5种楠木木材DNA的提取与条形码鉴定

DNA Extraction and DNA Barcoding Identification of 5 Wood Species of Phoebe spp. and Machilus spp.

  • 摘要: 以楠属的闽楠、桢楠、紫楠和润楠属的建润楠、刨花润楠为研究对象,分别采用Qiagen试剂盒法、CTAB法和SDS-CTAB法提取木材总DNA,对比不同DNA提取方法的提取效果,探索适合楠木木材DNA提取的方法,尝试用DNA条形码的手段识别几种木材。结果表明:3种方法均可提取出质量较好的新鲜木材的DNA。其中,试剂盒提取的DNA有少量蛋白残留,CTAB法和SDS-CTAB法提取的DNA总体质量较好,有少量RNA存在,但二者提取效果差异不显著。将楠木木材分别经过30、70 ℃和103 ℃干燥后进行DNA提取,发现干燥后的DNA提取量明显下降,其中103 ℃干燥后仅提取出微量DNA,但仍可以满足PCR扩增的需求。综合来看,CTAB法是楠木木材DNA提取的最优方法。在此基础上,分别对5个树种matKtrnL-trnFtrnL-intron和rpoB的4段DNA条形码序列进行PCR扩增,并对PCR产物进行测序和序列比对分析。4段DNA条形码均不能完全区分5个树种。其中,测序所得5个树种的trnL-intron序列共有5个多态性位点,根据其差异可将楠属和润楠属区分开来,建润楠和刨花润楠也能区分开,但是楠属的3个树种之间不能区分。5个树种的matK序列共有3个多态性位点,可将楠属和润楠属区分,建润楠和刨花润楠也能区分开,但是楠属的3个树种之间不能区分。rpoBtrnL-trnF两段序列的比对结果都显示有2个多态性位点,可以将2个属区分开来,属内种间难以区分。总之,从trnL-intron序列构建的系统发育树来看,几个树种基本可以正确聚类。

     

    Abstract: Five species (Phoebe bournei, Phoebe zhennan, Phoebe sheareri, Machilus oreophila, Machilus pauhoi) were chosen to extract timber DNA by using DNeasy Plant Mini Kit(Qiagen), CTAB method and SDS-CTAB method. Based on the effect of DNA extraction, this study explores the method of DNA extraction from Phoebe wood, and several kinds of wood were identified by DNA barcode. The results show that good quality DNA from fresh wood could be extracted by all the 3 methods. Among them, the DNA extracted from the kit has a small amount of protein residue. The DNA extracted by CTAB method and SDS-CTAB method has overall good quality and a small amount of RNA exists, but the difference in extraction effect is not significant. After the wood was dried at 30 ℃, 70 ℃ and 103 ℃, DNA extraction was carried out. It was found that the DNA extraction amount after drying was significantly decreased. Only traces of wood DNA was extracted after drying at 103 ℃, but still meets the needs of PCR amplification. In summary, CTAB method is the best method for DNA extraction from Phoebe wood. After that, four DNA section of matK, trnL-trnF, trnL-intron and rpoB from 5 species were amplified by PCR, and PCR product were sequenced and aligned. The results showed that 4 DNA barcodes do not completely distinguish the 5 species.There are 5 polymorphism sites on trnL-intron sequence between 5 species. Based on the difference, two different genera could be distinguished. Besides, M. oreophila and M. pauhoi could be distinguished while the other 3 could not be. There are 3 polymorphism sites on matK sequence, based on which M. oreophila and M. pauhoi could be distinguished while the other 3 could not be. There are 2 polymorphism sites on both of rpoB and trnL-trnF sequence which could distinguish just between 2 different genera but not species. From the phylogenetic tree obtained by the NJ method based on trnL-intron sequence, five species can be correctly clustered as a reference for distinguishing these tree species.

     

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