以结球甘蓝E1为材料,提取花粉萌发前和萌发后的混合花粉总蛋白,总蛋白双向电泳后通过MALDI-TOF-MS鉴定分析差异点,根据差异点分析结果,利用同源克隆得到甘蓝BoCML49基因707bp的cDNA片段。通过对BoCML49基因的qPCR分析表明其表达量在花粉萌发前约为萌发后的2.73倍,表明BoCML49基因在花粉萌发后表达下调。通过5-Race和3-Race分别得到550bp和721bp大小cDNA片段,最终得到结球甘蓝BoCML49全长cDNA序列,开放阅读框位于125~1078bp处,加尾信号(AATAAA)位于第1222bp处。通过cDNA推导得到的氨基酸序列分析表明,BoCML49编码317个氨基酸残基,预测分子量为33.51kD,pI为6.93,经Smart-embl预测其含2个重要的EF-hand结构,分别位于序列第150~178和第216~244位氨基酸残基处,预测结果显示其含有7个α-螺旋和10个β-折叠结构。系统发育树表明结球甘蓝BoCML49与拟南芥AtCML49和AtCML50的亲缘关系较近。BoCML49基因的原核表达得到37.55kD的融合蛋白。
Calcium sensor proteins in plants play important roles in pollen germination and pollen tube growth processes. Calmodnlin-like (CML) protein of cabbage (Brassica oleracea L. var. capitata) was identified in the process of pollen germination in cabbage line E1 by two-dimensional electrophosis of the pollen total protein. The sequence of BoCML49 cDNA fragment was 707 bp. The expression analysis by qPCR showed that the BoCML49 gene was down-regulated when pollen germinated, 550 bp and 721 bp DNA fragments were obtained by 5'-Race and 3'-Race, respectively. We obtained BoCML49 gene with a total length of 1 343 bp by splicing, its open reading frame was located in the region from 125 to 1 078 bp, and contained a 124 bp 5' untranslated region (5'UTR) and a 265 bp 3'UTR, the polyadenylation signal (AATAAA) was located at 1 222 bp. The deduced BoCML49 protein contained 317 amino acids, with a MW of 33.51 kD and pI of 6.93. The structural analysis of BoCML49 though Smart-embl showed that it contained two critical functional domain EF-hand modifs, which located at the position of 150–178 and 216–244 amino acid residues, at the same time the ORF might contain seven α-helixes and ten β-sheets. The phylogenetic tree indicated that the BoCML49 had close genetic relationship with AtCML49 and AtCML50. Prokaryotic expression showed that the molecular mass of BoCML49 protein was about 37.55 kD.