苹果全基因组PIN成员鉴定及MdPIN15的克隆和在腋芽萌发中的表达分析

Genome-wide Identification of PIN Gene Family,Cloning and Expression Analysis of MdPIN15 During Axillary Bud Burst in Malus

从苹果金冠基因组中鉴定得到18个生长素输出载体蛋白PIN-formed(PIN),对其进行理化特性、基因结构、系统进化和启动子元件分析。结果表明,MdPIN基因家族中,含有1~14个外显子,0~13个内含子;MdPIN蛋白的保守基序数量在3~10。苹果PIN和拟南芥PIN等蛋白高度同源,且根据其进化树分为G1、G2和G3亚组;18个MdPIN在不同基因型苹果的不同器官中表达具有明显差异。以‘长富2号’为材料,从其腋芽中克隆得到一个候选基因MdPIN15,其开放阅读框为1869 bp,编码622个氨基酸。实时定量PCR表明,MdPIN15在梢尖部位表达量最高,其次是腋芽,在花芽中表达量最低;,外源GR24和Lovastatin(LVS)处理降低MdPIN15的表达量;6-BA和去茎尖处理提高了MdPIN15的表达量。MdPIN15在介导细胞分裂素(CK)、生长素(IAA)和独脚金内酯(SL)等激素调控腋芽萌发有重要作用。

A total of 18 Auxin efflux carrier protein PIN were identified from the apple genome. We further systematically analyzed its physical and chemical characteristics,gene structures,evolutionary relationships and promoter elements. Results showed that the MdPIN gene family contained 1–14 exons and 0–13 introns;3–10 conserved motifs existed in the MdPIN proteins;MdPIN and At PIN proteins were highly homologous and they could be classified into G1,G2 and G3 according to its homology. Tissue-specific expressions indicated that 18 MdPIN genes had significantly different expression patterns in different organs or tissues of different genotypes. A candidate gene MdPIN15 was separated and cloned from axillary bud of Nagafu 2. The open reading frame was 1869 bp,and it encoded 622 amino acids. Real-time quantitative PCR showed that the the highest transcription level of MdPIN15 was found in the shoot tips,the second in the axillary buds,and the lowest in the flower buds. Exogenous GR24 and Lovastatin（LVS）treatments reduced MdPIN15 expression,while it was increased by exogenous 6-BA and decapitation treatments. It seems to be possible that MdPIN15 could play a vital role in the axillary bud burst mediated by cytokinin（CK）,indole-3-acetic acid（IAA）and strigolactone（SL）.