Molecular evidence for natural hybridization between Ligularia nelumbifolia and Cremanthodium stenoglossum (Asteraceae, Senecioneae)
Molecular evidence for natural hybridization between Ligularia nelumbifolia and Cremanthodium stenoglossum (Asteraceae, Senecioneae)
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橐吾和Cremanthodium stenoglossum（菊科、千里光科）自然杂交的分子证据
作者：
Ning Huai;Pan Yuezhi;Gong Xun
向日葵家族中经常发生自然杂交。然而，到目前为止，还没有关于连翘属和克氏属植物的自然杂交的研究报道。在此，我们提出了莲叶植物Ligularia nelhumifolia(Bureau&Franch.)手，-梅兹和Cremanthodium狭窄舌藻Ling&S.W.Liu。测序了4个核DNA区域以验证自然杂交假说，并对3个叶绿体DNA区域进行了测序以确定杂交方向。对调查的DNA数据的分析表明，所有推测的杂交个体都是来自L。Nelumifolia和C.狭义词汇和双向杂交的发生。另外，唐川连翘Ligularia sangchanensis(Franch.)手，-梅兹和毛叶连翘Ligularia via(Maxim.)马特夫。前Rehder和Kobuski显然没有参与杂交。虽然新杂交种分析表明，所有推测的杂交个体都是F1级，但回交TOC的频率很低。在杂交群中可能存在狭义词汇。在这种情况下，杂交种可能成为促进L之间基因流动的桥梁。Nelumifolia和C.对于这些没有无性繁殖的杂交个体，不太可能发生杂交物种形成。鉴于Ligularia和Cremanthodium之间的系统发育关系没有得到很好的解决，L.Nelumifolia和C.狭义词汇可能为这两个属的重新界定和重新界定提供新的见解。
Natural hybridization occurred frequently in the sunflower family. To date, however, no study on natural hybridization involving inLigulariaandCremanthodiumhas been reported. Here, we presented the molecular evidence for natural hybridization betweenLigularia nelumbifolia(Bureau & Franch.) Hand.-Mazz. andCremanthodium stenoglossumLing & S.W.Liu. Four nuclear DNA regions were sequenced to test the natural hybridization hypothesis, and three chloroplast DNA regions were sequenced to determine the direction of hybridization. Analyses of the investigated DNA data suggested that all of the putative hybrid individuals were derived from hybridization betweenL. nelumbifoliaandC. stenoglossumand that bidirectional hybridization occurred. Moreover, sympatricLigularia tsangchanensis(Franch.) Hand.-Mazz. andLigularia virgaurea(Maxim.) Mattf. ex Rehder & Kobuski were not apparently involved in the hybridization. Although NewHybrids analysis showed that all the putative hybrid individuals were F1class, a low frequency of backcrossing toC. stenoglossummight exist in the hybrid swarm. In such a case, hybrids might serve as a bridge facilitating gene flow betweenL. nelumbifoliaandC. stenoglossum, and hybrid speciation is unlikely to happen for these hybrid individuals without asexual reproduction. Given the poorly resolved phylogenetic relationship betweenLigulariaandCremanthodium, the occurrence of natural hybridization betweenL. nelumbifoliaandC. stenoglossummight provide new insights into the recircumscription and redelimitation of these two genera.