• 论文 •

### 毛白杨干细胞决定基因 Wuschel 的克隆及其单核苷酸多态性分析

1. （1．北京林业大学林木花卉遗传育种教育部重点实验室　北京100083；2．山东省国营冠县苗圃　冠县252525；3．美国北卡罗莱纳州立大学林学系　北卡罗莱纳州 NC27695-8203）
• 收稿日期:2008-10-08 修回日期:1900-01-01 出版日期:2009-01-25 发布日期:2009-01-25

### Isolation and Single Nucleotide Polymorphisms Analysis of Stem Cell Organizer Gene Wuschel in Populus tomentosa

Yang Xiaohui1,Zhang Youhui2,Zhang Zhiyi1,Li Bailian1,3,Zhang Deqiang1

1. (1. Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education Beijing Forestry University Beijing 100083; 2. Guanxian County Tree Nursery of Shandong Province Guanxian 252525; 3. Department of Forestry, North Carolina State University North Carolina State27695-8203)
• Received:2008-10-08 Revised:1900-01-01 Online:2009-01-25 Published:2009-01-25

Abstract:

Abstract: The Wuschel (Wus) encoding a homeodomain protein which presumably acts as a transcriptional factor plays a key role in maintaining a pool of pluripotent stem cells. In this study, 2 putative sequences of Wus were identified in the whole genome of Populus by underlying the electronic cloning technique, based on the Populus genome sequence using Arabidopsis Wus gene sequence information. Two cDNA clones encoding Wus were isolated from the cDNA prepared from cambium of Populus tomentosa by the gene specific RT-PCR amplification. The two cDNAs were 922 bp and 956 bp in length with corresponding open reading frames (ORFs) which are capable of encoding the protein of 258 and 264 amino acids (aa), respectively. The deduced aa sequence of them shared 76.0% and 74.9% identity with functional domain of A.thaliana Wus, respectively. They were, therefore, named as PtWus-1 and PtWus-2. The genomic sequences of PtWus-1 and PtWus-2 in 36 individuals were aligned, compared and analyzed using the software MEGA3.1 and DnaSP4.0. A total of 58 and 51 single nucleotide polymorphisms (SNPs) were detected and the diversity of them was 1/27 bp and 1/30 bp, respectively. As for PtWus-1, 24 of 58 were common SNPs and 34 were rare SNPs. There were 43 transitions and 15 transversions of mutation types. In total, 21 SNPs were detected in the coding regions of PtWus-1, of which 16 were silent mutations and 4 were missense mutations and 1 was nonsense mutation. In PtWus-2, 28 were common SNPs and 23 were rare SNPs, of which 36 were transitions and 15 transversions of mutation types. In total, 26 SNPs were detected in coding regions of PtWus-2, in which the numbers of silent mutations and missense mutations were 13. The linkage disequilibrium of SNPs in the PtWus-1 and PtWus-2 was detected and the result showed that LD declined rapidly within the gene regions of PtWus-1 and PtWus-2. It suggested that in Populus genome wide LD mapping may not be feasible and not be necessary, but candidate gene based LD mapping could be particularly useful in breeding programs of forest trees. The results, therefore, provided the important foundation for association genetics of Wus genes and gene assisted breeding of new germplasms with desirable wood fiber traits in P. tomentosa.