The landscape of karyotype diversity in Marantaceae

Abstract

Marantaceae is a pantropically distributed family, which includes species with ornamental and food potential. Chromosome number change and its outcomes, such as nuclear 2C value variation, provide valuable information for cytotaxonomy as well as about evolution and speciation of the different taxa. Here, we aimed to determine the 2n chromosome number of nine species and measure the nuclear 2C value of 23 species representing eight genera of Marantaceae. The chromosome number of six species and the 2C nuclear value of 18 species were reported for the first time. In addition, we performed the morphometric characterization and 5S rDNA mapping in Monotagma plurispicatum, which exhibited the lowest 2n chromosome number (2n = 12). The species exhibited notable chromosome number differences, 2n = 12, 24, 26, 36, 44, 46, 48 or 50 chromosomes. For each species, we found a stable somatic chromosome number. The mean 2C nuclear value also varied between the species from 2C = 0.63 pg (Ischnosiphon leucophaeus) to 13.49 pg (Saranthe eichleri), representing an intergeneric variation reaching 2,041%. M. plurispicatum chromosome number, karyogram and 5S rDNA mapping (chromosome 3) evidenced that its diploidy with complement set x = 6, with two metacentric (1 and 5), three submetacentric (3, 4 and 6), and one acrocentric (2) chromosome. Considering our findings and previously published data, we reinforce that polyploidy play an important role in the interspecific variation of chromosome number and/or nuclear genome size in Marantaceae, and that these genomic changes influence diversification and speciation in this family.