对一个新发现的棉纤维突变体的鉴定及特性分析

在农杆菌介导的转基因组织培养再生后代中发现了一个无绒有絮的纤维发育突变体,通过自交选择T₃代获得其纯合体,命名为CM突变体。尽管CM突变体从转基因后代中发现,但和转基因插入位点无关,推测是在组织培养过程中产生的点突变所致。通过与陆地棉遗传标准系TM-1,海岛棉军海1号,以及新乡小吉无绒有絮(XinFLM),新乡小吉无绒无絮(XinWX),徐州142无绒无絮(XZ142WX),显性光子N1N1,隐性光子n2n2、SL-7-1、MD17及T586等一系列纤维发育突变体分别配制F₂组合进行突变基因的遗传及等位性分析,结果表明CM突变体与纤维发育正常的TM-1和军海1号杂交,F₁表型均为无绒有絮,F₂表现无绒有絮和有绒有絮3∶1分离,说明该突变体与纤维发育正常材料相比,在短绒发育方面存在一个位点的差异,该突变性状由单显性基因控制。等位性测验及分子定位均表明, 控制该突变体短绒的基因与控制N1N1显性光子的N1基因等位。扫描电镜进一步证明该基因突变会造成纤维起始突起延迟。与N1N1突变体相比,CM突变体的衣分比N1N1显著高,而百粒重比N1N1极显著低。推测CM突变体中的突变基因与显性N1基因为复等位基因。

Identification and Characterization of a Novel Fiber Mutant from Transgenic Progeny in Gossypium hirsutum L.

The discovery and identification of the fiber mutant has been vital for genetic and functional genomic research in cotton. In this study, we found a linted-fuzzless fiber mutant in transgenic cotton by Agrobacterium-mediated transformation path, the pure line of the mutant was obtained in T₃ generation. We named the novel fiber mutant as CM mutant. PCR analysis showed that the mutation trait had no relationship with T-DNA insertion, but was deduced to be caused by point mutation in the process of tissue culture. Analysis of inheritance and allelic tests were conducted by crossing CM mutant with TM-1, Junhai1, and a series of fiber developmental mutants such as XinFLM, N1N1, n2n2, and T586 with linted-fuzzless fiber and XinWX, XZ142WX, SL-7-1, and MD17 with lintless-fuzzless fiber, respectively. Of above 10 combinations, the F₁ were fuzzless, and F₂ generations of CM×TM-1 and CM×Junhai1, all showed the separation ratio of 3:1 of linted-fuzzless to linted-fuzzed phenotypes. Based on the genetic analysis, we indicated that there was one dominantly different locus between the mutant and TM-1or Junhai1. Allelic tests and gene mapping all showed that the fuzzless gene of the mutant was allelic to N1, dominantly controlling naked-seed trait. Scanning electron microscopy (SEM) analysis was conducted to investigate the development of fiber cell initials in CM mutant during early developmental stages (0–3 DPA). Just like N1N1 mutant, the mutation gene could result in the process of fiber cell formation and elongation delayed. Compared to N1N1, the lint percentage of CM was significantly higher and 100-seed weight was significantly lower. In conclusion, we speculate on that the mutation gene in CM is one of multiple allele genes of dominant naked-seed N1, and the result also shows the mutation reproducibility for fiber development in different cotton materials.