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A new study of the phylogeny of Cereus investigates generic monophyly and previous subgeneric classification. A coalescent approach was used to assess phylogenetic relationships among Cereus species based on nuclear orthologous genes captured by the Cactaceae591 probe set. The analysis included two unusual new taxa from eastern and northern Brazil to ascertain their position within the genus. Amongst the additional taxa, one was found to be early derived to the Atlantic Forest and coastal Cereus species and is described as C. ingens. Its imposing habit, considerably broader flower, yellow fruits and large seeds differentiate it from other Cereus species, and its inland agreste forest habitat in Minas Gerais and Bahia leads it to be categorized as Endangered, as little remains of this vegetation type. A second new species, C. gerardi, is described from the state of Tocantins (northern Brazil). Vegetatively this taxon is remarkable for resembling members of Pilosocereus, but has typical Cereus flowers, matching those of the type of the genus, C. hexagonus. The definition and relationships of the genus within the tribe Cereeae were made more evident, partly recovering three of the four pre‐existing subgenera. [ABSTRACT FROM AUTHOR]

Premise: Pilosocereus (Cactaceae) is an important dry forest element in all subregions and transitional zones of the neotropics, with the highest diversity in eastern Brazil. The genus is subdivided into informal taxonomic groups; however, most of these are not supported by recent molecular phylogenetic inferences. This lack of confidence is probably due to the use of an insufficient number of loci and the complexity of cactus diversification. Here, we explored the species relationships in Pilosocereus in more detail, integrating multilocus phylogenetic approaches with the assessment of the ancestral range and the effect of geography on diversification shifts. Methods: We used 28 nuclear, plastid, and mitochondrial loci from 54 plant samples of 31 Pilosocereus species for phylogenetic analyses. We used concatenated and coalescent phylogenetic trees and Bayesian models to estimate the most likely ancestral range and diversification shifts. Results: All Pilosocereus species were clustered in the same branch, except P. bohlei. The phylogenetic relationships were more associated with the geographic distribution than taxonomic affinities among taxa. The genus began diversifying during the Plio‐Pleistocene transition in the Caatinga domain and experienced an increased diversification rate during the Calabrian age. Conclusions: We recovered a well‐supported multispecies coalescent phylogeny. Our results refine the pattern of rapid diversification of Pilosocereus species across neotropical drylands during the Pleistocene and highlight the need for taxonomic rearrangements in the genus. We recovered a pulse of diversification during the Pleistocene that was likely driven by multiple dispersal and vicariance events within and among the Caatinga, Cerrado, and Atlantic Forest domains. [ABSTRACT FROM AUTHOR]

Cereus insularis (Cereeae, Cactaceae) is an insular endemic and dominant element of the vegetation of Fernando de Noronha Islands (FNI), a Neotropical archipelago 350 km from mainland Brazil. Here, we estimate the levels of genetic diversity for C. insularis and investigate its genetic relationship with the closely allied C. fernambucensis , which is widespread along the Brazilian coast. We genotyped and analysed 112 individuals for ten nuclear microsatellite markers to understand genetic connectivity between insular and mainland populations. The levels of genetic diversity for this species indicate an absence of genetic erosion. Furthermore, the expected heterozygosity in C. insularis is consistent with a long-term colonization process of FNI. We identify signatures of recent and bilateral gene flow among mainland and insular populations. We explain our results taking into consideration the biogeographic hypothesis to explain the peripatric origin of C. insularis. Overall, this is a case study suggesting that the generalizations of genetic conservation principles in oceanic islands, such as low levels of genetic diversity, are not always the case. Rather than challenge these principles, we stress that island dynamism throughout time should be an important factor in explaining levels of genetic diversity in insular species. [ABSTRACT FROM AUTHOR]

Brazil stands out at the global level for having implemented several policies intending to promote agroecology as a productive paradigm for small-holder farmers. However, the impacts of this process of institutionalization of agroecology still lack research and debates that evaluate the effectiveness of these policies. In this paper, we assess and discuss the impacts of a policy specifically focused on education in agroecology, the support to the establishment of Centers for the Study of Agroecology and Organic Production (NEAs) in more than 150 higher education institutions throughout Brazil. NEAs bring together teachers, researchers, and students who engage in teaching, research, and extension activities in partnerships with peasant farmers, their organizations, and rural extension workers. The hypothesis that guides our analysis is that this support to establish NEAs allowed redistribution of symbolic power in the universities where they were established, supporting agroecology to gain greater legitimacy inside and outside the university field. Based on an in-depth study of four NEAs, performed through participant observation and documentary analysis, the NEAs are evaluated from the perspective of social fields in dispute, first in a university sphere, but also from the perspective of training people in integrative and transdisciplinary thinking that will contest the industrial-corporate food regime. Our findings suggest that the State support to university groups dedicated to the promotion of agroecology has allowed the construction of what we have named agroecological spaces, which symbolically dispute the dominant paradigms in educational institutions, supporting the constitution of material and immaterial agroecological territories. [ABSTRACT FROM AUTHOR]

