Natural Hybrids and Gene Flow between Upland and Lowland Switchgrass
Natural Hybrids and Gene Flow between Upland and Lowland Switchgrass
复制标题
DOI：
10.2135/cropsci2011.02.0104
复制
发表时间：
2011-11
期刊：
影响因子：
2.3
通讯作者：
Yun-Wei Zhang;J. Zalapa;Andrew R. Jakubowski;D. L. Price;A. Acharya;Yanling Wei;E. Brummer;S. Kaeppler;S. Kaeppler;M. Casler;M. Casler
中科院分区：
文献类型：
--
作者：
Yun-Wei Zhang;J. Zalapa;Andrew R. Jakubowski;D. L. Price;A. Acharya;Yanling Wei;E. Brummer;S. Kaeppler;S. Kaeppler;M. Casler;M. Casler
柳枝稷（Panicum virgatum L.）是一种多年生草本植物，原产于北美高草草原和稀树草原栖息地，广泛适应于美国中部和东部。高地和低地生态型代表柳枝稷内的两个主要分类单元，它们具有不同但重叠的分布。本研究的目的是调查一系列假定的高地和低地种质，以了解可能存在的自然杂交种或杂交衍生物，以及两种生态型之间历史基因流的证据。根据表型的视觉评估，所有植物被分类为高地、低地或中间植物，使用已知高地或低地植物的大型苗圃作为对照。总共对 480 株植物进行了 19 个简单序列重复 (SSR) 标记的调查，并使用 5 个叶绿体 DNA (cpDNA) 片段进行了测序。遗传结构分析揭示了 21 个个体具有类群间杂交起源的有力证据，另外 25 个个体具有类群间杂交起源的中等证据。除两个个体外，所有这些个体都起源于墨西哥湾中部或东部海岸或大西洋沿岸的残余种群，该地区居住着大量的高地和低地生态类型。我们建议墨西哥湾沿岸中部和东部冰川保护区作为柳枝稷的主要起源和多样性中心，而墨西哥湾西部海岸作为次要起源和多样性中心。这种多样性的大部分似乎是沿着主要的冰河后向北迁徙路线之一——大西洋沿岸——保留下来的。
Switchgrass (Panicum virgatum L.) is a perennial grass native to the North American tallgrass prairie and savanna habitats and is broadly adapted to the central and eastern United States. Upland and lowland ecotypes represent the two major taxa within switchgrass, which have distinct but overlapping distributions. The purpose of this study was to survey a broad array of putative upland and lowland accessions for the possible presence of natural hybrids or hybrid derivatives and evidence of historic gene fl ow between the two ecotypes. All plants were classifi ed as upland, lowland, or intermediate based on visual assessment of phenotype, using large nurseries of known upland or lowland plants as controls. A total of 480 plants were surveyed for 19 simple sequence repeat (SSR) markers and sequenced using fi ve chloroplast DNA (cpDNA) segments. Genetic structure analysis revealed 21 individuals with strong evidence for intertaxa hybrid origin and another 25 individuals with moderate evidence for intertaxa hybrid origin. All but two of these individuals originated from remnant populations of the central or eastern Gulf Coast or along the Atlantic Seaboard, a region that is populated with signifi cant quantities of both upland and lowland ecotypes. We propose the central and eastern Gulf Coast glacial refuge as the primary center of origin and diversity for switchgrass, with the western Gulf Coast as the secondary center of origin and diversity. Much of this diversity appears to have been preserved along one of the major northward postglacial migration routes, the Atlantic Seaboard.