番茄生长素应答因子SlARF8-1的分离与SlARFs表达特征分析

Identification of auxin response factor SlARF8-1 gene and characterization of expression pattern of some SlARFs in Solanum lycopersicum

根据番茄基因组序列,以cDNA为模板扩增获得1个生长素应答因子新基因,其与番茄SlARF8基因同源性高达94%,编码区全长2 535 bp,编码844个氨基酸,但这2个基因存在于番茄的不同染色体上,是区别于SlARF8的一个新基因,将其命名为SLARF8-1,NCBI登录号为HM560979.利用半定量反转录酶-聚合酶链反应(reverse transcription-polymerase chain reaction,RT-PCR)分析4种ARF基因(SlARF3、SlARF4、SlARF6和SlARF8-1)的时空表达特性,发现SlARF8-1基因在中蔬6号"番茄的5个器官(茎、叶、花前子房、花后子房和不同时期果实)中均有表达;SlARF3在叶片和子房中几乎没有表达;SlARF6在番茄叶片中表达量低,而在果实中的表达量较高;在果实发育的不同时期,4个SlARFs的表达量变化不大.利用2,4-二氯苯氧乙酸(2,4-D)和赤霉酸(GA3)处理番茄花蕾均可诱导单性结实,但外源激素并没有引起果实内SlARFs表达水平的显著改变,4个SlARFs基因在番茄单性果实中均有表达.

The full-length cDNA sequence of a new auxin response factor family gene with an open reading frame（ORF） of 2 535 bp in length was cloned,encoding a protein of 844 amino acids that was 94% homologous with SlARF8,and this new gene located on different chromosomes with SlARF8based on tomato genome data,so it was named SlARF8-1（GenBank accession number HM560979）.Then the temporal and spatial expression patterns of four ARFs genes（SlARF3,SlARF4,SlARF6 and SlARF8-1） were analyzed in tomato stems,leaves,ovaries and fruits at different development stage using semi-quantitative RT-PCR.The results showed that SlARF8-1was expressed in all tissues examined,but at a lower level in the ovary after pollination.By contrast,the transcripts of SlARF3and SlARF6were undetectable in leaf and ovary.These four SlARFs genes showed similar expression pattern at different stages of tomato fruit development.Furthermore,the SlARFs mRNAs levels in tomato fruits didn＇t change significantly after the ovaries were treated with exogenous hormones of 2,4-dichlorophenoxyacetic acid（2,4-D） and gibberellic acid（GA3）,which could induce significantly parthenocarpic fruits in tomato.