基于细胞核ITS序列的变叶海棠起源新证据  

New evidence for hybrid origin of Malus toringoides as inferred fromn rDNA ITS sequences

作　　者：唐建民[1] 周志钦[1,2] 冯婷婷[1] 成明昊[1] 

机构地区：[1]西南大学园艺园林学院,重庆400716 [2]中国农业科学院柑桔研究所,重庆400712

出　　处：《果树学报》2009年第3期265-270,共6页Journal of Fruit Science

基　　金：国家自然科学基金(NSFC30471206);中国农业科学院杰出人才基金

摘　　要：在利用ITS序列初步证明苹果属植物变叶海棠(Malus toringoides Hughes.)杂种起源的基础上,对其3个自然居群(马尔康雅尔珠林场、柯河和下阿坝)47个样品(其中18个新样品)的核糖体DNA的ITS区进行了进一步测序分析。以窄叶海棠(M.angustifolia Michx.)、草原海棠(M.ioensis Britt.)和台湾林檎(M.doumeri Chev.)作为外类群,结合已报道的变叶海棠的ITS序列,对变叶海棠及其假定亲本的种间特异位点和系统进化关系进行了分析,并用软件RDP3beta27对变叶海棠的ITS序列进行了重组检测。结果表明,变叶海棠居群有3种ITS拷贝变异类型:1)与陇东海棠(M.kansuensis Schneid.)相似的ITS拷贝;2)与花叶海棠(M.transitoria Schneid.)相似的ITS拷贝;3)杂合的ITS拷贝。在ITS基因树上3类ITS拷贝分别与2个推测亲本单独聚在一支(自展值分别为100%和92%);杂合的ITS拷贝虽与花叶海棠聚在同一大支(B),但杂合的ITS拷贝在B支内形成具有94%自展值支持的次级分支。重组检测支持杂合ITS拷贝是假定亲本ITS重组进化的产物。上述结果为变叶海棠的杂种起源提供了进一步的分子证据。On the basis of preliminary confirmation of the hybrid origin of Malus toringoides using internal transcribed spacer （ITS） sequence, ITS sequences of nuclear ribosomal DNA of 47 accessions （18 new accessions） collected from three natu ral populations （Maerkang, Xiaaba and Kehe） of M. toringoides were sequenced in the present study. Using M. angustifolia Michx., M. ioensis Britt. and M. doumeri Chev. as outgroups, diagnostic nucleotides between M. kansuens/s and M. transitoria and phylogenetic relationship between M. toringoides and its putative parents were analyzed using the sequences obtained in this study and before. The recombination detection of M. toringoides sequences was also carried out using RDP3beta27 program. The results indicated that 3 different types of ITS sequences from M. toringoides were obtained ,which are identical to M. transitoria sequence or to M. kansuensis sequence, or they are mosaic sequences of M. kansuensis and M. transitoria. On the gene tree, 3 different types of ITS sequences clustered separately with the 2 putative parents of M. toringoides with ·strongly statistical supports. All mosaic ITS sequences from M. toringoides formed a secondary branch within the CladeB with a bootstrap value of 94%. Recombination detection indicated that all mosaic ITS sequences appear to be the evolutionary product of a recombination event between ITS sequences of M. kansuensis and M. transitoria. These results provide a new evidence for the hybrid origin hypothesis ofM. toringoides on the basis of our previous work.

关 键 词：变叶海棠 杂交起源 重组 ITS 

分 类 号：S661.1[农业科学—果树学]