of LcGRF1,LcGRF20 and LcGRF22 were higher in leaves than in apical buds,indicating that they may be involved in the regulation of leaf development.This study provides scientific evidence for further study on the function of GRF genes in litchi.