【摘要】 MYB类转录因子是指含有MYB结构域的一类转录因子,广泛参与植物发育和代谢调节。含2个MYB结构域的R2R3类MYB转录因子在植物体内主要参与次生代谢的调节和控制细胞的形态发生。从优质材料7235不同发育时期的棉纤维混合cDNA文库中克隆了一个棉花MYB转录因子基因GhTF1(GenBank登录号:EF651783)。该cDNA序列长1115bp,其开放读码框长度为771bp,编码256个氨基酸。表达特征分析表明,该基因在陆地棉7235不同组织中均表达,但表达量不同,特别在开花前1d,开花后8d和11d的纤维细胞中优势表达。该基因在二倍体棉种非洲棉和雷蒙德氏棉中开放读码框区的序列较保守,但在非编码区差异较大,在内含子区存在大片段插失和碱基替换现象。Southern杂交结果表明该基因在陆地棉基因组中存在2个拷贝,推测A、D亚组中各有1个拷贝。利用海7124和TM-1两亲本配置的BC1作图群体,将GhTF1定位在染色体10上。更多还原

【Abstract】 Plant MYB transcription factors are characterized by containing a structurally conserved MYB domain, they play important roles in the regulation of plant development and metabolism. Of them, the R2R3 MYB proteins with two MYB domains are involved in regulating secondary metabolism and cellular morphogenesis. Cotton fibers are single-celled seed trichomes. So far, the molecular process of fiber initiation is poorly understood. However, some transcriptional factors such as MYB genes are responsible to fiber cell initiation. Just like in Arabidopsis, leaf trichome formation is mediated through positive and negative regulators such as GL1 and GL2 encoding MYB transcription factors. In cotton, several MYB transcription factors have been cloned. Expression of type I genes (GhMYB1, 2, and 3) was detected in all tissues tested, while type II genes (GhMYB4, 5, and 6) process involving many other pathways such as signal transduction and transcriptional regulation. Moreover, GhMYB109, a gene encoding a R2R3 MYB transcription factor, was expressed specifically in fiber initials and elongating fibers. And over-expression of GaMYB2 complemented gl1 phenotype as well as induced seed trichome development in Arabidopsis, suggesting a role of MYB-like transcription factors in cotton fiber cell differentiation. The objective of the study was to clone new MYB genes, further put a foundation to illustrate these genes function in cotton fiber developmental stages. In this paper, a MYB transcription factor gene, GhTF1 was isolated from developmentally different cotton fiber pools of elite material 7235 library. GhTF1 (GenBank No.:EF651783) is a 1 115 bp cDNA, its open reading frame is 771 bp, and encodes a polypeptide containing 256 amino acids. GhTF1 was expressed constitutively in every tissue with different expression levels, e.g. with higher levels in fiber cells at initiation and elongations stages. GhTF1 had conserved coding region in A and D diploid cotton species, G. herbaceum and G. raimondii, however, there existed a large DNA fragment insertion/deletion and base substitutions in their corresponding intron region. Southern blotting analysis showed that there were two copies of GhTF1 in the genome of upland cotton, deducing that the sub-genome A and sub-genome D contain each of them. Using the BC1 mapping population derived from the hybridization between the upland cotton standard line TM-1 and G. barbadense cultivar Hai7124, and TM-1 as recurrent parent, GhTF1 was located on the chromosome 10.更多还原