More than multiple introductions： Multiple taxa contribute to the genesis of the invasive California＇s wild artichoke thistle  

作　　者：Janet LEAK-GARCIA Jodie S. HOLT Seung-Chul KIM Lisa MU Jose A. MEJIAS Norman C. ELLSTRAND 

机构地区：[1]Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA

出　　处：《Journal of Systematics and Evolution》2013年第3期295-307,共13页植物分类学报（英文版）

基　　金：This work was supported in part by Graduate Assistance in Areas of National Needs (GAANN)Fellowship,United States National Science Foundation Grants，a John Simon Guggenheim Memorial Fellowship awarded to N.C.ELLSTRAND,a grant from the Elvenia J.SLOSSON Endowment Fund awarded to J.S.HOLT,and a UC Dissertation Year Fellowship

摘　　要：The history of some invasive species is so complex that their origins can be difficult to determine. One example of such invasive species is the California invasive known as ＂wild artichoke thistle＂ （Cynara cardunculus var. sylvestris）, found in natural and disturbed ecosystems. Wild artichoke thistle is a Mediterranean native and the progenitor of two domesticated horticultural taxa, artichoke and cardoon. Different hypotheses regarding the origins of California plants have included introductions by 19th century Italian immigrants and the de-domestication （evolutionary reversion to wild-type morphology） of feral （escaped, free-living） cultivars. Using microsatellite markers, we compared the genetic constitutions of 12 artichoke thistle populations in California with possible progenitor populations： 17 Spanish and Italian wild populations and eight different artichoke and cardoon cultivars. Each California population was compared with its putative progenitors using STRUCTURE analysis. Our results suggest that California＇s artichoke thistle populations are polyphyletic. Surprisingly, two-thirds of California＇s populations closely matched populations from the Iberian Peninsula. Three populations matched domesticated artichoke. One population appears to have wild and cultivar hybrid ancestry. Alleles specific to Italian populations were found at low frequencies in some California plants, suggesting that Italian wild plants may have been in California, but have left a trivial genetic legacy. Given that the de-domesticated plants in this study appear to be as invasive as the wild taxon, we conclude with a discussion of the role that ferality and de-domestication may have in plant invasions.The history of some invasive species is so complex that their origins can be difficult to determine. One example of such invasive species is the California invasive known as ＂wild artichoke thistle＂ （Cynara cardunculus var. sylvestris）, found in natural and disturbed ecosystems. Wild artichoke thistle is a Mediterranean native and the progenitor of two domesticated horticultural taxa, artichoke and cardoon. Different hypotheses regarding the origins of California plants have included introductions by 19th century Italian immigrants and the de-domestication （evolutionary reversion to wild-type morphology） of feral （escaped, free-living） cultivars. Using microsatellite markers, we compared the genetic constitutions of 12 artichoke thistle populations in California with possible progenitor populations： 17 Spanish and Italian wild populations and eight different artichoke and cardoon cultivars. Each California population was compared with its putative progenitors using STRUCTURE analysis. Our results suggest that California＇s artichoke thistle populations are polyphyletic. Surprisingly, two-thirds of California＇s populations closely matched populations from the Iberian Peninsula. Three populations matched domesticated artichoke. One population appears to have wild and cultivar hybrid ancestry. Alleles specific to Italian populations were found at low frequencies in some California plants, suggesting that Italian wild plants may have been in California, but have left a trivial genetic legacy. Given that the de-domesticated plants in this study appear to be as invasive as the wild taxon, we conclude with a discussion of the role that ferality and de-domestication may have in plant invasions.

关 键 词：artichoke thistle Cynara cardunculus de-domestication ferality invasive species multiple origins. 

分 类 号：S541.9[农业科学—作物学] Q16[生物学—普通生物学]