Lucas Costa, Natália Castro, Christopher E Buddenhagen, André Marques, Andrea Pedrosa-Harand, Gustavo Souza
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引用次数: 0
Abstract
Background and aims: Genomic changes triggered by polyploidy, chromosomal rearrangements, and/ or environmental stress are among factors that affect the activity of mobile elements, particularly Long Terminal Repeats Retrotransposons (LTR-RTs) and DNA transposons. Because these elements can proliferate and move throughout host genomes, altering the genetic, epigenetic and nucleotypic landscape, they have been recognized as a relevant evolutionary force. Beaksedges (Rhynchospora) stand out for their wide cosmopolitan distribution, high diversity (~400 spp.) and holocentric chromosomes related to high karyotypic diversity and a centromere-specific satDNA Tyba. This makes the genus an interesting model to investigate the interactions between repetitive elements, phylogenetic relationships, and ecological variables.
Methods: Here, we used comparative phylogenetic methods to investigate the forces driving the evolution of the entire set of mobile elements (mobilome) in the holocentric genus Rhynchospora. We statistically tested the impact of phylogenetic relationships, abundance of holocentromeric satDNA Tyba, diversity of repeatome composition, ecological variables, and chromosome number in mobile element diversification.
Key results: Tyba abundance was found to be inversely correlated with LTR-RT content. Decrease of LTR abundance and diversity was also related to increase in chromosome number (likely due to fission events), and colonization of dry environments in the northern hemisphere. In contrast, we found constant LTR insertions throughout time in species with lower chromosome numbers in rainier environments in South America. A multivariate model showed that different traits drive LTR abundance, especially repeat diversity and Tyba abundance. Other mobile elements, such as non-LTR RTs and DNA transposons had insufficient abundance to be included in our models.
Conclusions: Our findings suggest that LTR evolution is strongly impacted by the holocentric characteristics of Rhynchospora chromosomes, correlating with species diversification and biome shifts, and supporting a holokinetic drive model of evolution and a competitive scenario with Tyba. Altogether, our results present evidence of multi-trait influence on LTR-RT dynamics and provide a broader understanding of TE evolution in a macroevolutionary context.
期刊介绍:
Annals of Botany is an international plant science journal publishing novel and rigorous research in all areas of plant science. It is published monthly in both electronic and printed forms with at least two extra issues each year that focus on a particular theme in plant biology. The Journal is managed by the Annals of Botany Company, a not-for-profit educational charity established to promote plant science worldwide.
The Journal publishes original research papers, invited and submitted review articles, ''Research in Context'' expanding on original work, ''Botanical Briefings'' as short overviews of important topics, and ''Viewpoints'' giving opinions. All papers in each issue are summarized briefly in Content Snapshots , there are topical news items in the Plant Cuttings section and Book Reviews . A rigorous review process ensures that readers are exposed to genuine and novel advances across a wide spectrum of botanical knowledge. All papers aim to advance knowledge and make a difference to our understanding of plant science.