Genetic mapping of EST-derived microsatellites from the diploid Gossypium arboreum in allotetraploid cotton
Genetic mapping of EST-derived microsatellites from the diploid Gossypium arboreum in allotetraploid cotton
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DOI：
10.1007/s00438-004-1059-8
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发表时间：
2004-10-01
影响因子：
3.1
通讯作者：
Zhang, TZ
中科院分区：
文献类型：
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作者：
Han, ZG;Guo, WZ;Zhang, TZ
为增加可用于构建遗传图谱的微卫星数量，并促进利用功能基因组学阐明棉花纤维发育和育种，我们从A基因组物种亚洲棉纤维伸长过程中转录的表达序列标签（EST）中采集微卫星序列，以评估它们在四倍体棉花At和Dt亚基因组中的出现频率、多态性水平和分布。在开花后7 - 10天（dpa）来自亚洲棉纤维的EST中，发现931个EST含有简单序列重复（SSR）；开发了544对（58.4%）EST - SSR引物，其中468对（86%）从异源四倍体棉花（陆地棉品种TM - 1和海岛棉品种海7124）中扩增出PCR产物。然而，在我们的种间BC1作图群体[（TM - 1×海7124）×TM - 1]中，发现只有99对（18.2%）具有多态性且发生分离。在这些扩增且有信息的EST - SSR中，六核苷酸和三核苷酸重复基序最为常见，分别占总数的40.1%和30%。用这99个EST - SSR检测到的111个位点被整合到我们包含511个SSR位点的骨干图谱中。EST - SSR的分布似乎是非随机的，因为根据连锁试验，72个位点锚定在异源四倍体棉花的At亚基因组，37个位点锚定在Dt亚基因组。有趣的是，在扩增出的10对重复位点中，有7对被定位到相应的同源连锁群和/或染色体上。BLASTX分析显示，99个EST中有69个与已知基因有显著相似性。一些对纤维发育重要的基因，如蔗糖合酶，被定位到相应的染色体上。这些EST - SSR提供了结构和功能基因组信息，将有助于理解棉花纤维发育。
To increase the numbers of microsatellites available for use in constructing a genetic map, and facilitate the use of functional genomics to elucidate fiber development and breeding in cotton, we sampled microsatellite sequences from expressed sequence tags (ESTs) transcribed during fiber elongation in the A-genome species Gossypium arboreum to evaluate their frequency of occurrence, level of polymorphism and distribution in the At and Dt subgenomes of tetraploid cotton. From among ESTs derived from G. arboreum fibers at 7-10 days post anthesis (dpa), 931 ESTs were found to contain simple sequence repeats (SSRs); 544 (58.4%) EST-SSR primer pairs were developed, and 468 (86%) amplified PCR products from allotetraploid cotton (G. hirsutum cv. TM-1 and G. barbadense cv. Hai7124). However, only 99 (18.2%) of these were found to be polymorphic and segregating in our interspecific BC1 mapping population [(TM-1xHai7124)xTM-1]. In these amplified and informative EST-SSRs, hexa- and tri-nucleotide repeat motifs were the most frequent, representing 40.1 and 30%, respectively, of the total. A total of 111 loci detected with these 99 EST-SSRs were integrated into our backbone map including 511 SSR loci. The distribution of the EST-SSRs appeared to be non-random, since 72 loci were anchored to the At and 37 to the Dt subgenome of allotetraploid cotton based on linkage tests. Interestingly, out of the 10 pairs of duplicate loci amplified, seven were mapped to the corresponding homeologous linkage groups and/or chromosomes. BLASTX analysis revealed that 69 of the 99 ESTs showed significant similarities to known genes. Some genes important for fiber development, such as sucrose synthase, were mapped to corresponding chromosomes. These EST-SSRs provide structural and functional genomic information that will be useful for understanding cotton fiber development.