Abstract
Genome size, the total amount of DNA content in the cell nucleus, varies greatly among flowering plants. One factor underlying this variation is the environment under which plants evolve. Given this premise, harsh environmental conditions in arid regions may profoundly influence genome evolution. However, the specific impact of aridification on genome size evolution, particularly for African lineages, remains largely unexplored. Here, we investigate linkages between genome size evolution and ecological adaptation using the genus Cyphostemma in the grape family (Vitaceae) as a model. Cyphostemma species exhibit genome size expansion and remarkable morphological traits in arid environments, including succulent stems or leaves and loss of tendrils. Our biogeographic reconstruction, based on substantial taxon sampling (112 of 200 species), reveals that Cyphostemma originated in continental Africa during the late Eocene to Oligocene and has undergone rapid radiation since the middle Miocene, coinciding with intensified aridification and geological activity in eastern Africa. Incorporating extensive data on traits, habitats, genome size, and chromosome numbers, we show that Cyphostemma species with the largest genomes are succulent polyploids restricted to nutrient-rich limestone outcrops. Broad-scale analyses across eudicots further confirm that larger genomes are significantly associated with both succulence and arid habitats. Our findings reveal a strong association between genome size expansion, polyploidy, and adaptive traits, indicating that genome size is a hitherto neglected trait associated with the radiation of succulent plants during the African aridification in the Cenozoic.
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Claims 6
Claim · model-written summary
Cyphostemma shows genome expansion and succulent morphology in arid environments.
- Taxon
- Cyphostemma
Cyphostemmae0 - Outcome
- genome size expansione0
- Setting
- arid environmentse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cyphostemma species exhibit genome size expansion and remarkable morphological traits in arid environments, including succulent stems or leaves and loss of tendrils.”
Claim · model-written summary
Cyphostemma originated in continental Africa during the late Eocene to Oligocene.
- Taxon
- CyphostemmaCyphostemmae0
- Outcome
- originatede0
- Qualifier
- late Eocene to Oligocenee0
- Setting
- continental Africae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cyphostemma originated in continental Africa during the late Eocene to Oligocene”
Claim · model-written summary
Cyphostemma rapidly radiated since the middle Miocene alongside eastern African aridification and geological activity.
Not reportedTaxonDirection
Verbatim
e0“has undergone rapid radiation since the middle Miocene, coinciding with intensified aridification and geological activity in eastern Africa”
Claim · model-written summary
The largest Cyphostemma genomes occur in succulent polyploids on nutrient-rich limestone outcrops.
- Taxon
- CyphostemmaCyphostemmae0
- Material
- succulent polyploidse0
- Outcome
- largest genomese0
- Direction
- largeste0
- Setting
- nutrient-rich limestone outcropse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cyphostemma species with the largest genomes are succulent polyploids restricted to nutrient-rich limestone outcrops”
Claim · model-written summary
Across eudicots, larger genomes are significantly associated with succulence.
- Taxon
- eudicotseudicotyledonse0
- Organ / stage
- succulencee0
- Outcome
- larger genomese0
- Direction
- largere0
Verbatim
e0“Broad-scale analyses across eudicots further confirm that larger genomes are significantly associated with both succulence and arid habitats”
Claim · model-written summary
Across eudicots, larger genomes are significantly associated with arid habitats.
- Taxon
- eudicotseudicotyledonse0
- Outcome
- larger genomese0
- Direction
- largere0
- Setting
- arid habitatse0
Verbatim
e0“Broad-scale analyses across eudicots further confirm that larger genomes are significantly associated with both succulence and arid habitats”