Rethinking convergence in plant parasitism integrating molecular and population genetic processes

Abstract

The need for photosynthesis has largely shaped the body plan, physiology, as well as gene repertoire of seed plants. However, shifts to a heterotrophic lifestyle have independently evolved twelve times in more than four thousand parasitic plants. Among these parasites, otherwise rare features have evolved repetitively at both the molecular and phenotypical levels, including reduced vegetative body, carrion mimicking, and abundant alien genetic materials. Here, I propose an integrated conceptual model to describe the general evolutionary trajectory of parasitic plants and provide a mechanistic explanation for their convergent evolution. This model connects our empirical understanding of the plants’ regulatory network with classic theories in molecular and population genetics. It emphasizes the cascading effects driven by the loss of photosynthesis as one major force shaping the genomic landscape of parasitic plants. In this paper, I review recent studies in the anatomy, physiology, and genetics of parasitic plants to support the photosynthesis-centered hypothesis of their convergent evolution. Focusing on non-photosynthetic holoparasites, I elucidate how they inevitably reach an evolutionary terminal status and highlight the utility of an explicitly described, falsifiable model for future studies in parasitic plants.

Biogeografía y evaluaciones de conservación de las especies de Lamourouxia (Orobanchaceae)

“…Considering the evidence obtained with this study and the comprehensive evaluation of the endemism of vascular plants in the SMS, it is suggested to include most threatened Lamourouxia species distributed in Mexico in the conservation law NOM-059- SEMARNAT-2010(SEMARNAT, 2010, and increase the protection in the eastern portion of this province relevant to the flora of Mexico. This kind of studies evaluating endemism and conservation status can be replicated particularly with holoparasitic genera, which have a high extinction rate because of the specificity of their host (Cai, 2023;Schneider and Moore, 2017), being threatened by multiple biotic, abiotic and anthropogenic pressures.…”

“…They represent about 1% of flowering plant diversity with ca. 4750 species (Heide-Jørgensen, 2013;Nickrent, 2020;Cai, 2023). Based on phylogenetic studies, it has been proposed that they evolved independently at least 12 times in equal number of orders and 27 families among angiosperms (Westwood et al, 2010;Nickrent, 2020;Krasylenko et al, 2021).…”

Plastid genome evolution in leafless members of the orchid subfamily Orchidoideae, with a focus onDegranvillea dermaptera

“…Leafless, heterotrophic plants provide opportunities to study the genomic consequences of extreme changes in nutritional mode, morphology, physiology, ecology, and evolutionary trajectories (e.g. Bidartondo, 2005;Westwood et al, 2010;Wickett et al, 2014;Těšitel, 2016;Twyford, 2018;Wicke and Naumann, 2018;Yuan et al, 2018;Cai, 2023;Sanchez-Puerta et al, 2023;Timilsena et al, 2023). Plastid genomes have been the focus of intense research over the past few decades, due to their high copy number per cell, relatively small sizes (kilobases for plastomes vs. megabases for nuclear genomes), role in photosynthetic function, and ease with which they can be sequenced via high-throughput technologies (Wicke et al, 2011;Jansen and Ruhlman, 2012;Ruhlman and Jansen, 2014;Twyford and Ness, 2017;Doyle, 2022).…”

Plastid genome evolution in leafless members of the orchid subfamily Orchidoideae, with a focus on Degranvillea dermaptera

“…Leafless heterotrophic plants provide opportunities to study the genomic consequences of extreme changes in nutritional mode, morphology, physiology, ecology, and evolutionary trajectories (e.g., Bidartondo, 2005;Westwood et al, 2010;Wickett et al, 2014;Těšitel, 2016;Twyford, 2018;Wicke and Naumann, 2018;Yuan et al, 2018;Cai, 2023;Sanchez-Puerta et al, 2023;Timilsena et al, 2023). Plastid genomes have been the focus of intense research over the past few decades, due to their high copy number per cell, relatively small sizes (kilobases for plastomes vs. megabases for nuclear genomes), role in photosynthetic function, and ease of sequencing via high-throughput technologies (e.g., Wicke et al, 2011;Jansen and Ruhlman, 2012;Ruhlman and Jansen, 2014;Twyford and Ness, 2017;Doyle, 2022).…”