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

全球内寄生虫科 Apodanthaceae（葫芦目）：其自然历史、生物地理学、分类学和质体基因组

• 批准号: 235565135
• 负责人: Professorin Dr. Susanne Sabine Renner
• 金额: --
• 依托单位: Department of Biology
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/235565135?language=en
• 关键词: worldwide; endoparasite; family; Apodanthaceae; Cucurbitales

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.

在开花植物中，寄生发生了11次，其中4次导致内寄生，即寄生虫只从寄主身上出现在花和果实上。寄生虫最显著的适应性是叶子和光合能力的丧失，以及它们与宿主的交流，包括蛋白质和核酸的交换。也许并不令人惊讶的是，大部分病毒植物的水平基因转移来自寄生植物。基因组学研究主要集中在外源寄生虫Cuscuta和Orobanchaceae上，而只研究了一种内源寄生虫（Rafflesia cantleyi, Xi et al., 2012）。目前的研究重点是内寄生的豆科植物（Cucurbitales），这是一个世界范围内的18个物种，花长5毫米，主要寄生在豆科植物上，我们从澳大利亚、津巴布韦和伊朗的田野调查中积累了关于其自然史的数据。对一种澳大利亚和一种非洲物种的部分Illumina/Solexa和454测序的质体进行分析表明，基因损失比在任何已分析的寄生植物中发现的都要多。我们现在计划(i)使用一种新的方法来确定Apodanthaceae的系统发育，（ii）研究其质体基因组与其他寄生虫和自养近亲（主要是黄瓜）相比的分化，以及（iii）寻找水平转移的宿主基因。我们还从11个植物标本馆租借了约450个标本，并将分析物种界限、地理范围和宿主特异性。