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Plastome Evolution in the Sole Hemiparasitic Genus Laurel Dodder (Cassytha) and Insights into the Plastid Phylogenomics of Lauraceae
- Source :
- Genome Biology and Evolution
- Publication Year :
- 2017
- Publisher :
- Oxford University Press (OUP), 2017.
-
Abstract
- To date, little is known about the evolution of plastid genomes (plastomes) in Lauraceae. As one of the top five largest families in tropical forests, the Lauraceae contain many species that are important ecologically and economically. Lauraceous species also provide wonderful materials to study the evolutionary trajectory in response to parasitism because they contain both nonparasitic and parasitic species. This study compared the plastomes of nine Lauraceous species, including the sole hemiparasitic and herbaceous genus Cassytha (laurel dodder; here represented by Cassytha filiformis). We found differential contractions of the canonical inverted repeat (IR), resulting in two IR types present in Lauraceae. These two IR types reinforce Cryptocaryeae and Neocinnamomum—Perseeae–Laureae as two separate clades. Our data reveal several traits unique to Cas. filiformis, including loss of IRs, loss or pseudogenization of 11 ndh and rpl23 genes, richness of repeats, and accelerated rates of nucleotide substitutions in protein-coding genes. Although Cas. filiformis is low in chlorophyll content, our analysis based on dN/dS ratios suggests that both its plastid house-keeping and photosynthetic genes are under strong selective constraints. Hence, we propose that short generation time and herbaceous lifestyle rather than reduced photosynthetic ability drive the accelerated rates of nucleotide substitutions in Cas. filiformis.
- Subjects :
- 0301 basic medicine
Cassytha
Genome, Plastid
Evolution, Molecular
Lauraceae
03 medical and health sciences
Phylogenetics
Phylogenomics
Cassytha filiformis
Botany
plastid genome
Genetics
Plastid
Phylogeny
Ecology, Evolution, Behavior and Systematics
Plant Proteins
Gene Rearrangement
genome rearrangement
biology
Inverted Repeat Sequences
Gene rearrangement
biology.organism_classification
substitution rate
laurel
030104 developmental biology
Chloroplast DNA
hemiparasitic plant
Pseudogenes
Research Article
Subjects
Details
- ISSN :
- 17596653
- Volume :
- 9
- Database :
- OpenAIRE
- Journal :
- Genome Biology and Evolution
- Accession number :
- edsair.doi.dedup.....81b53cf8209c14e2cb58a432376d5880