Strong population structure characterizes weediness gene evolution in the invasive grass species Brachypodium distachyon
Strong population structure characterizes weediness gene evolution in the invasive grass species Brachypodium distachyon
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DOI：
10.1111/j.1365-294x.2009.04225.x
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发表时间：
2009-06-01
影响因子：
4.9
通讯作者：
Borer, Elizabeth T.
中科院分区：
文献类型：
--
作者：
Bakker, Erica G.;Montgomery, Brooke;Borer, Elizabeth T.
地中海一年生草已经入侵加州，并取代了大片的原生草原。二穗短柄草（Brachypodium distachyon）是一种新的模式种，具有广泛的基因组资源和接近完整的基因组序列。这项研究表明，入侵加州草原的遗传变异水平低于欧亚大陆的本地范围。入侵区域的特点是高度分化的B种群。这是一个由距离隔离的二穗子，最有可能是由于创始人效应和缺乏异交事件。EXP 6和EXP 10编码的α-扩展蛋白负责快速生长，和AGL 11和AGL 13编码的蛋白质参与营养期调节，似乎是在纯化选择没有证据的地方适应。我们的数据表明，B.二穗草只是最近才从相关的短柄草物种中分化出来，四倍化可能是在几千年前。观察到的低遗传变异EXP 10和AGL 13似乎已经存在于欧亚大陆之前，四倍化，可能是由于强大的选择压力，有利的突变，这是最有可能负责其快速增长和快速完成其生命周期。
Mediterranean annual grasses have invaded California and have replaced vast areas of native grassland. One of these invasive grasses is Brachypodium distachyon, a new model species for the grasses with extensive genomic resources and a nearly completed genome sequence. This study shows that the level of genetic variation in invaded California grasslands is lower compared to the native range in Eurasia. The invaded regions are characterized by highly differentiated populations of B. distachyon isolated by distance, most likely as a result of founder effects and a dearth of outcrossing events. EXP6 and EXP10 encoding alpha-expansins responsible for rapid growth, and AGL11 and AGL13 encoding proteins involved in vegetative phase regulation, appear to be under purifying selection with no evidence for local adaptation. Our data show that B. distachyon has diverged only recently from related Brachypodium species and that tetraploidization might have been as recent as a few thousand years ago. Observed low genetic variation in EXP10 and AGL13 appears to have been present in Eurasia before tetraploidization, potentially as a result of strong selective pressures on advantageous mutations, which are most likely responsible for its fast growth and rapid completion of its life cycle.