AUTHOR=Granados-Aguilar Xochitl , Granados Mendoza Carolina , Cervantes Cristian Rafael , Montes José Rubén , Arias Salvador 

TITLE=Unraveling Reticulate Evolution in Opuntia (Cactaceae) From Southern Mexico

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.606809

DOI=10.3389/fpls.2020.606809

ISSN=1664-462X

ABSTRACT=<p>The process of hybridization occurs in approximately 40% of vascular plants, and this exchange of genetic material between non-conspecific individuals occurs unequally among plant lineages, being more frequent in certain groups such as <italic>Opuntia</italic> (Cactaceae). This genus is known for multiple taxonomic controversies due to widespread polyploidy and probable hybrid origin of several of its species. Southern Mexico species of this genus have been poorly studied despite their great diversity in regions such as the Tehuacán-Cuicatlán Valley which contains around 12% of recognized Mexico’s native <italic>Opuntia</italic> species. In this work, we focus on testing the hybrid status of two putative hybrids from this region, <italic>Opuntia tehuacana</italic> and <italic>Opuntia pilifera</italic>, and estimate if hybridization occurs among sampled southern opuntias using two newly identified nuclear intron markers to construct phylogenetic networks with HyDe and Dsuite and perform invariant analysis under the coalescent model with HyDe and Dsuite. For the test of hybrid origin in <italic>O. tehuacana</italic>, our results could not recover hybridization as proposed in the literature, but we found introgression into <italic>O. tehuacana</italic> individuals involving <italic>O. decumbens</italic> and <italic>O. huajuapensis</italic>. Regarding <italic>O. pilifera</italic>, we identified <italic>O. decumbens</italic> as probable parental species, supported by our analysis, which sustains the previous hybridization hypothesis between <italic>Nopalea</italic> and <italic>Basilares</italic> clades. Finally, we suggest new hybridization and introgression cases among southern Mexican species involving <italic>O. tehuantepecana</italic> and <italic>O. depressa</italic> as parental species of <italic>O. velutina</italic> and <italic>O. decumbens</italic>.</p>