Chung S-M, Staub J E, Chen J-F
Vegetable Crops Research Unit, Department of Horticulture, US Department of Agriculture-ARS, University of Wisconsin, 1575 Linden Drive, Madison, WI 53706, USA.
Genome. 2006 Mar;49(3):219-29. doi: 10.1139/g05-101.
To investigate phylogenetic relationships in the genus Cucumis, 9 consensus chloroplast simple sequence repeat (ccSSR) primer pairs (ccSSR3, 9, 11, 13, 14, 17, 20, 21, and 23) were employed for DNA fragment length variation and 5 amplified fragments, ccSSR4, 12, 13, 19, and 20, were sequenced using total DNA from 13 accessions representing 7 African Cucumis species (x = 12), 3 Cucumis melo L. (x = 12) accessions, 2 Cucumis sativus L. (x = 7) accessions, and 1 Cucumis hystrix Chakr. (x = 12) accession. A Citrullus lanatus (Thunb.) Matsum. & Nakai (x = 11) accession was used as an outgroup. While fragment length analysis revealed the existence of 3 major species clusters (i.e., a group of African Cucumis species, a group composed of C. melo accessions, and a group containing C. sativus and C. hystrix species), sequence variation analysis identified 2 major species clusters (i.e., a group of African Cucumis species and a group composed of C. melo, C. sativus, and C. hystrix species). Comparative analysis using nuclear DNA (previous studies) and cpDNA sequence substitution data resulted in the placement of C. melo and C. sativus in different cluster groupings. Thus, both nuclear and cytoplasmic DNA should be employed and compared when a putative progenitor or specimens of an ancestral Cucumis species lineage is investigated. In addition, C. ficifolius (2x) and C. aculeatus (4x) of the African Cucumis species clustered together in this study. This result does not agree with reported isozyme analyses, but does agree with previously characterized chromosome homologies between these 2 species. Although African Cucumis species and C. hystrix do not share a close relationship, genetic affinities between C. sativus and C. hystrix are considerable. Combined evidence from previously published studies and data presented herein lend support to the hypothesis that C. hystrix is either a progenitor species of C. sativus or that they at least share a common ancestral lineage.
为了研究黄瓜属内的系统发育关系，使用了9对叶绿体简单序列重复（ccSSR）共有引物对（ccSSR3、9、11、13、14、17、20、21和23）来分析DNA片段长度变异，并对5个扩增片段（ccSSR4、12、13、19和20）进行测序，这些片段来自13份材料，代表7个非洲黄瓜属物种（x = 12）、3份甜瓜（Cucumis melo L.，x = 12）材料、2份黄瓜（Cucumis sativus L.，x = 7）材料以及1份刺黄瓜（Cucumis hystrix Chakr.，x = 12）材料。以西瓜（Citrullus lanatus (Thunb.) Matsum. & Nakai，x = 11）材料作为外类群。虽然片段长度分析揭示了3个主要的物种簇（即一组非洲黄瓜属物种、一组由甜瓜材料组成的物种以及一组包含黄瓜和刺黄瓜物种的材料），但序列变异分析确定了2个主要的物种簇（即一组非洲黄瓜属物种和一组由甜瓜、黄瓜和刺黄瓜物种组成的材料）。使用核DNA（先前的研究）和叶绿体DNA序列替换数据进行的比较分析，导致甜瓜和黄瓜被置于不同的簇分组中。因此，在研究假定的黄瓜属祖先物种谱系的祖先或标本时，应同时使用和比较核DNA和细胞质DNA。此外，在本研究中，非洲黄瓜属物种中的甜瓜叶黄瓜（C. ficifolius，2x）和刺角瓜（C. aculeatus，4x）聚在一起。这一结果与报道的同工酶分析结果不一致，但与先前确定的这两个物种之间的染色体同源性一致。虽然非洲黄瓜属物种与刺黄瓜没有密切关系，但黄瓜与刺黄瓜之间的遗传亲和力相当大。先前发表的研究和本文提供的数据的综合证据支持了这样的假设，即刺黄瓜要么是黄瓜的祖先物种，要么它们至少共享一个共同的祖先谱系。
