<p><strong>Phylogenetic relationships of <em>Echeveria </em>(Crassulaceae) and related genera from Mexico, based on three DNA barcoding loci</strong></p>

Abstract

Mexico is considered as diversification and endemism center of the genus Echeveria. Previous tree inference studies have shown the genus to be non-monophyletic in relation to other genera, but sampling for Echeveria has been poor, and has not allowed to understand the relationships within the genus. In this work, Bayesian and maximum likelihood phylogenetic analysis were performed, using a combined standard DNA barcoding loci matrix (rbcL, matK and ITS2) and GenBank ITS2 accessions for Graptopetalum, some Sedum and few Echeveria taxa. The selection of taxa encompasses all current infrageneric categories of the genus Echeveria, as well as species from genera previously associated with it. The inferred consensus trees suggested that Echeveria is paraphyletic. Instead, four main clades were retrieved within the “Echeveria group”: Clade I includes exclusively Pachyphytum species. Clade II is formed by the majority of series Urbiniae; Clade III encompasses series Chloranthae, Ciliatae, Echeveria, Mucronatae, Nudae, Racemosae, Thyrsiflorae, Pachyphytum cuicatecananum and Thompsonella; Clade IV contains series Angulatae, Gibbiflorae, Occidentales, Pruinosae, Secundae, some Urbiniae species, Valvatae. genera Cremnophila, Graptopetalum and Reidmorania. Pachyphytum and Thompsonella were retrieved as monophyletic groups, but the first outside Echeveria while the latter inside. Results of our study suggest that Echeveria and the Echeveria Group require a redefinition.

The Conservation of Chloroplast Genome Structure and Improved Resolution of Infrafamilial Relationships of Crassulaceae

“…The subfamily Kalanchoideae include approximately 240 species in four genera ( Smith et al, 2019 ), i.e., Adromischus Lem., Cotyledon L., Kalanchoe , and Tylecodon Toelken, and the inter- and intrageneric relationships have been exclusively assessed in a few separate studies ( Gehrig et al, 2001 ; Mort et al, 2005 ; Nowell, 2008 ). The largest and most complex subfamily Sempervivoideae contain 28 genera and over 1,000 species ( Thiede and Eggli, 2007 ), and the inter- and intrageneric relationships have been investigated by a considerable number of studies (e.g., Mes et al, 1997 ; Jorgensen and Frydenberg, 1999 ; Mort et al, 2002 ; Acevedo-Rosas et al, 2004 ; Fairfield et al, 2004 ; Mayuzumi and Ohba, 2004 ; Gontcharova et al, 2006 ; Carrillo-Reyes et al, 2008 , 2009 ; Yost et al, 2013 ; Zhang et al, 2014 ; Klein and Kadereit, 2015 ; Nikulin et al, 2016 ; Vázquez-Cotero et al, 2017 ; de la Cruz-López et al, 2019 ). These phylogenetic studies have led to the recognition of five tribes within Sempervivoideae by Thiede and Eggli (2007) , i.e., Aeonieae ( Aeonium Webb and Berth., Aichryson Webb and Berth., and Monanthes Haw.…”

Chromosome Number, Ploidy Level, and Nuclear DNA Content in 23 Species of Echeveria (Crassulaceae)

“…The increase in the chromosome number has an advantage in colonizing new environments, as the distribution of this series confirms in Mexico, where it could be hypothesized that the diploidization process was the main mechanism of series diversification. It is relevant to mention that data on the chromosome number and DNA content can help in the phylogenetic resolution of this genus, because even though important molecular studies in the Gibbiflorae series show a monophyletic origin, there are still some phylogenetic relationships that need to be resolved [ 73 ].…”

Echeveria andreae (Crassulaceae), una nueva especie de los bosques templados de las montañas de la Mixteca Alta, Oaxaca, México

“…Un análisis filogenético previo en donde se incluyen la mayoría de las especies de Echeveria de México, indica que la serie Racemosae no es monofilética (de la Cruz-López et al, 2019). Al interior de la ser.…”

“…Su distribución geográfica abarca desde el sur de los Estados Unidos (Texas) hasta Argentina en Sudamérica, excluyendo las Antillas (Pino et al, 2019;Reyes-Santiago et al, 2011;Vázquez-Cotero et al, 2017;Walther, 1972). Las especies de Echeveria se agrupan en 17 series (Walther, 1972), algunas de las cuales han sido recobradas como parafiléticas en análisis filogenéticos recientes, incluyendo a la serie Racemosae (de la Cruz-López et al, 2019). Las especies de Echeveria habitan preferentemente en los afloramientos rocosos o en los enclaves xerofíticos en bosques templados, matorrales xerófilos, bosques tropicales caducifolios, o como epífitas en selvas medianas perennifolias y bosques mesófilos de montaña, en altitudes que van desde los 100 hasta los 4,100 m snm (Reyes-Santiago et al, 2011).…”