Karyotype differentiation of locoto chile (Capsicum pubescens, Solanaceae) revealed by fluorescent banding and FISH mapping of satellite DNA

PALOMBO, N E; CARRIZO GARCÍA, C; SCHNEEWEISS, H; SCALDAFERRO, M

Catamarca

Congreso; XXXIX JORNADAS ARGENTINAS DE BOTÁNICA; 2023

Sociedad Argentina de Botánica

The hot chile Capsicum pubescens Ruiz & Pav. (2n = 2x = 24), commonly known as locoto or rocoto, is a regionally important food crop from the mid-highlands of South and Central America, with an increasing global demand. The studies about the genomic variation of locoto chile, including chromosomal differentiation, are still in their early stages. Fluorescent banding (CMA/DA/DAPI) and FISH mapping of two satellite DNA families (CapSat1 and CapSat4) were applied to assess karyotype variability in C. pubescens, using eight accessions from different lineages within the species. The cytogenetic markers employed were very useful for the identification of individual chromosome pairs and facilitated subsequent comparative analysis. The fluorescent banding unveiled previously unreported variability in heterochromatin content. The distribution pattern of CapSat1 and CapSat4 loci also showed variation among the sampled accessions, hybridizing on both heterochromatin and euchromatin regions. CapSat1 was more variable than CapSat4 regarding the number and position of FISH signals, with numerous heteromorphisms. Altogether, the results provide novel insights into the karyotype organization and differentiation in C. pubescens, however, the functional role of this variation is still uncertain. These findings establish a precedent for future cytogenetic and genomic investigations on locoto chile, enabling future breeding programs.