Environmental variations drive polyploid evolution in neotropical Eugenia species (Myrtaceae)

Abstract

ABSTRACT. Polyploidy is one of the most important mechanisms of speciation and diversification in plant evolution. Polyploidy results in genetic variation among individuals of the same species and even between populations, and may be responsible for differences in environmental tolerance between populations of the same species. This study determined chromosome numbers of Eugenia L. (Myrtaceae, x = 11) for 26 populations of 14 species by conventional cytogenetic techniques. Nine species (13 populations) were diploid (2n = 2x = 22), but diploid and/or polyploid cytotypes were found in the other five species (13 populations), with 2n = 33, 2n = 44, and 2n = 55. Data on chromosome number/ploidy level for other Eugenia species/populations were collected from the literature and included in this cytogeographic analysis. For each collection point (32 species and 62 populations), environmental variables were recorded using georeferencing techniques through the DIVA-GIS v.7.5 program. Environmental variables such as temperature, altitude, rainfall, solar radiation, soil type, and vegetation were analyzed with the R program, using MannWhitney and chi-square tests, principal component analysis, and graphic analyses, such as scatterplots, boxplots, and barplot. Polyploid and diploid populations had different spatial distribution patterns and were found in areas subjected to different environmental conditions. Polyploid individuals were collected from locations with more adverse environmental conditions, usually at higher elevations than the diploid individuals. Polyploidy allows species to occur at locations with varying environmental conditions. As diploidy and polyploidy occur under different environmental conditions, species with cytotypes exhibit wide environmental tolerance.

When everything changes at once: finding a new normal after genome duplication

“…Some polyploids are found in drier, more ruderal or more extreme habitats than diploids (e.g. [138][139][140][141][142][143]). This may have important implications also in the context of climate change.…”

Cytogeography of the East Asian Tulips (Amana, Liliaceae)

“…This hypothesis has been supported by several investigations confirming that polyploidy has obvious advantages in adaptation and tolerance to environmental stress (McArthur and Sanderson 1999 [33]; Brochmann et al, 2004 [34]; Hijmans et al 2007 [35]). Areas with higher latitudes and altitudes are usually not good for the growth of plants due to the cold and dry climate, therefore, the percentage of polyploids generally increases when it goes from lower latitudes/altitudes to higher ones (Actinidia chinensis, Li et al, 2010 [36]; Claytonia perfoliata, Patrick, 2012 [37]; Eugenia, Silveira et al, 2016 [38]; Asparagus, Mousavizadeh et al, 2021 [39]; Peruzzi et al, 2012 [40]).…”

Phenotypic strategies for Jasione L. or the challenge that taxonomy face to recent floristic responses along western Eurasia

“…Nevertheless, further discussion should be involved in the migration responses for this genus. In fact, alterations in the structure and organization of vegetation should also be decisive for the capacity to accommodate germplasm (Silveira et al 2016). Under these critical environmental variations, new genetic combinations among different haplotypes, as well as introgressions and coalescence processes merged frequently (Schaal and Olsen 2000;Widmer and Lexer 2001;Prentice et al 2008;Heuertz et al 2010;Mattioni et al 2013;Feliner 2014;Jordan et al 2017).…”