【摘要】 棕色棉具有典型的自然棕色纤维,在纺织及加工过程中无需漂染,是真正的"生态"、"环保"棉。克隆并了解棉花纤维棕色素合成相关基因对于揭示棉花纤维色素发育的分子机理具有重要的意义。本研究选取亚洲棉(Gossypium arboreum)棕色纤维慈溪紫棉和白棉余姚中棉纤维发育不同阶段RNA,采用Gene Fishing技术,获得1条仅在亚洲棉棕色棉纤维中特异表达的约500bp的PCR扩增产物,根据测序结果和生物信息学分析发现,该基因在核苷酸序列上与拟南芥(Arabidopsis thaliana)种皮棕色素合成TT12基因存在76%的序列同源性。随后利用RT-PCR的方法克隆了该基因,命名为GaTT12a(GenBank登录号:JX013908),该基因编码490个氨基酸残基,分子量约52.7kD,属于MATE超基因家族中的一个成员。利用荧光定量PCR分析了GaTT12a基因在发育不同阶段纤维、种皮的表达特征,结果表明,GaTT12a基因在棕色纤维、白色棉种皮和棕色棉种皮中均优势表达,在白色棉纤维中几乎不表达,说明该基因参与纤维棕色素的形成,结果暗示棉花种皮棕色素和纤维棕色素可能分享相似的合成代谢途径。研究结果为进一步了解GaTT12a基因参与棕色棉纤维色素形成、棕色棉纤维色素与种皮棕色素合成之间的关系提供了基础研究资料。更多还原

【Abstract】 Brown cotton processes the natural brown fiber color, without dyeing during spinning and processing process, which is really the "ecological", "environmental protection" cotton. Molecular cloning and understanding of the brown pigment synthesis-related gene in cotton fiber is very important to reveal molecular mechanism in the formation and accumulation of brown pigment. The brown fiber Asian cotton (Gossypium arboreum) Cixizimian and white fiber Yuyaozhongmian were selected in this study. Cotton fiber total RNA was extracted from the cotton fiber different development period. Ultimately, only one expressed fragment of 500 bp was obtained from the cDNA of brown cotton fiber. With sequencing and bioinformatics analysis, one gene named GaTT12a (GenBank accession number: JX013908) was cloned using the RT-PCR method. The sequence of the gene showed 75% homologous with testa brown pigment synthesis TT12 gene of Arabidopsis thaliana in amino acid sequence. The gene encoded 490 amino acid residues with the molecular weight of 52.7 kD, belonging to MATE super-gene family. Real-time quantitative PCR analysis of the gene showed that the gene presented super-dominant expression both in the brown cotton fiber, testa of brown and white cotton, while which not detected in white fiber. The result indicated that The GaTT12a gene was involved in the formation of brown pigment in cotton fiber, the result further suggested that there was the same synthesis metabolic pathway of the brown pigment in both testa and fiber. The above result gives the fundamental information for further understanding its function participating in the formation of brown pigment of cotton, the relationship of brown pigment of cotton fiber and brown pigment of seed coat.更多还原