Evolutionary and Biogeographic Insights on the Macaronesian Beta-Patellifolia Species (Amaranthaceae) from a Time-Scaled Molecular Phylogeny

Abstract

The Western Mediterranean Region and Macaronesian Islands are one of the top biodiversity hotspots of Europe, containing a significant native genetic diversity of global value among the Crop Wild Relatives (CWR). Sugar beet is the primary crop of the genus Beta (subfamily Betoideae, Amaranthaceae) and despite the great economic importance of this genus, and of the close relative Patellifolia species, a reconstruction of their evolutionary history is still lacking. We analyzed nrDNA (ITS) and cpDNA gene (matK, trnH-psbA, trnL intron, rbcL) sequences to: (i) investigate the phylogenetic relationships within the Betoideae subfamily, and (ii) elucidate the historical biogeography of wild beet species in the Western Mediterranean Region, including the Macaronesian Islands. The results support the Betoideae as a monophyletic group (excluding the Acroglochin genus) and provide a detailed inference of relationships within this subfamily, revealing: (i) a deep genetic differentiation between Beta and Patellifolia species, which may have occurred in Late Oligocene; and (ii) the occurrence of a West-East genetic divergence within Beta, indicating that the Mediterranean species probably differentiated by the end of the Miocene. This was interpreted as a signature of species radiation induced by dramatic habitat changes during the Messinian Salinity Crisis (MSC, 5.96–5.33 Mya). Moreover, colonization events during the Pleistocene also played a role in shaping the current diversity patterns among and within the Macaronesian Islands. The origin and number of these events could not be revealed due to insufficient phylogenetic resolution, suggesting that the diversification was quite recent in these archipelagos, and unravelling potential complex biogeographic patterns with hybridization and gene flow playing an important role. Finally, three evolutionary lineages were identified corresponding to major gene pools of sugar beet wild relatives, which provide useful information for establishing in situ and ex situ conservation priorities in the hotspot area of the Macaronesian Islands.

Phylogenetic relationships and phylogeography of relevant lineages within the complex Campanulaceae family in Macaronesia

“…Payseur & Rieseberg, ) and within the Campanulaceae family is a likely cause of the discrepancy between the nuclear and chloroplast trees (Wendling et al, ). The significant quantity of loops that can be found in the NeighborNet network in this study, further leads to the hypothesis of early hybridization between different species along the evolutionary story of Campanulaceae, and a similar case of was reported by Romeiras, Vieira, et al () for the Macaronesian Beta ssp . (Amarathaceae family).…”

“…The estimation of divergence times in this study provides information about the diversification of relevant lineages of Campanulaceae species in Macaronesia, such as Azorina , Musschia , C. jacobaea , C. bravensis , and W. lobelioides subsp. lobelioides , revealing that diversification was quite recent, during the late Pliocene and Pleistocene: a recurrent pattern reported for this biogeographic region (e.g., Bateman, Rudall, & Moura, ; Romeiras, Vieira, et al., ; Romeiras et al., ).…”

Laboratory evidence for the hematopoietic potential of Beta vulgaris leaf and stalk extract in a phenylhydrazine model of anemia

“…It is distributed worldwide including subtropical and tropical countries in Africa and in Asia (7). The leaf, leaf stalks, and roots of beet plants are edible and may grow to 0.5–0.75 meters.…”

Genetic diversity of Patellifolia patellaris from the Iberian Peninsula, a crop wild relative of cultivated beets

“…Microsatellite markers are suited to calculate genetic distances among occurrences and to quantify genetic differentiation within this collection. Nuclear ribosomal DNA (nrDNA), internal transcribed spacer sequences (ITS) and/or chloroplast DNA markers are tools widely used to analyse and establish phylogenetic relationships between species (Romeiras et al 2016) and between occurrences of the same species as well (Villain 2007). The latter two marker classes may help to explain why the geographic distribution pattern of occurrences does not fully agree with the observed genetic patterns.…”

“…The existence of differences in nrDNA or cpDNA marker diversity in neighbouring occurrences would support this assumption. Romeiras et al (2016) observed polymorphisms in nrDNA (ITS) and cpDNA gene (matK, trnH-psbA, trnL intron, rbcL) sequences of P. patellaris that are available for such kind of phylogeographic investigations. Until such work has been implemented, further priority setting for in situ conservation actions would be premature.…”