摘要： 为了研究番茄SlYAB2a基因的功能及其在番茄生长发育中的分子机理，以番茄的cDNA为模板，利用RT-PCR技术从番茄中克隆到SlYAB2a基因，该基因编码的蛋白质由192个氨基酸残基组成，蛋白质的分子量为21.35 kDa，等电点是8.79，平均亲水系数是-0.487。SlYAB2a蛋白质的6～165位氨基酸残基形成Pfam：YABBY结构域，在20～47位有1个C₂C₂锌指结构域，在122～181位有1个螺旋-环-螺旋结构域。二级结构分析表明SlYAB2a蛋白分子中，α-螺旋占19.79%、β-折叠占14.06%、其余66.15%为不规则卷曲。蛋白多序列比对表明SlYAB2a与马铃薯、林烟草、酿酒葡萄、大豆、拟南芥、甘蓝型油菜、花药野生稻、玉米和小麦YABBY2的一致性分别为98%，78%，71%，65%，64%，64%，58%，57%，57%，说明SlYAB2a蛋白与来源于双子叶植物的YABBY2一致性较高，而与来源于单子叶植物的一致性较低。通过聚类分析发现YABBY2蛋白明显分为单子叶和双子叶2个亚类，SlYAB2a蛋白属于双子叶亚类，与马铃薯、潘那利番茄、绒毛状烟草、林烟草等的YABBY2蛋白序列亲缘关系较近。实时定量RT-PCR分析结果表明，在番茄植物的不同生长发育时期，根、茎、叶、花、果实中，都有SlYAB2a基因表达；并且在花和青熟果实中，SlYAB2a基因表达水平远远高于其他组织。说明SlYAB2a基因在花和果实的发育过程中起着重要作用。洋葱表皮细胞瞬时表达结果表明SlYAB2a蛋白定位于细胞核中。

关键词: 番茄, SlYAB2a, 基因克隆, 表达分析, 亚细胞定位

Abstract: In order to study the function and molecular mechanism of SlYAB2a in growth and development of tomato.The cDNA sequence of SlYAB2a was cloned from tomato by RT-PCR.Bioinformatics analysis showed that SlYAB2a encodes a putative polypeptide of 192 amino acids with a calculated molecular mass of 21.35 kDa,a theoretical pI of 8.79,and a grand average of hydropathy value of-0.487.SlYAB2a protein was predicted to possess a Pfam:YABBY domain architecture at position 6-165,a C₂C₂ zinc finger-like domain at position 20-47,and a helix-loop-helix domain at position 122-181.Secondary structure analysis revealed that SlYAB2a protein contains 19.79% α-helical domains,14.06% β-sheet domains,and 66.15% random coil.The analysis of protein multiple sequence alignments showed that the percent identity of the SlYAB2a with members of group YABBY2 from Solanum tuberosum,Nicotiana sylvestris,Vitis vinifera,Glycine max,Arabidopsis thaliana,Brassica napus,Oryza brachyantha,Zea mays and Triticum aestivum were 98%,78%,71%,65%,64%,64%,58%,57% and 57%,respectively;which suggested the percent identity of the SlYAB2a with other members of group YABBY2 from dicotyledon was higher than that from monocotyledon.The analysis of phylogenetic relationship showed that YABBY2 was easily separated into two distinct subgroups,that was dicotyledon subgroup and monocotyledon subgroup.SlYAB2a belonged to dicotyledon subgroup and was most closely related to members of group YABBY2 from Solanum tuberosum,Solanum pennellii,Nicotiana tomentosiformis and Nicotiana sylvestris. The expression of SlYAB2a was determined by Real-time quantitative RT-PCR.The result showed that the SlYAB2a gene was transcribed in different tissue organ.The expression level of SlYAB2a in flowers and mature green fruits was much higher than that in any other analyzed tissue organs.These results suggested that SlYAB2a might be involved in flower and fruit development.Following transient expression of SlYAB2a in onion epidermal cells,SlYAB2a was found to be localized in the nucleus.

Key words: Tomato, SlYAB2a, Gene cloning, Expression analysis, Subcellular localization

中图分类号: 

• Q78

• S641.03