玉米DCL1基因鉴定及其自然等位变异分析

Identification of Maize DCL1 Gene and Analysis of Its' Natural Alleles

根据生物信息学分析,同源性克隆分离玉米DCL1候选基因,鉴定该基因组织与逆境响应等表达特征,并分析其自然等位变异。结果表明,目标候选基因全长7 408 bp,与拟南芥和水稻DCL1基因氨基酸序列高度保守,相似度分别为91%和77%。mRNA定量PCR分析表明,该基因在幼叶和吐丝期雌穗中表达丰度分别是幼茎的75.35倍和16.21倍;高盐、脱水、ABA、低氮、低磷胁迫处理条件下,幼苗中高盐和ABA处理呈下调表达,低氮和低磷处理呈显著上调表达,脱水处理无显著变化。核苷酸与氨基酸序列的保守性、组织与逆境响应差异表达特征均与拟南芥和水稻等相似。87份玉米自交系10×全基因重测序数据分析结果表明,该基因遗传变异丰富,共83个位点存在自然变异,但外显子区域和主要的功能结构域序列相对保守,约2/3的自然变异集中在内含子区域,外显子区域的27个自然变异位点只有8个位点在16个材料存在氨基酸差异。

The candidate gene for maize DCL1 was isolated based on bioinformatics analysis and characterized its expression across the different tissues of maize and in response to various abiotic stresses via real-time quantitative PCR（qRT-PCR） and identified its natural variation based on resequencing among the diverse lines. The maize DCLI candidate gene was 7408 bp. The amino acid sequence of it was 91% and 77% conserved with Arabidopsis and rice DCLI protein, respectively. QRT-PCR results indicated ZmDCL1 gene expressed in leaves at seedling stage and ears at silking stage were respectively 75.35 times and 16.21 times relative to the seedling shoots. It was up-regulated under low nitrogen or low phosphorus and down-regulated under NaCI or ABA. Based on amino acid and nucleotide sequence conservatism, expression profiles across different tissues and response to the different abi- otic stresses. The natural variation of this gene was analyzed by using the whole genomes 10Xresequencing data across 87 maize diverse lines.It indicated that there were 83 SNPs variation within ZmDCL1 among these lines. However, it was highly conservative in coding regions especially the functional domains. About two-thirds of the SNPs existed in introns, while 8 of 27 SNPs in exon region altered the amino acid.