Hatt Sebastian A, Grace Olwen M, Zuntini Alexandre R, Cameron Duncan D, Thorogood Chris J
Royal Botanic Gardens, Kew, London TW9 3AE, UK.
Earth and Environmental Sciences, University of Manchester, Manchester M13 9PL, UK.
Ann Bot. 2025 Jul 14;135(6):1135-1146. doi: 10.1093/aob/mcae180.
The host specificity of a parasite underpins its ecology, distribution, invasive potential and adaptability, yet for most parasitic plants the host ranges are poorly understood. We examine host-parasite relationships across lineages to infer how host specificity might have influenced the evolution of parasitism in plants.
Host preference data for all plant holoparasite species were collected manually from literature and herbarium specimens, then analysed to investigate and visualize host diversity and specificity.
We reveal a disproportionality in host preference across host lineages: the Asteraceae contain 10 % of angiosperm diversity but are infected by 31 % of parasite species; meanwhile, monocots comprise 23 % of angiosperm diversity but are infected by only 3.2 % of parasite species of parasite species. Furthermore, we observe striking convergence in host preference: Asteraceae, Euphorbiaceae and Fabaceae are infected by six, five and four independent parasite lineages, respectively. We also demonstrate considerable variation in the degree of host specificity among closely related parasite species; a result that does not reflect the expectation of holoparasites (especially endoparasites) as host specialists.
The marked pattern of convergence in preference across disparate lineages points to a common pathway in the evolution of parasitism of eudicots in preference to monocots, which might, in turn, have been driven by a divergence in host root and vascular architecture. The unexpected variation in host specificity among closely related species suggests that even apparent generalists might contain cryptic host-specific taxa. This highlights the value of host preference as an additional consideration in parasitic plant taxonomy. Together, our data point to a complex interplay between ecological and physiological factors driving the evolution of host-parasite interactions. Moreover, they emphasize how little is known about the ecology of most holoparasitic plants, a group of organisms that are especially vulnerable at a time of unprecedented biodiversity loss and extinction.
寄生虫的宿主特异性支撑着其生态、分布、入侵潜力和适应性，然而对于大多数寄生植物而言，其宿主范围却知之甚少。我们研究了不同谱系间的宿主 - 寄生虫关系，以推断宿主特异性可能如何影响植物寄生现象的进化。
从文献和植物标本馆标本中手动收集所有植物全寄生物种的宿主偏好数据，然后进行分析以研究和可视化宿主多样性及特异性。
我们揭示了宿主谱系间宿主偏好的不均衡性：菊科植物占被子植物多样性的10%，却被31%的寄生植物物种感染；与此同时，单子叶植物占被子植物多样性的23%，但仅被3.2%的寄生植物物种感染。此外，我们观察到宿主偏好存在显著趋同现象：菊科、大戟科和豆科分别被六个、五个和四个独立的寄生植物谱系感染。我们还证明了亲缘关系相近的寄生植物物种在宿主特异性程度上存在相当大的差异；这一结果并不符合全寄生植物（尤其是内寄生植物）作为宿主专性物种的预期。
不同谱系间偏好的显著趋同模式表明，真双子叶植物寄生现象进化存在一条偏好单子叶植物的共同途径，这反过来可能是由宿主根系和维管结构的差异驱动的。亲缘关系相近的物种间宿主特异性的意外差异表明，即使是看似泛化的物种可能也包含隐秘的宿主特异性分类群。这凸显了宿主偏好作为寄生植物分类学中一个额外考量因素的价值。总之，我们的数据表明生态和生理因素之间存在复杂的相互作用，驱动着宿主 - 寄生虫相互作用的进化。此外，这些数据强调了我们对大多数全寄生植物生态学的了解是多么匮乏，而在生物多样性前所未有的丧失和灭绝时期，这一类生物尤其脆弱。
