A Systematic Investigation of the South African Holoparasitic Genus Hyobanche L. (Orobanchaceae)

0089640 Wolfe寄生植物，即那些失去了所有光合能力，并通过吸器（通常是根）连接从附近其他植物吸收营养的植物，在被子植物的几个谱系中是已知的。Hyobanche（列当科）就是这样一个类群，一个小属，大约有八个物种，原产于南部非洲，被认为与光合植物Harveya有关。有相当大的混乱有关的物种界定，丰度，寄主协会，授粉的Hyobanche，这还没有在该领域的任何详细研究。俄亥俄州州立大学的安德里亚·沃尔夫博士正在研究这组植物的系统学、进化和生物学，通过野外收集和观察，结合形态学和DNA测序的实验室工作，获得新的特征，用于系统发育和种群遗传分析。由于该属很小，而且分布范围局限于一个狭窄的地理区域，因此计划从所有物种的种群中对许多个体进行彻底的取样。核和叶绿体基因标记，预计将提供足够的字符强大的物种系统发育的决议，结合形态特征。该属的分类学专著预计作为调查的一个产品，其中将包括详细的地理分布，以帮助保护工作。 该项目的一个有价值的组成部分是叶绿体光合基因rbcL的DNA序列和侧翼区域的详细分子研究，初步数据表明，在这些植物中突变成一个无功能的“假基因”。Hyobanche提供了一个很好的系统，检查在系统发育的背景下，假基因形成的模式和速度后，光合作用的损失。

0089640Wolfe Parasitic plants, ones which have lost all photosynthetic ability and exist by absorbing nutrients through haustorial (usually root) connections from other nearby plants, are known in several lineages of angiosperms. Hyobanche (in the family Orobanchaceae) is one such group, a small genus of eight or so species native to southern Africa, and thought to be related to the photosynthetic genus Harveya. There is considerable confusion regarding species delimitation, abundance, host associations, and pollination for Hyobanche, which has not been studied in the field in any detail. Dr. Andrea Wolfe of Ohio State University is studying the systematics, evolution, and biology of this group of plants, by combining field collecting and observation with laboratory work on morphology and DNA sequencing to acquire new characters for phylogenetic and population-genetic analyses. Because the genus is small and is restricted in distribution to a narrow geographic region, a thorough sampling of many individuals from populations of all the species is planned. Nuclear and chloroplast gene markers are expected to provide sufficient characters for robust phylogenetic resolution of the species, in combination with morphological features. A taxonomic monograph of the genus is projected as one product of the investigation, which will include detailed geographical distributions to aid in conservation efforts. A valuable component of the project is a detailed molecular investigation of the DNA sequences and flanking regions for the chloroplast photosynthetic gene rbcL, which preliminary data suggest to be mutated into a nonfunctional "pseudogene" in these plants. Hyobanche offers an excellent system for examining in a phylogenetic context the pattern and rate of pseudogene formation following the loss of photosynthesis.