Diversity, phylogeny and evolution of the rapidly evolving genusPsidiumL. (Myrtaceae, Myrteae)

Abstract

Background and Aims Psidium is the 4th largest genus of Myrtaceae in the Neotropics. Psidium guajava is widely cultivated in the tropics for its edible fruit. It is commercially under threat due to the disease guava decline. P. cattleyanum is one of the 100 most invasive organisms in the world. Knowledge of the phylogenetic relationships within Psidium is poor. We aim to provide a review of the biology, morphology and ecology of Psidium, a phylogenetic tree, an infra-generic classification and a list of species. Methods Morphological and geographic data were obtained by studying Psidium in herbaria and in the field between 1988 and 2020. Forty-six herbaria were visited personally. A database of c. 6,000 specimens was constructed, and the literature was reviewed. Thirty species (c. 1/3 of the species in the genus) were sampled for molecular phylogenetic inference. Two chloroplast (psbA-trnH and ndhF) and two nuclear (ETS and ITS) regions were targeted. Phylogenetic trees were constructed using Maximum Likelihood (ML; RaxML) and Bayesian Inference (BI; MrBayes). Key Results Psidium is a monophyletic genus with four major clades recognized as sections. Section Psidium (ten species), to which P. guajava belongs, is sister to the rest of the genus; it is widespread across the Neotropics. Section Obversifolia (six species; restricted to the Brazilian Atlantic Forest), which includes P. cattleyanum, is sister to the innermost clade composed of sister sections Apertiflora (31 species; widespread but most diverse in the Brazilian Atlantic Forest) + Mitranthes (26 species; widespread in dry forests and probably diverse in the Caribbean). Characters associated to diversification within Psidium are discussed. Conclusions Research on prefoliation, colleters, leaf anatomy, leaf physiology, staminal development, placentation, and germination associated to the anatomy of the opercular plug is desirable. Studies are biased towards sections Psidium and Obversifolia, with other sections poorly known.

Genomic and epigenomic variation in Psidium species and their outcome under the yield and composition of essential oils

“…V Cat (1) 5.68 -VI Cat (2) , Gau (1) 7.09 6.83 -7.40 CG% I G ui (1) 34.33 -II Hib (2) , Gui (2) 35.29 35.07 -35.37 III Cat (1) , Gua (2) , Gua (1) , Hib (2) , Gui (1) , Psi (1) 36.15 35.90 -36.37…”

“…IV Cat (3) , Cat (1) , Gua (3) , Gua (7) , Gua (18) , Myr (1) , Mac (1) , Psi (2) 37.40 36.72 -38.17…”

“…V Cat (12) , Cat (1) , Gua (2) , Gua (8) , Gua (6) , Myr (4) , Myr (11) , Myr (1) , Gau (1) , Gau (1) , Fri (1) , Psi (1) 38.92 38.29 -39.62 VI Aci (2) , Cat (5) , Cat (2) , Gua (1) , Gua (3) , Myr (1) , Myr (7) , Gau (4) , Obl…”

“…The neotropical and monophyletic genus Psidium , family Myrtaceae, contains approximately 92 species 1 , hich are taxonomically classified in four sections: Psidium (10 species), Obversifolia (six species), Apertiflora (31 species) and Mitranthes (26 species) 2 . ~ 60 Psidium species occur in Brazil distributed in all biomes, in several phytogeographic domains, representing great diversification 3 .…”

“…Psidium guajava L. (guava tree, Psidium section) is the well-known species of the genus due to its relevance for fruit production 4 and medicinal value 5 , 6 . Other Psidium species, popularly called “araçás”, are potential genetic resources for breeding programs and medicinal purposes 7 , as well as they are relevant for taxonomic, ecological and evolutive studies in this genus 2 .…”