Hintz Maren, Bartholmes Conny, Nutt Pia, Ziermann Janine, Hameister Steffen, Neuffer Barbara, Theissen Günter
Friedrich-Schiller-Universität Jena, Lehrstuhl für Genetik, Philosophenweg 12, D-07743 Jena, Germany.
J Exp Bot. 2006;57(13):3531-42. doi: 10.1093/jxb/erl158. Epub 2006 Oct 3.
Capsella is a small genus within the mustard family (Brassicaceae). Its three species, however, show many evolutionary trends also observed in other Brassicaceae (including Arabidopsis) and far beyond, including transitions from a diploid, self-incompatible, obligatory outcrossing species with comparatively large and attractive flowers but a restricted distribution to a polyploid, self-compatible, predominantly selfing, invasive species with floral reductions. All these evolutionary transitions may have contributed to the fact that Capsella bursa-pastoris (shepherd's purse) has become one of the most widely distributed flowering plants on our planet. In addition, Capsella bursa-pastoris shows a phenomenon that, although rare, could be of great evolutionary importance, specifically the occurrence of a homeotic variety found in relatively stable populations in the wild. Several lines of evidence suggest that homeotic changes played a considerable role in floral evolution, but how floral homeotic varieties are established in natural populations has remained a highly controversial topic among evolutionary biologists. Due to its close relationship with the model plant Arabidopsis thaliana, numerous experimental tools are available for studying the genus Capsella, and further tools are currently being developed. Hence, Capsella provides great opportunities to investigate the evolution of flower development from molecular developmental genetics to field ecology and biogeography, and from morphological refinements to major structural transitions.
荠菜属十字花科中的一个小属。然而，它的三个物种呈现出许多在其他十字花科植物（包括拟南芥）中也能观察到的进化趋势，甚至远不止于此，包括从一种具有相对较大且吸引人的花朵、分布受限的二倍体、自交不亲和、 obligatory outcrossing物种，过渡到一种具有花部退化现象的多倍体、自交亲和、主要自花授粉的入侵物种。所有这些进化转变可能促成了荠菜成为地球上分布最广泛的开花植物之一。此外，荠菜还表现出一种现象，尽管罕见，但可能具有重大的进化意义，特别是在野外相对稳定的种群中发现了一种同源异型变种。几条证据线索表明同源异型变化在花的进化中起到了相当大的作用，但花的同源异型变种在自然种群中是如何形成的，在进化生物学家中仍然是一个极具争议的话题。由于它与模式植物拟南芥关系密切，有许多实验工具可用于研究荠菜属，目前还在开发更多工具。因此，荠菜为研究花发育的进化提供了绝佳机会，涵盖从分子发育遗传学、野外生态学和生物地理学，到形态细化和主要结构转变等多个方面。
