Format: ORAL

Sader MA1, Vaio M2, Urdampilleta JD1

1-Instituto Multidisciplinario de Biología Vegetal (IMBIV), Universidad de Córdoba-CONICET, Argentina 2- Laboratorio de Evolución y Domesticación de las Plantas, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Uruguay Corresponding author email: msader@imbiv.unc.edu.ar; jurdampilleta@imbiv.unc.edu.ar

The genus Solanum is quite diverse, containing a wide range of species including important crops like tomatoes, potatoes, and eggplants, as well as many wild species. The Cyphomandra clade is a group within the Solanum (Solanaceae), commonly known as the nightshade family. One of the most well-known members of this clade is S. betaceum (tree tomato or tamarillo). Members of the Cyphomandra are typically found in tropical and subtropical regions and their fruits are generally edible and used in culinary applications. Genome sizes (GS) within Solanum can vary significantly and Cyphomandra has giant genomes (Solanum GS mean=1.40pg, range 0.60-24.8pg, and Cyphomandra GS mean=10.71pg, range 6.80-24.80pg) compared to its cultivated relatives: Tomato (S. lycopersicum, 950Mb), Potato (S. tuberosum, 844 Mb) and Eggplant (S. melongena, 1,120 Mb). Giant genomes are characterized by often containing a high number of repetitive sequences and non-coding DNA. To understand and characterize the repetitive fraction, we sequenced DNA from four species (S. betaceum, S. glaucophyllum, S. confusum,S. stuckertii)using low coverage (0.1). We also estimated the genome size, performed a clustering analysis, and mapped the most abundant repeats using FISH. The estimated GS were 12.5pg, 17.3pg, 21.7pg and 23pg for S. glaucophyllum, S. stuckertii, S.confusum,and S. betaceum respectively. The repetitive fraction constitutes 54%, 53%, 63%, and 76% of the genome respectively, with the Ty3/gypsy-Tekay retrotransposon being the most abundant except in S. glaucophyllum (Ty3/gypsy-Ogre). Furthermore, we identified four distinct satellite DNA families in S. confusum, S. stuckertii and S. betaceum, with 0.45%, 1.93%, and 0.85% of repetitive fraction respectively, and 9 families in S. glaucophyllum (1.52%). We observed that in the species exists an accumulation of repetitive DNA sequences, especially retrotransposons, and different satellite families, confirming that these genomes are highly dynamic in their repetitive fraction.