Geographic distribution and climatic niche comparison between diploid and polyploid cytotypes of South American genus Lessingianthus H.Rob. (Vernonieae, Asteraceae)

ANGULO MARÍA BETIANA; FLORENTÍN JAVIER ELÍAS; VIA DO PICO GISELA M.

PERSPECTIVES IN PLANT ECOLOGY EVOLUTION AND SYSTEMATICS

ELSEVIER GMBH

Año: 2023

1433-8319

The distribution of ploidy levels and their ecological associations were studied usingthe genus Lessingianthus (Vernonieae, Asteraceae) as a model system. This genus isvery complex from a cytogenetic point of view, with high cytotype diversity at theinterspecific and intraspecific levels and with a continuous distribution throughoutSouth America. So far, no previous studies have summarized chromosome count datafor Lessingianthus or addressed the cytogeography of the genus. In this study, theploidy levels of Lessingianthus species were determined by chromosome countsduring mitosis and ecological niche modelling (ENM) was used to compare theenvironmental associations of the diploid and polyploid cytotypes. In total, 28chromosome counts and six ploidy levels (2x, 4x, 6x, 8x, 10x, and 11x) were recorded.Among these counts, the chromosome numbers for three hexaploids with 2n= 96 (L.parvifolius, L. vepretorum and L. “bolivianensis” sp. ined.) and one decaploid taxonwith 2n= 160 (L. roseus) were reported for the first time. In addition, a new cytotype forL. laniferus (2n= 6x= 96) was also reported. The cytogeographic analysis resulted indetecting two geographic zones with high diversity of cytotypes and species. TheENMs showed that the areas of climatic suitability of diploids and polyploids are similarin extent, as well as the climatic requirements, showing high values of niche overlapwithin the environmental space. Our findings suggested that polyploidization inLessingianthus has not caused expansion to novel environmental conditions andphylogenetic niche conservatism (PNC) may explain the lack of niche differentiationbetween diploids and polyploids.