Correlations among chromosome numbers, nuclear dna contents, and climatic variables of South American Cactaceae in a phylogenetic context

LAS PEÑAS M. L.; BAUK K.; ROSSI N.; BERNARDELLO G.

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2024 vol. 141 p. 87 - 101

0024-4066

Cactaceae are American members of arid and semi-arid regions, and also present in tropical forests and temperate climates. The taxonomy is complex due to large morphological variability, and polyploidy is a significant mechanism in cactus. This is a significant mechanism in cactus speciation, associated with geographical and environmental range expansions. In South America, Cactaceae have a wide distribution range, being an informative model to examine the correlation between ploidy levels and genome sizes with geographic and bioclimatic variables. We tested whether ploidy levels and DNA contents are related to altitude and the 19 WorldClim variables and we mapped chromosome numbers and DNA amounts on a molecular phylogeny to interpret their evolution. Pearson correlation tests between the response variables and each climatic variable and performed a multivariate analysis to analyze the variation pattern among variables and chromosome numbers. Our data suggests that polyploidy had independent origins within each subfamily. Chromosome numbers are related to variables associated with temperature, whereas DNA contents mostly are related to precipitation. A negative correlation between the Cx-values and the increase in the ploidy level was observed. Based on the results, the small genome can be considered ecologically important as an adaptation to higher temperatures and droughts.