Two genes （GhC4H1 and GhC4H2） that encode putative cotton cinnamate 4-hydroxylases that catalyze the second step in the phenylpropanoid pathway were isolated from developing cotton fibers. GhC4H1 and GhC4H2 each contain open reading frames of 1 518 base pairs （bp） in length and both encode proteins consisting of 505 amino acid residues. They are 90.89% identical to each other at the amino acid sequence level and belong to class I of plant C4Hs. GhC4H1 and GhC4H2 genomic DNA are 2 247 and 2 161 bp long, respectively, and contain two introns located at conserved positions relative to the coding sequence. GhC4HI and GhC4H2 promoters were isolated and found to contain many cis-elements （boxes P, L and AC-1 element） previously identified in the promoters of other phenylpropanoid pathway genes. Histochemical staining showed GUS expression driven by the GhC4H1 and GhC4H2 promoters in ovules and fibers tissues. GhC4H1 and GhC4H2 were also widely expressed in other cotton tissues. GhC4H2 expression reached its highest level during the elongation stage of fiber development, whereas GhC4H1 expression increased during the secondary wall development period in cotton fibers. Our results contribute to a better understanding of the biochemical role of GhC4H1 and GhC4H2 in cotton fiber development.
【目的】利用已有的棉花种间分子遗传连锁图谱信息,在陆地棉和海岛棉之间筛选具有共显性差异的SSR标记,并用这些标记构建新疆棉花海陆杂交BC1群体的遗传图谱。【方法】使用Bio Mercator软件比较分析10张不同群体(亲本不同)构建的遗传图谱,选择至少已在3个不同的群体中被定位,且在不同的图谱中被定位在同一条染色体上的SSR标记作为候选标记。将候选标记在多个陆地棉和海岛棉品种间进行多态性检测后,利用具有共显性差异的标记对陆海杂交BC1群体进行基因型分析,使用Joinmap软件构建遗传连锁图谱。【结果】从5 501对SSR引物中初选了763对,经检验具有多态性的引物403对,多态性比例为53%。选用其中77对引物在5个陆地棉和5个海岛棉之间进行扩增,有21对SSR引物在所有的亲本之间均具有多态性。77对SSR引物对BC1群体[(Gh line 565×Gb新海25号)×Gh line 565]的94株材料基因型进行检测,构建了一张由53个SSR标记,16个连锁群组成,全长为643.4 c M的遗传连锁图谱。【结论】利用77个SSR标记构建了棉花种间遗传图谱。为新疆棉花遗传图谱的绘制提供较准确的锚定标记和有育种潜力的共显性差异标记。
