Biology subjects

Ibiapino, A.

Publications and source records attributed to Ibiapino, A..

2 recordsLinked to original sources

bioRxiv2025

Cytogenetic Insights of C. argentinana Yunk. and C. parodiana Yunk., two species from section Subulatae (Cuscuta L. - Convolvulaceae)

The genus Cuscuta exhibits remarkable cytogenetic diversity, strongly influenced by heterochromatin dynamics. The genus is divided into four subgenera, the subgenus Grammica is almost exclusively found in the Americas, and South America is the first major diversification center. The section Subulatae consists of species primarily found in Argentina. To cytogenetically characterize the Cuscuta species of Subulatae and investigate the chromosomal evolution of the subgenus Grammica, CMA/DAPI banding, FISH with 5S and 35S rDNA, and flow cytometry were performed on C. argentinana and C. parodiana. Both species exhibited 2n = 30 with differences in chromosome size, heterochromatic banding patterns, and genome size. Cuscuta argentinana has smaller chromosomes and genome (1C = 1.49 Gbp) and a higher number of metacentric chromosomes and CMA/DAPI- bands, whereas C. parodiana (1C = 2.79 Gbp) exhibits heterochromatin accumulation and a higher number of submetacentric chromosomes and heterochromatin accumulation. While the number of 5S rDNA sites was the same (six sites), C. parodiana presented one more pair of 35S rDNA sites. The results suggest that genome variation in Cuscuta section Subulatae is associated with heterochromatin amplification. These findings contribute to understanding of Grammica diversification and the role of heterochomatin in the chromosomal evolution of the genus.

plant biology↗

bioRxiv2021

Karyotype asymmetry in Cuscuta L. subgenus Pachystigma reflects its repeat DNA composition

Cuscuta is a cytogenetically diverse genus, with karyotypes varying 18-fold in chromosome number and 89-fold in genome size. Each of its four subgenera also presents particular chromosomal features, such as bimodal karyotypes in Pachystigma. We used low coverage sequencing of the Cuscuta nitida genome (subgenus Pachystigma), as well as chromosome banding and molecular cytogenetics of three subgenus representatives, to understand the origin of bimodal karyotypes. All three species, C. nitida, C. africana (2n = 28) and C. angulata (2n = 30), showed heterochromatic bands mainly in the largest chromosome pairs. Eighteen satellite DNAs were identified in C. nitida genome, two showing similarity to mobile elements. The most abundant were present at the largest pairs, as well as the highly abundant ribosomal DNAs. The most abundant Ty1/Copia and Ty3/Gypsy elements were also highly enriched in the largest pairs, except for the Ty3/Gypsy CRM, which also labelled the pericentromeric regions of the smallest chromosomes. This accumulation of repetitive DNA in the larger pairs indicates that these sequences are largely responsible for the formation of bimodal karyotypes in the subgenus Pachystigma. The repetitive DNA fraction is directly linked to karyotype evolution in Cuscuta. HighlightsCuscuta subgenus Pachystigma contains species with strikingly bimodal karyotypes. The emergence of these karyotypes is linked to the enrichment of varied repetitive sequences in the largest chromosomal pairs.

plant biology↗