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以茶树(Camellia sinensis)大叶且无蕾不开花的突变体‘大叶龙’及其母株为材料,通过同源克隆结合RACE-PCR方法,克隆了LEAFY(LFY)同源基因的全长c DNA序列,两种序列分别命名为Cs LFL1和Cs LFL2,其c DNA全长分别为1 448和1 466 bp,各自包含1 191和1 197 bp的完整开放阅读框,编码396和398个氨基酸。它们与漆树科、无患子科以及壳斗目(山毛榉目)一些物种的LFY同源序列具有77%~79%的一致性,具有植物LFY成员作为转录因子的脯氨酸富集区、亮氨酸重复、酸性和碱性结构域以及保守的C–端等典型结构特征。系统发育分析表明,它们属于双子叶植物LEAFY分支,并且亲缘关系最近,说明两者的形成是发生在茶树物种进化过程中较晚期的复制事件。两种序列在正常开花母株及‘大叶龙’中没有区别,在母株花芽中强烈表达,在母株和‘大叶龙’叶芽中有微弱表达。这些结果说明Cs LFL1和Cs LFL2代表了茶树中LFY的同源基因,并且可能参与茶树的成花启动过程。
The full-length LEAFY (LFY) homologous gene was cloned by homologous cloning and RACE-PCR from the large-leaved and non-flowering mutant “Da Ye Long” and its mother plant of Camellia sinensis c DNA sequences. The two sequences were named as Cs LFL1 and Cs LFL2, respectively. The full-length cDNAs of c DNA were 1 448 and 1 466 bp respectively, which contained 1 191 and 1 197 bp complete open reading frames, encoding 396 and 398 amino acids . They are 77% -79% identical to the LFY homologous sequences of some species of Asclepiadaceae, Sapindaceae, and Ocimumidae (Fagaceae), have proline-rich regions of plant LFY members as transcription factors, are bright Amino acid repeats, acidic and basic domains, and conserved C-termini. Phylogenetic analysis showed that they belonged to the LEAFY branch of dicotyledonous plants, and the closest genetic relationship, indicating that the formation of the two is occurred in the evolution of tea plant species during the late replication events. The two sequences were indistinguishable between the normal flowering mother plant and the ’big eel dragon’ and were strongly expressed in the flower buds of the mother plant and weakly expressed in the mother plant and leaf buds of the ’big leaf dragon’. These results indicate that Cs LFL1 and Cs LFL2 represent homologous genes of LFY in tea plants and may be involved in flowering initiation of tea plants.