海岛棉茎秆茸毛性状的遗传与基因定位

Researches have shown that cotton stalk trichome and seed fiber both originated from single epidermal cell and they are subject to similar metabolic pathways regulation. Therefore, to figure out the genetic law of the initiation and development of stalk trichome has a positive guiding role to reveal the molecular mechanism of growth and development of cotton fiber. The island cotton provides excellent raw materials for the textile industry because of its high quality fiber. However, there are rarely reports on the genetic regularity and molecular mechanism of the initiation and development of trichome and fiber of the sea island cotton. Our laboratory has made detailed observation and found that there are mainly two types of trichome distribution of the island cotton: clustering and short fine. Additionally, we also found that the sea island cotton without trichome simultaneously had rarely staple fibre covering its seed surface, from which we inferred that the generation of the island cotton stalk trichome and seed fiber on the surface may be regulated by one of the same metabolic pathway regulation. The project intends to study the genetic characteristics of the island cotton stalk trichome, using various methods such as conventional crossing, genomics and molecular biology, fine mapping the location of the trichome genes on chromosome, clone candidate genes by chromosome walking, preliminary verify the gene functions and so on. Our research contributes not only to lay a theoretical foundation in the molecular mechanism of island cotton stalk trichome and seed fiber, but also to provide new more genes for breeding cotton varieties with high yield and quality, and rich cell growth and development theory.

研究表明棉花茎秆茸毛和种子纤维都是由单个表皮细胞延伸而来，受类似的代谢途径调控。因此，明确棉花茎杆茸毛产生的遗传规律对于揭示棉花纤维生长发育的分子机理具有一定的指导作用。海岛棉的纤维品质优异，是纺织高档纱的优质原材料。然而，有关海岛棉茸毛和纤维产生遗传规律和分子机理的研究很少见报道。本实验室在对棉花茎秆茸毛的系统观察中发现海岛棉茎秆茸毛主要有成簇和短细密两种类型。此外，我们还发现没有茸毛的海岛棉其种子表面基本也没有短纤维。由此推断海岛棉茸毛和其种子表面纤维的产生可能受其中一条相同代谢途径调控。本项目将利用常规杂交，基因组学和分子生物学等方法研究海岛棉茎秆茸毛产生的遗传特性,精细定位茸毛基因在染色体上的位置，通过染色体步移克隆候选基因，并进行初步功能验证等，为研究海岛棉茎秆茸毛和种子纤维产生的分子机理奠定理论基础，还可为选育优质高产棉花新品种提供新基因，并丰富细胞生长发育的理论。

棉花茸毛有利于抵御各种生物及非生物因素造成的伤害，且研究棉花茸毛的遗传基础及调控机制可为研究棉花纤维生长发育的分子机理奠定基础。前期我们经过多年观察研究发现陆地棉和海岛棉的茎秆茸毛类型差异明显，陆地棉大部分是有茸毛，少部分是无茸毛的，海岛棉则相反。本课题组把陆地棉茎杆茸毛分为Ⅰ型和Ⅱ型，把海岛棉茸毛分为Ⅲ型和Ⅳ型。并且在此基础上配置了四个不同杂交组合，并用它们的F2代群体构建了Chr. 6和Chr.24染色体的遗传连锁图谱，定位了不同类型茎秆茸毛的相关基因或QTL。I型茎秆茸毛这一表型是由多基因调控的数量性状，在Chr.6和Chr.24上分别检测到一个LOD值为5.92和7.97的QTL。II型茎秆茸毛这一表型是由单基因控制的质量性状，该基因命名为T1基因且定位在Chr.6上。III型茎秆茸毛这一表型是由多基因调控的数量性状，只在Chr.24上检测到一个LOD值为12.83的QTL。IV型茎秆茸毛这一表型是由单基因控制的质量性状，该基因命名为Tri基因且定位在Chr.24上。目前对茎秆茸毛密度起始的调控过程及遗传规律还不甚了解，因此对不同类型茎秆茸毛表型的遗传规律进行系统的研究，为更进一步克隆调控棉花茎秆茸毛表型相关基因奠定基础。