Recent deep-level phylogenies of the basal papilionoid legumes (Leguminosae, Papilionoideae) have resolved many clades, yet left the phylogenetic placement of several genera unassessed. The phylogenetically enigmatic Amazonian monospecific genus Petaladenium had been believed to be close to the genera of the Genistoid Ormosieae clade. In this paper we provide the first DNA phylogenetic study of Petaladenium and show it is not part of the large Genistoid clade, but is a new branch of the Amburaneae clade, one of the first-diverging lineages of the Papilionoideae phylogeny. This result is supported by the chemical observation that the quinolizidine alkaloids, a chemical synapomorphy of the Genistoids, are absent in Petaladenium. Parsimony and Bayesian phylogenetic analysis of nuclear ITS/5.8S and plastid matK and trnL intron agree with a new interpretation of morphology that Petaladenium is sister to Dussia, a genus comprising ∼18 species of trees largely confined to rainforests in Central America and northern South America. Petaladenium, Dussia, and Myrospermum have papilionate flowers in a clade otherwise with radial floral symmetry, loss of petals or incompletely differentiated petals. Our phylogenetic analyses also revealed well-supported resolution within the three main lineages of the ADA clade (Angylocalyceae, Dipterygeae, and Amburaneae). We also discuss further molecular phylogenetic evidence for the undersampled Amazonian genera Aldina and Monopteryx, and the tropical African Amphimas, Cordyla, Leucomphalos, and Mildbraediodendron.
Winged males of leaf-cutting ants are considered an ephemeral reproductive caste only produced before the mating flight season. Although much is known about the yeast diversity found in fungus gardens of attine ants, no study has focused on the yeasts associated with males of leaf-cutting ants. Here, we surveyed the yeasts on the integuments of males of Atta sexdens rubropilosa and assessed their potential role in the attine ant-microbe symbiosis. Using culture-dependent techniques, we found yeasts to be abundant on the integuments of males (54.5 %, n = 200 alates). A total of 242 yeast strains were obtained representing six orders, ten genera and 25 species. Strains of Aureobasidium, Cryptococcus, Hannaella and Rhodotorula were prevalent on the integuments and likely originated from the fungus garden of the parental nest or from the soil. The majority of strains (87.1 %) produced at least one of the evaluated enzymes: pectinase, polygalacturonase, cellulase, xylanase, ligninases and lipase. Aureobasidium pullulans accounted for the highest number of strains that produced all enzymes. In addition, yeasts showed the ability to assimilate the resulting oligosaccharides, supporting observations of other studies that yeasts may be involved in the plant biomass metabolism in the fungus gardens. Because winged males harbor several yeasts with putative functional roles, these fungi may take part and be beneficial in the microbial consortia of the new incipient nest.
a b s t r a c t Cellular and extracellular polysaccharides of the lichenized fungus Peltigera canina photobiont Nostoc muscorum (UTEX-2493) were evaluated. From EPS a linear (1 ? 4)-linked b-D-xylan was chemically characterized, and because of this and other findings involving lichenized fungi it could be proposed that this polymer may be typical of photobionts isolated from lichen thalli. From cellular biomass extracts a complex polysaccharide formed mainly of L-arabinose (2,3-O-Me 2 -, 24.8%) and D-xylose (2,3-O-Me 2 -, 10.6%) both units (1 ? 4)-linked was described. A smaller part of this structure has b-L-Arap and b-D-Xylp units branched at O-3 by a-D-Manp units, which in turn presents O-3 or O-2 single-unit substitution by a-D-Manp or a-L-Fucp as non-reducing ends. Arabinosyl residues were found to be in the b-L-arabinopyranosyl form, different from the most common form described in plant cell wall polysaccharides, a-L-arabinofuranosyl (Araf). Both polymers characterized in this work were not previously described when analyzing Nostoc sp. or cyanobacteria in general.
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