基于分子序列信息的姜黄属植物系统进化研究

The genus Curcuma L. of the family Zingiberaceae consists of about 70 species in the world, mainly distributed in south and south-east Asian, for example, China, India, Thailand, Myanmar, Indonesia, Malaysia, with some species extending to Australia and the South Pacific. In China, there are more than ten species, mostly occurring in its south and southwest. Curcuma is an economically important genus of the Zingiberaceae. Many species of them have been used as spices, medicines, dyes and ornamentals, which mainly contains various chemical constituents and has broad bioactivities such as anti-oxidation activity, anti-tumor and anti-inflammatory. However, the morphological, geographic, genetic and molecular diversification of the genus Curcuma remains poorly known, representing a formidable challenge for botanists. Till now, the phylogenetic relationships between Curcuma species have remained unresolved， and the number of Curcuma species is still in controversy, and the phylogenetic relationships between the key wild species of Curcuma needs to be clarified. The fact that most infrageneric classifications have been based on small numbers of conspicuous morphological characters that often turn out to be homoplastic, and the frequent lack of sufficient morphological diagnosability of Curcuma has meant that the complex group has been considered to be 'unclassifiable'. Thererfore, the main goals of this project are to generate a hypothesis of phylogenetic and evolutionary relationships based on two chloroplast (rpl16 intron+rps16-trnQ) and four nuclear (ITS, GBSSI, LEAFY and G3pdh) regions for the Curcuma species. Another objects is to assess a subgeneric classification and clarify the taxonomic status of Curcuma species. It is of important significance in Curcuma taxonomy, the origin, phylogenetic breeding, the protections and utility of the germ resources.

姜科（Zingiberaceae）姜黄属Curcuma L．全世界约70种，主要分布于东南亚。我国约10余种，主产东南至西南部。它们具有重要的经济价值，可作药用、香料、染料、化妆品和杀虫剂等。迄今为止，国内外学者对姜黄属植物形态学、亲缘地理学、遗传多样性、分子系统学展开了一系列的研究，但是其原始野生类型的种类及数目仍无定论，系统进化的基本框架仍有待建立。此外姜黄属植物普遍存在三倍体，缺乏稳定可靠的分类性状，杂交与多倍化的存在亦使得姜黄属的分类及系统学研究更为困难。因此，姜黄属植物是研究物种形成、分子进化、生物地理学的最佳材料之一，也是研究网状进化、致同进化等问题的首选材料。本项目运用叶绿体基因（rpl16 intron+rps16-trnQ）、核基因ITS和LEAFY、G3pdh、GBSSI序列构建姜黄属植物系统进化的基本框架，完成分类修订，明确物种的分类地位，为属下等级划分提供分子证据。

姜黄属植物具有重要的经济、药用和观赏价值，但该属植物之间缺乏稳定可靠的形态鉴别特征，因此，本研究采用rbcL、trnH-psbA、trnL-F、matK和ITS2等5个DNA条形码片段对姜黄属植物进行物种鉴定。研究结果表明这5个候选片段的扩增成功率均较高，最高的是rbcL和trnH-psbA（均为100%），最低的ITS2片段成功率也达到了82.6%；5个候选片段的种内种间差异较小，以ITS2的种内种间差异最大。基于BLASTClust和NJ树法检验姜黄属植物物种鉴定效率，其中ITS2片段的鉴定效率最高，为46.7%。虽然利用DNA条形码片段对姜黄属植物特别是姜黄亚属的物种鉴定效率较低，但可以鉴定出一些新种。伍德姜黄Curcuma woodii N. H. Xia & Juan Chen就是利用DNA条形码序列识别的一个新种之一，它具有特有的叶绿体和核基因片段差异位点，这些差异位点足以将其与其他物种区别开来。. 利用ITS2片段构建的姜黄属植物系统发育树表明姜黄属植物可以划分为两支，一支包括大部分姜黄亚属的植物，另一支包括大部分C. subg. Ecomata的物种，支持姜黄属这两个亚属的划分；另外Hichenia glauca、Stahlianthus involucratus、Smithatris myanmarensis、Smithatris supraneanae与姜黄属植物的序列相似度高，显示它们之间的亲缘关系非常近，且与姜黄属植物形成复系类群。鉴于这些近缘属植物及姜黄属植物染色体倍性的差异性及形态特征的较大差异性，进一步说明它们亲本构成及形态特征进化的复杂性。. 姜黄属植物的染色体结果显示，中国姜黄属植物多属于三倍体，且中国姜黄属植物的三倍体和四倍体都属于姜黄亚属（C. subg. Curcuma），二倍体属于C. subg. Ecomata。广布的三倍体植物是如何形成及传播一直是难解之谜。同时，C. subg. Ecomata并未参与姜黄亚属的多倍体成种，而是具有自己独立的进化路线。. 将中国姜黄属植物修订为19种，归并4个异名，恢复1种名，发现3个新种及3个新纪录种，澄清1个种在中国没有分布、1个种在中国仅在华南植物园有栽培、1个种在中国可能有分布，2个不合格发表名称，将一个种名转移至凹唇姜属Boesenbergia。