Systematics and evolution of parasitic plants

寄生植物的系统学和进化

• 批准号: RGPIN-2017-05304
• 负责人: Costea, Mihai
• 金额: $ 2.04万
• 依托单位: Wilfrid Laurier University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=682839
• 关键词: Systematics; evolution; parasitic; plants

Parasitic plants take water and nutrients from other plants called hosts. Some parasitic plants, referred to as “obligate”, depend entirely on their hosts for survival and negatively affect their growth and development. The proposed research program focuses on the species diversity and evolution of Cuscuta (dodder), a taxonomically challenging group of obligate parasitic plants comprising ~ 200 species distributed worldwide. The taxonomical difficulties of Cuscuta arise in part because the morphological variation among species is minimal and hidden inside the small flowers (~ 3 mm long). In addition, the recently documented hybrid formation of species (reticulate evolution) complicates the reconstruction of evolutionary histories. This parasitic group is particularly important because native dodders are keystone species in their ecosystems. However, Cuscuta is also economically important because some of its species are agricultural and horticultural pests that cause major yield losses in numerous crops. *** The first short-term objective of the proposed research is to unravel species-level evolutionary histories within four unstudied groups of Cuscuta, and to uncover the depth and extent of reticulate evolution in two other groups in which we have previously shown that hybrid speciation occurs. We will use molecular and morphological data to understand how species have evolved, based on which we will also revise their taxonomy. New species are likely to be discovered as a part of this research. *** Cuscuta has a pronounced variation of the chromosome number (polyploidy) and the second short-term aim of this research is to elucidate how the extra sets of chromosomes have been acquired and to identify the role that these changes had in the evolution of dodders. Since reticulate evolution and polyploidy often work in tandem, the chromosome data will provide a more thorough understanding of how hybrid species originated.*** The host range is an essential attribute of any parasitic organism and represents the totality of hosts that the parasite can attack. The third short-term objective of this research program aims to characterize for the first time the host range and its evolution in Cuscuta. The study of the host range has been hindered in Cuscuta because most dodders infest many hosts from numerous botanical families. To solve this problem, we will obtain host data from tens of thousands of herbarium specimens, and use novel analytical approaches employed in animal parasites. *** Overall, this research program is part of the ongoing global efforts to catalog life on Earth and understand its natural history and evolution. From a practical point of view, the results will facilitate a better identification and management of both native and pest Cuscuta species from Canada and the rest of the world. Host range results can be used to model and predict the potential expansion of pest dodders.

寄生植物从其他称为宿主的植物中取水和养分。一些寄生植物，被称为“义务”，完全取决于其生存的宿主，并对其成长和发展产生负面影响。拟议的研究计划的重点是库斯库塔（Dodder）的物种多样性和进化，这是一个具有分类学挑战性的寄生植物，完成了〜200种全球分布的物种。库斯库塔的分类困难部分出现了，部分原因是物种之间的形态变化很小，隐藏在小花（长3毫米）内。此外，最近记录的物种的杂种形成（网状进化）使进化史的重建变得复杂。这个寄生群体尤其重要，因为本地燕魔者是其生态系统中的基石物种。但是，库斯库塔在经济上也很重要，因为它的某些物种是农业和辣根害虫，在许多农作物中造成重大产量损失。 ***拟议的研究的第一个短期目标是在四个未研究的Cuscuta群体中揭示物种水平的进化历史，并发现其他两个我们先前表明混合规格发生的其他组中的网状演化的深度和程度。我们将使用分子和形态学数据来了解物种如何发展，我们还将修改它们的分类法。这项研究的一部分很可能被发现新物种。 ***库斯库塔具有明显的染色体数（多倍体）变化，这项研究的第二个短期目标是阐明如何获得额外的染色体集合，并确定这些变化在Dodders的演变中的作用。由于网状演化和多倍体通常在同时起作用，因此染色体数据将对杂种物种的起源进行更透彻的了解。该研究计划的第三个短期目标旨在首次表征宿主范围及其在库斯库塔的演变。库斯库塔（Cuscuta）对宿主范围的研究受到了阻碍，因为大多数道奇（Dodders）侵扰了来自众多植物家庭的许多宿主。为了解决这个问题，我们将从数以万计的标本室物种中获取宿主数据，并使用在动物寄生虫中采用的新分析方法。 ***总的来说，该研究计划是全球努力对地球上生命并了解其自然历史和进化的持续努力的一部分。从实际的角度来看，结果将有助于对来自加拿大和世界其他地区的本地和害虫物种进行更好的识别和管理。宿主范围的结果可用于建模和预测害虫道夫的潜在扩展。