比克氏棉色素腺体形态建成与棉酚代谢特性的研究

Morphogenesis of Pigment Glands and Metabolic Characteristics of Gossypol in Gossypium bickii

【目的】对比克氏棉(G.bickii Prokh)种子形成过程和种子萌发过程中的色素腺体形态建成特点、色素腺体与棉酚含量的动态关系及其分子机理进行探究。【方法】以比克氏棉为材料,进行组织切片观察、棉酚含量测定并分析对种子萌发期色素腺体形成及棉酚合成基因的表达谱。【结果】比克氏棉在种胚形成过程中,子叶上形成大量色素腺体原,并在种子萌发后12 h形成腔体结构,转换成成熟的色素腺体;比克氏棉种胚形成过程及种子萌发过程中均未检测到棉酚,但从种子萌发12 h开始可以检测到较低含量的棉酚。种子萌发期色素腺体形成及棉酚合成相关基因表达谱分析结果表明,GoPGF基因在比克氏棉种子萌发12 h的子叶上表达量较高,与比克氏棉色素腺体形成有关;法尼基焦磷酸合成酶(FPS)基因在种子萌发24 h的子叶上表达量较高,可能与棉酚向子叶色素腺体转运有关;CYP706B1基因在种子萌发0 h较高,HMG1基因在种子萌发0 h、36 h和48 h的子叶上表达量均较高,说明这两个基因与种子萌发后色素腺体腔的形成有关,并参与棉酚的贮运;杜松烯合酶基因(CAD1-A)和HMG2基因与比克氏棉色素腺体形成无密切关系。【结论】种子萌发后的12 h为比克氏棉子叶色素腺体形态建成的关键时期,且色素腺体的形态建成与棉酚出现的时间具有同步性。GoPGF、FPS、CYP706B1、HMG1参与色素腺体的形成及棉酚的转运。

[Objective]We studied the process of pigment gland formation and the dynamic change of gossypol synthesis,the dynamic relationship and molecular mechanism between the pigment glands and gossypol during the process of embryo formation and seed germination in G.bickii Prokh.[Method]We chose G.bickii as meterial and studied the tissue section observation,determination of gossypol contents and gene expression profile analysis of pigment gland formation and gossypol synthesis genes.[Result]The results showed that a large number of pigment protoglands formed on the cotyledons during embryo development process in G.bickii.The pigment protoglands formed to cavity structure at 12 hours after seed germination,and then converted into mature pigment glands.Analysis of gene expression profiles related to the pigment gland formation and gossypol synthesis during seed germination showing that GoPGF gene was highly expressed on the cotyledons of seed germination of 12 hours,which may be related to pigment protoglands forming to cavity structure of G.bickii.Farnesyl pyrophosphate synthase gene(FPS)was highly expressed on the cotyledons of seed germination of 24 hours showing it may be associated with the gossypol transported into the cotyledon pigment glands.CYP706B1 gene was highly expressed on the cotyledons of seed germination of 0 hours and HMG1 were highly expressed on the cotyledons of seed germination of 0 hours,36 hours and 48 hours showing these genes may be associated with the formation of pigmented cavities and the storage and transport of gossypol;Cadinene synthase genes(CAD1-A)and HMG2 genes were not closely related to the pigment gland formation.[Conclusion]The 12 hours after seed germination is the key period of the morphogenesis of the pigment glands,and the morphogenesis of the pigment glands is synchrony with the time of the occurrence of gossypol in G.bickii.GoPGF,FPS,CYP706B1 and HMG1 are associated with the formation of pigmented cavities and the storage and transport of gossypol.