与棉纤维发育相关基因GhSAMS、GhNLP的克隆、鉴定与定位

Cloning, Characterization and Mapping of Two Genes GhSAMS and GhNLP Related with Fiber Development in Gossypium hirsutum L.

【目的】克隆陆地棉纤维伸长发育相关的基因,并做初步功能验证。【方法】以陆地棉李氏超短纤维突变体Li1li1自交后代野生型li1li1和超短纤维突变体Li1li1开花后4d的胚珠纤维复合体为探针,通过基因芯片筛选优质材料7235棉纤维伸长、次生壁加厚不同发育时期混合cDNA文库,分离出两个在两种材料中差异表达的cDNA序列。【结果】测序结果表明,两个cDNA均为完整的基因序列,分别命名为GhSAMS(GenBank登录号:EF643509),GhNLP(GenBank登录号:EF643508)。RT-PCR分析表明:开花后4d,GhSAMS、GhNLP在陆地棉李氏野生型li1li1纤维中的表达量低于无纤维突变Li1li1。Southern杂交结果表明两个基因在陆地棉基因组中都存在少数拷贝。利用本实验室陆地棉遗传标准系TM-1和海岛棉海7124培育的140个BC1作图群体,将GhSAMS和GhNLP分别定位在染色体14(D2)和19(D5)上。【结论】克隆了两个棉纤维伸长发育相关基因GhSAMS和GhNLP,推测其高表达阻止纤维伸长生长,为进一步分析功能和用于分子育种打下基础。

[Objective] The objective of this study was to clone new genes related with fiber development in upland cotton. [Method] Genechips were performed with wild line li1li1 and the Ligon lintless mutant line Li1li1 segregated from the self-crossing progenies of the Ligon lintless mutant line Li1 to isolated genes preferentially expressed during elongating for providing the mechanism of cotton fiber rapid elongation. Two cDNA clones differently expressed were separated from cotton fiber library of elite quality material 7235 during fiber elongation and the second wall synthesis by genechips with probes of the 4 DPA ovule-fiber compound from the wild line lilliI and the Ligon lintless mutant line Li1li1. [Result] RT-PCR analysis indicated that the expression quantity of two genes which named GhSAMS （GenBank accession： EF643509） and GhNLP （GenBank accession： EF643508） were less in the wild line lilliI than that in the Ligon lintless mutant line Lillil at 4 DPA. The result of Southern blotting indicated that there are a few copies of both genes in the genome of upland cotton. The authors used the BC1 mapping population derived from the hybridization between the upland cultivar TM-1 and the island cultivar Hai7124, further TM-1 as recurrent parent. GhSAMS and GhNLP were localized on the chromosome D2 and D5, respectively. [Conclusion] Two genes related with fiber development in upland cotton were cloned and characterizated with trancription level, genomic copies and genetic location. Future studies including analyses of these proteins function may shed light on the puzzles about the mechanism of cell elongation and excellent quality formation for cotton fibers.