万寿菊类胡萝卜素裂解双加氧酶基因CCD4b的克隆与表达分析

为探讨万寿菊类胡萝卜素降解过程中CCD4b的功能,以万寿菊(Tagetes erecta L.)‘Scarletade’品种舌状花为试材,利用同源基因克隆获得CCD4b,命名为TeCCD4b (GenBank:KY450708)。序列分析表明TeCCD4b cDNA全长为1 725bp,编码区长度1 392bp,所编码的产物含463个氨基酸,主要定位于质体膜,属RPE65超家族,包含CCD家族保守的结构域;同源分析表明TeCCD4b与向日葵HaCCD4-L、案头菊CmCCD4b同源性最高;系统进化树分析显示TeCCD4b与HaCCD4-L和CmCCD4b亲缘关系最近,与其他物种的CCD4和CCD4a存在差异,表明TeCCD4b在进化过程中保守性不强,不同种属之间具有明显差异,基本符合植物的进化规律;荧光定量PCR结果显示TeCCD4b在舌状花发育过程中均有表达,且与万寿菊花色变化基本一致,表明万寿菊舌状花颜色变化可能与TeCCD4b表达量高低相关。

Cloning and expression analysis of carotenoid cleavage dioxygenase gene CCD4b in Tagetes erecta L.

CCD4b in Tagetes erecta L.,namely TeCCD4b (GenBank:KY450708),was cloned with a homologous strategy to study the function of carotenoid cleavage dioxygenase in carotenoid degradation pathway.Bioinformatics analysis showed that TeCCD4b was a member of RPE65 superfamily and mainly localized in the plasma membrane.Sequence analysis showed that the full-length sequence of TeCCD4b cDNA is 1 725 bp with a coding region of 1 389 bp,putatively encoding a peptide with 467 amino acids.Homology analysis showed that TeCCD4b,HaCCD4-L of Helianthus annuus and CmCCD4b of Chrysanthemum morifolium were highly homologous.Phylogenetic analysis suggested that there was a close relationship among TeCCD4b,HaCCD4-L and CmCCD4b,but different from CCD4 and CCD4a of other species,which indicated that TeCCD4b is not very conservative in the process of evolution,and basically in accordance with the evolution law of plant.The results of qRT-PCR demonstrated that TeCCD4b expressedalong with the development of ray florets,and was consistent with marigold color changes,which indicated the expression of TeCCD4b may associate with the color change of marigold ray floret.