First genomic insights into the Mandevilla genus

Area of Science:

• Plant genomics
• Ornamental horticulture
• Apocynaceae family evolution

Background:

• Mandevilla is a commercially important ornamental genus with limited genetic and taxonomic understanding.
• Existing knowledge gaps hinder effective breeding and conservation efforts for Mandevilla species.

Purpose of the Study:

• To improve the genetic knowledge of the Mandevilla genus.
• To resolve taxonomic uncertainties and understand the evolutionary relationships among 55 Mandevilla accessions.
• To develop genomic resources for future research and breeding.

Main Methods:

• Genome size determination via flow cytometry.
• Plastid (cpDNA) and nuclear (nuDNA) genome sequencing and assembly.
• DNA superbarcoding for phylogenetic analysis.
• Bioinformatic annotation for protein prediction.
• Development and validation of simple sequence repeat (SSR) markers.
• Integration with ITS1 haplotyping and cpDNA barcoding.

Main Results:

• Triploid genome size of Mandevilla determined (1,512.64 Mb).
• Assembly of plastidial genome (cpDNA) and draft nuclear genome (nuDNA).
• cpDNA effective for Apocynaceae phylogenesis; nuDNA assembly yielded 37,811 predicted amino acid sequences, including 10,562 full-length proteins.
• Identified nine proteins involved in monoterpene indole alkaloid (MIA) biosynthesis.
• Developed 23 highly informative SSR markers (PIC = 0.62).
• Phylogenetic analyses indicated complex relationships, suggesting most accessions are interspecific hybrids, likely with Mandevilla sanderi as the maternal parent.

Conclusions:

• The study provides a significant advancement in understanding Mandevilla genetics and taxonomy.
• Developed genomic resources, including SSR markers, will facilitate future research and breeding programs.
• The findings suggest widespread hybridization within the genus, complicating species identification and necessitating further investigation.