Natural hybridization and introgression in sympatric Ligularia species(Asteraceae,Senecioneae)  

作　　者：Jiao-Jun YU Chiaki KURODA Xun GONG 

机构地区：[1]Key Laboratory of Economic Plants and Biotechnology,Kunming Institute of Botany,Chinese Academy of Sciences,Kunming 650201,China [2]Graduate School of the Chinese Academy of Sciences,Beijing 100049,China [3]Department of Chemistry,Rikkyo University,Tokyo 171-8501,Japan

出　　处：《Journal of Systematics and Evolution》2011年第5期438-448,共11页植物分类学报（英文版）

基　　金：supported by grants from the National Natural Science Foundation of China (Grant No. 30870242) ;the National Basic Research Program of China (973 Program:2007CB411600)

摘　　要：The difficulty in clarifying species of genus Ligularia Cass.has been attributed to rapid and continuous allopatric speciation in small and isolated populations,combined with interspecific diploid hybridization in the Qinghai-Tibetan Plateau and adjacent areas.However,no concrete example has been reported to prove this hypothesis.We studied a natural mixed population of six species of Ligularia in which some individuals were morphologically intermediate between L.subspicata and L.nelumbifolia.Based on DNA sequences（trnC-F,trnL-rpL32,trnQ5 rps16,trnK-rps16,and internal transcribed spacer） and inter-simple sequence repeat data,we concluded that putative hybrids are primarily products of hybridization between L.nelumbifolia and L.subspicata.The other four species or additional,unknown species may also be involved in hybridization.This hybridization is bidirectional but asymmetrical.Hybrid individuals were mostly the first generation,but F2 and later-generation hybrids were also present.Moreover,the backcrossed individuals detected indicate that natural gene flow occurs among at least three Ligularia species.Hybrids may become stabilized to form new species or may function as intermediates in evolutionary diversification.The difficulty in clarifying species of genus Ligularia Cass.has been attributed to rapid and continuous allopatric speciation in small and isolated populations,combined with interspecific diploid hybridization in the Qinghai-Tibetan Plateau and adjacent areas.However,no concrete example has been reported to prove this hypothesis.We studied a natural mixed population of six species of Ligularia in which some individuals were morphologically intermediate between L.subspicata and L.nelumbifolia.Based on DNA sequences（trnC-F,trnL-rpL32,trnQ5 rps16,trnK-rps16,and internal transcribed spacer） and inter-simple sequence repeat data,we concluded that putative hybrids are primarily products of hybridization between L.nelumbifolia and L.subspicata.The other four species or additional,unknown species may also be involved in hybridization.This hybridization is bidirectional but asymmetrical.Hybrid individuals were mostly the first generation,but F2 and later-generation hybrids were also present.Moreover,the backcrossed individuals detected indicate that natural gene flow occurs among at least three Ligularia species.Hybrids may become stabilized to form new species or may function as intermediates in evolutionary diversification.

关 键 词：chloroplast fragments ISSR markers LIGULARIA natural hybridization nuclear ribosomal ITS. 

分 类 号：Q949.783.5[生物学—植物学] S835[农业科学—畜牧学]