期 刊 ：植物遗传资源学报 2014年 15卷 5期
关键词：节瓜；葫芦科作物；种质资源；rDNA-ITS；序列分析；系统进化；
Keywords:Chieh-qua, Cucurbitaceous crops, Germplasm resources, rDNA-ITS, Sequence analysis, Phyletic evolution,
摘 要 ：PCR扩增收集的56份节瓜种质资源及7份相关瓜类种质资源的rDNA-ITS序列，测序后结合GenBank下载的部分葫芦科作物ITS序列，利用生物信息学软件分析序列长度、变异位点、G C%含量、遗传分歧、同源性百分比差异、系统位置与进化关系。获得节瓜及近缘葫芦科作物种质资源ITS完整序列，其中节瓜种质资源ITS基本序列全长612～617 bp，G C含量59.97%-61.07%（ITS1：218～219 bp，G C%含量59.17-60.09%，ITS2：230～232bp，G C%含量61.30%～64.22%，5.8S：163bp，G C%含量58.28%～59.51%）。序列比对表明，节瓜种质资源间共96个变异位点(ITS1：47，ITS2：42，5.8S：7)，一些变异位点有明显的种性特征，可作为特异DNA指纹鉴别位点。基于ITS序列差异，56份节瓜种质资源聚为5类，其中12-2-3材料为单独一分支，黑毛节瓜H2251为第二分支，H5FA为第三分支，剩余节瓜材料与冬瓜材料聚分为第四、五分支。节瓜材料12-2-3与其它材料遗传分歧最大，为3.3～4.6，可作为节瓜杂交育种的亲本。节瓜的系统位置排列在Indomelothria blumei (GU799496)与Dactyliandra welwitschii (HQ201973)之间，与Indomelothria blumei亲缘关系最近；Mrbayes软件分析表明，Zehneria thwaitesii (AM981145)、Ctenolepis cerasiformis (AM981142)、Cucumis melo(AM36377)、Dactyliandra welwitschii (HQ201973)、Trochomeria macrocarpa (AM981141)最原始，系统进化顺序为：甜瓜(Cucumis melo, AM36377)→南瓜、栝楼、苦瓜、丝瓜、西瓜、蒲瓜→冬瓜、节瓜→黄瓜。本研究通过分析节瓜及近缘葫芦科作物种质资源ITS序列，为其系统位置、进化关系、DNA指纹鉴别、育种亲本选择及比较组学分析等提供分子生物学依据。
Abstract:Fifty-six Chieh-qua and 7 other cucurbits germplasm resources were collected from South China, subsequently rDNA-ITS amplication and sequencing were performed. With regard to them and ITS sequences of several cucurbitaceous plant downloaded from GenBank, the lengths, variable sites, G C% contents, genetic divergences, homologies, phylogenetics and system position were analyzed by bioinformatic softwares. ITS complete sequences of Chieh-qua and its affinis cucurbitaceae germplasm resources were obtained. The full-length of chieh-qua ITS was 608bp, G C% content were 59.33%( ITS1: 221 bp, G C% content: 60.18%, ITS2: 231bp, G C% content: 63.64%, 5.8S: 157bp, G C% content: 57.96%). The sequence alignment results showed that there were 94 variable sites（ITS1: 47, ITS2: 40, 5.8S: 7）among chieh-qua germplasm resources, some of them had significant species-specific characteristics and could be used as DNA fingerprint markers of Chieh-qua germplasm resources. 56 chieh-qua germplasm materials were clustered into 3 groups based on ITS sequences variance, 12-2-3 was ranked into the first branch, “Heimaojie H2251” was classified into the second branch, and the rest chieh-qua materials and wax gourd were grouped into the third group containing 4 subgroups. Compared with the other cultivated species, the variation of chieh-qua material 12-2-3 was the biggest, the genetic divergence ranged from 4.5 to 5.6. The system position of Chieh-qua was between Indomelothria blumei (GU799496) and Dactyliandra welwitschii (HQ201973), and had the closest relationship with Indomelothria blumei. Based on Mrbayes software analysis, Zehneria thwaitesii(AM981145), Ctenolepis cerasiformis (AM981142), Cucumis melo (AM36377), Dactyliandra welwitschii (HQ20 1973), Trochomeria macrocarpa (AM981141) were the most primordial species, the system evolution order was Cucumis melo(AM36377) → Cucurbita moschata, Trichosanthes yunnanensis, Momordica charantia, Luffa aegyptiaca, Citrullus lanatus (FJ915098), Lagenaria siceraria → Benincasa hispida, Benincasa hispida var. chieh-qua How → Cucumis sativus. The phylogeny of Chieh-qua and its affinis cucurbitaceae germplasm resources was investigated by using ITS sequences and it would provide useful information for their breeding, germplasm DNA fingerprint identification, classification and evolution and comparative analysis, etc.