Lineage-specific evolution of mangrove plastid genomes

Area of Science:

• Plant Biology
• Evolutionary Genetics
• Genomics

Background:

• Mangroves, coastal plants from terrestrial ancestors, offer unique insights into evolutionary convergence and lineage-specific traits.
• Understanding mangrove genetic makeup is crucial for studying their adaptation to diverse environments.

Purpose of the Study:

• To compare chloroplast genomes across 21 mangrove species representing major phylogenetic clades.
• To investigate gene order, content, genome size, repeat content, sequence diversity, and selection pressures within mangrove chloroplast genomes.

Main Methods:

• Comparative analysis of 21 mangrove species' complete chloroplast genomes.
• Examination of gene order, content, genome size, and repeat regions.
• Sequence diversity analysis focusing on IR and SC regions.
• Positive selection analysis on specific ribosomal protein genes.

Main Results:

• Chloroplast gene order, content, and genome size are largely conserved among mangroves.
• Specific gene losses (psaZ) and inversions (rpl23) were observed in certain species.
• Repeat content varied by species but was conserved within orders; IR regions were highly conserved except in ferns.
• Positive selection was detected on the rps7 gene in a specific clade (fabids), but not in other lineages.

Conclusions:

• Convergent evolutionary dynamics do not leave a significant signal on the mangrove plastid genome.
• The study provides a valuable resource of complete chloroplast genomes for future mangrove research.
• Plastid genome conservation highlights unique evolutionary pathways in mangroves.