THE REPETITIVE COMPOSITION OF PASSIFLORA GENOMES

SADER, M. A.; COSTA, Z. P.; CARNEIRO VIEIRA M. L.; CAUZ-SANTOS L. A.

Natal

Congreso; 67º Congresso Brasileiro de Genética - 2022; 2022

Sociedad Brasilera de Genética

Passionfruit species (Passiflora, Passifloraceae) are much appreciated for their exotic flowers and edible fruits. Passiflora is the richest genus (520 spp) and is subdivided into 4 subgenera (Passiflora, Decaloba, Deidamioides and Astrophea). Species are very diverse in morphological aspects, and also have a substantial variation in chromosome size andnumber. Regarding genome size, there is a 10-fold variation, which is not attributed to polyploidy. Variation in genomesize and chromosome number is common in plants, but its role in species evolution is continuously under investigation.Repetitive sequences are ubiquitous and important drivers of the structure and evolution of plant genomes, having greatinfluence in size variation and large-scale genome organization. Hence, an in-silico approach was taken to study the organization and diversification of the repetitive elements in 19 species of the Passiflora genus, including representativesof the four subgenera, expressing its known range in genome size variation. For this, low-coverage Illumina sequenceswere analyzed in the RepeatExplorer tool. In short, it performs graph-based clustering to identify repetitive elementsand uses a number of additional programs to annotate and quantify them. Results show the repetitive portion of all thespecies? genomes. The repetitive portion ranged from 22.2, in P. organensis (Decaloba) to 81.7% in P. alata (Passiflora). In general, species of the subgenus Decaloba presented the smallest portions of repetitive elements and species ofthe subgenus Passiflora the highest ones. Retrotransposons of the LTR order were the most frequent. Overall, the Gypsysuperfamily was more frequent than the Copia superfamily. Interestingly, elements classified as LINEs were recognizedonly in Decaloba. Satellite DNA clusters were identified in the Passiflora subgenus, and in greater proportions in Decaloba. Considering all species, the Tekay lineage is the most frequent, followed by Angela and Athila. Angela was notfound in Decaloba. The comparative analysis considering all species suggests that they are very diverse, with just a fewclusters shared between them. In general, the most shared clusters within each subgenus belong to the most frequentlineage found in that subgenus. Tekay and Angela seem to have influenced the increase in the genome sizes, since theypredominant in species with larger genomes. The Decaloba species seem to have developed mechanisms to silence oreliminate some elements, specifically Angela, remaining with smaller genomes. In this study all types of repeat classeswere studied in representatives of the four Passiflora subgenera, providing a valuable resource for comparative genomicanalysis and support for Passiflora genome evolution investigation