Format: ORAL

Nomar Espinosa Waminal, Frank R. Blattner, and Drte Harpke

Leibniz Insitute of Plant Genetics and Crop Plant Research

Spring crocuses, which comprise ten diploid and two polyploid species, as well as a polyploid complex, show diverse chromosome numbers (2n = 2x = 8, 10, 12, 14, 16, 28; 2n = 4x = 16, 18, 20, 22). Phylogenomic data revealed a high rate of dysploid karyotype changes among the diploid taxa, reducing the chromosome number from 2n = 28 to 2n = 8 while increasing genome size within a few million years. To infer the role of repeat expansion and chromosomal rearrangements in descending dysploidy, we characterized the types and abundances of repetitive genomic elements from each taxon and performed a comparative karyotype analysis in a phylogenomic context. FISH analysis of six repeat families and chromosome painting suggest a concerted action of descending dysploidy and a burst of repetitive DNA elements as drivers to the reduction of chromosome number while increasing genome size in more recently evolved taxa. This work provides insights into dysploidy in ser. Verni and an opportunity to develop approaches to study other dysploid-rich clades in plants.