Evidence linking life‐form to a major shift in diversification rate inCrassula

Abstract

Premise: Plants have evolved different ecological strategies in response to environmental challenges, and a higher lability of such strategies is more common in plant groups that adapt to various niches. Crassula (Crassulaceae), occurring in varied mesic to xeric habitats, exhibits a remarkable diversity of life-forms. However, whether any particular life-form trait has shaped species diversification in Crassula has remained unexplored. This study aims to investigate diversification patterns within Crassula and identify potential links to its life-form evolution. Methods: A phylogenetic tree of 140 Crassula taxa was reconstructed using plastid and nuclear loci and dated based on the nuclear DNA information only. We reconstructed ancestral life-form characters to estimate the evolutionary trends of ecophysiological change, and subsequently estimated net diversification rates. Multiple diversification models were applied to examine the association between certain life-forms and net diversification rates. Results: Our findings confirm a radiation within Crassula in the last 10 million years. A configuration of net diversification rate shifts was detected, which coincides with the emergence of a speciose lineage during the late Miocene. The results of ancestral state reconstruction demonstrate a high lability of life-forms in Crassula, and the traitdependent diversification analyses revealed that the increased diversification is strongly associated with a compact growth form. Conclusions: Transitions between life-forms in Crassula seem to have driven adaptation and shaped diversification of this genus across various habitats. The diversification patterns we inferred are similar to those observed in other major succulent lineages, with the most-speciose clades originating in the late Miocene.

Ten Plastomes of Crassula (Crassulaceae) and Phylogenetic Implications

“…[ 7 , 11 , 12 ]. The monophyly of the subgenus Crassula was well supported in two recent molecular phylogenetic studies [ 9 , 10 ]. Nevertheless, the monophyly of subgenus Disporocarpa is still controversial [ 9 , 10 ].…”

“…The monophyly of the subgenus Crassula was well supported in two recent molecular phylogenetic studies [ 9 , 10 ]. Nevertheless, the monophyly of subgenus Disporocarpa is still controversial [ 9 , 10 ]. Thus, more evidence and further investigations are required to clarify the phylogenetic relationships of Crassula .…”

“…These subfamilies can be further subdivided into seven major clades: Crassula (Crassuloideae), Kalanchoe (Kalanchoideae), and the other five clades (Sempervivum, Leucosedum, Aeonium, Acre, and Telephium), which form the largest subfamily Sempervivoideae [ 3 , 4 , 5 , 6 , 8 ]. The genus Crassula , with about 200 accepted species, is the only unique genus in the clade Crassula, the second-largest genus of Crassulaceae, and significantly contributes to the diversity of Crassulaceae [ 3 , 9 , 10 ]. Previous taxonomic revision of Crassula recognized two subgenera: Crassula L. and Disporocarpa Fischer & C.A.…”

From southern Africa and beyond: historical biogeography of a monocotyledonous bulbous geophyte

“…During the Middle Miocene, the vegetation of South Africa was likely tropical, which gave way to more xerophytic shrubland by Late Miocene due to a global cooling climate (Pound et al, 2012). This time period is associated with diversification in the Crassulaceae (Lu et al, 2022) and also the expansion of C4 grasslands/savannas at a global scale (Bobe, 2006; Senut et al, 2009). Current biogeographical patterns of Aloe suggest dispersal from southern Africa to East Africa as seasonality and aridification increased across the continent within the past ∼16 my (Grace et al, 2015).…”

Bioefficacy of hydroxytyrosol-rich food supplements on preventing lipid peroxidation in healthy men

“…During the Middle Miocene, the vegetation of South Africa was likely tropical, which gave way to more xerophytic shrubland by Late Miocene due to a global cooling climate (Pound et al, 2012). This time period is associated with diversification in the Crassulaceae (Lu et al, 2022) and also the expansion of C4 grasslands/savannas at a global scale (Bobe, 2006;Senut et al, 2009). Current biogeographical patterns of Aloe suggest dispersal from southern Africa to East Africa as seasonality and aridification increased across the continent within the past ~16 my (Grace et al, 2015).…”