The worldwide endoparasite family Apodanthaceae (Cucurbitales): Its natural history, biogeography, taxonomy, and plastid genome

在开花植物中，寄生现象已经出现了11次，其中4次导致了内寄生，其中寄生虫只从宿主出现到花和果实。寄生虫最引人注目的适应是叶片和光合能力的丧失，以及它们与宿主的交流，包括蛋白质和核酸的交换。也许并不令人惊讶，大多数情况下，水平基因转移Viridiplantae来自寄生植物。基因组研究集中于体外寄生物菟丝子属（Cuscuta）和列当科（Orobanchaceae），而仅研究了一种体内寄生物（Rafflesia cantleyi，Xi et al.，2012年）。本建议的重点是内寄生Apodanthaceae（葫芦目），一个世界性的18种，主要寄生在豆科植物的花分钟（5毫米长），其自然历史，我们已经积累了数据，从澳大利亚，津巴布韦和伊朗的野外工作。部分分析Illumina/Solexa-和454-测序的一个澳大利亚和一个非洲物种的质体表明更多的基因丢失比任何寄生植物中发现的分析。我们现在计划（i）使用一种新的方法为Apodanthaceae产生一个过时的基因组，（ii）研究其质体基因组与其他寄生虫和自养亲属（主要是黄瓜）相比的分化，以及（iii）寻找水平转移的宿主基因。我们也有贷款C。来自11个标本馆的450个标本，并将分析物种的环境，地理范围和宿主特异性。

In flowering plants, parasitism has arisen some 11 times, four of them leading to endoparasitism in which parasites only emerge from the host to flower and fruit. Parasites´ most striking adaptations are the loss of leaves and photosynthetic capacity, and their communication with the host, including the exchange of proteins and nucleic acids. Perhaps not surprisingly, most cases of horizontal gene transfers in Viridiplantae come from parasitic plants. Genomic studies have focused on the exoparasites Cuscuta and Orobanchaceae, while only one endoparasite has been investigated (Rafflesia cantleyi, Xi et al., 2012). The present proposal focuses on the endoparasitic Apodanthaceae (Cucurbitales), a worldwide group of 18 species with minute (5 mm-long) flowers that mostly parasitize Fabaceae and on whose natural history we have accumulated data from fieldwork in Australia, Zimbabwe, and Iran. Partly analyzed Illumina/Solexa- and 454-sequenced plastomes of one Australian and one African species suggest more gene loss than found in any parasitic plant yet analyzed. We now plan to (i) produce a dated phylogeny for the Apodanthaceae using a novel approach, (ii) study the differentiation of their plastid genome compared to other parasites and autotrophic relatives (mainly Cucumis sativus), and (iii) look for horizontally transferred hosts genes. We also have on loan c. 450 specimens from 11 herbaria and will analyze species circumscriptions, geographic ranges, and host specificity.