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This article aims to analyze the implementation of Agroforestry Systems (AFS) by family farmers, assessing their contribution to agroecological transition and understanding the process of knowledge construction. The study was carried out in family farming farms in the Sumaré Rural Settlement, and in the area of Family Farming and Agroecological Cooperative (Cooperacra), respectively located in the municipalities of Sumaré and Americana, São Paulo State, Brazil. The methodology was based on a case study, using Focal Groups and Field Notes as research instruments. On the basis of our analysis, there were social changes in the farmers' organization and in the decision-making process, as well as in the landscape in the areas of AFS and surroundings, where agroecological principles were also applied to production. In Sumaré, the four farmers participating in the project organized themselves to obtain organic certification. Cooperacra, which works with a group of 10 farmers advanced in the process of agroecological transition, starting from an intensive organic horticulture production system to a biodiverse agroforestry system. Despite the short time of the project, the construction of knowledge in relation to agroforestry systems was perceived through management techniques incorporated by the farmers in their agroecosystems. The arboreal component, which thus far the farmers had seen as something to be eliminated to realize agriculture, was introduced and became a relevant part of the process. The results demonstrate the feasibility and potential of AFS in the process of agroecological transition toward a more sustainable agriculture. [ABSTRACT FROM AUTHOR]

In the last few years, the emergence of a burgeoning middle class in Brazil has transformed the country into one of the fastest growing consumer markets in the world. For MMBB Arquitetos, based in São Paulo, social mobility and the upgrading of urban infrastructure represent a unique opportunity to develop the city. of MMBB describes the practice's strategy for 'urbanising' much needed new infrastructure. A canal with a public park can be inserted, for instance, alongside a new drainage system, providing necessary social adhesion in a fragile urban culture. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

• Cacti represent the most important radiation of succulent angiosperms. • This is the first study using ddRAD-Seq data to follow up hybridization in Cactaceae. • The studied species are highly promiscuous in sympatric areas. • We inferred low genomic introgression and selection favoring parental genotypes. Hybridization and introgression between species in contact/hybrid zones provide important insight into the genetic and ecological mechanisms of speciation. Cactaceae represents the most important radiation of true succulent angiosperms in the New World. This diversification continues to date, with species experiencing few intrinsic barriers to gene flow and the frequent occurrence of natural hybridization. Here, we used RAD-Seq single-nucleotide polymorphism (SNP) data to investigate the genetic architecture of hybridization in four hybrid zones hosting Melocactus concinnus and four congeneric species (M. ernestii, M. glaucescens, M. paucispinus, and M. zehntneri). Our results revealed that M. concinnus is highly promiscuous in sympatric areas and hybridizes with various species distributed in Morro do Chapéu (Diamantina Plateau, Bahia), eastern Brazil. However, the contemporary genomic introgression among the investigated species is very low (c. 2–5%), confirming that even in the face of hybridization, Melocactus species maintain their genetic integrity. The genomic cline approach showed a large fraction of loci deviating from a model of neutral introgression, where most of the loci are consistent with selection favoring parental genotypes. Our results suggest the occurrence of weak premating but strong postmating reproductive isolation in the analyzed cactus species. Furthermore, as most of the Melocactus species are restricted in distribution, hybridization might negatively affect their integrity if hybrids replace the parental species. [ABSTRACT FROM AUTHOR]

Here we use population genomic data (ddRAD-Seq) and ecological niche modeling to test biogeographic hypotheses for the divergence of the island-endemic cactus species Cereus insularis Hemsl. (Cereeae; Cactaceae) from its sister species C. fernambucensis Lem. The Cereus insularis grows in the Fernando de Noronha Islands (FNI), a Neotropical archipelago located 350 km off the Brazilian Atlantic Forest (BAF) coast. Phylogeographic reconstructions support a northward expansion by the common ancestor of C. insularis and C. fernambucensis along the mainland BAF coast, with C. insularis diverging from the widespread mainland taxon C. fernambucensis after colonizing FNI in the late Pleistocene. The morphologically distinct C. insularis is monophyletic and nested within C. fernambucensis, as expected from a progenitor-derivative speciation model. We tested alternative biogeographic and demographic hypotheses for the colonization of the FNI using Approximate Bayesian Computation. We found the greatest support for a stepping-stone path that emerged during periods of decreased sea level (the "bridge" hypothesis), in congruence with historical ecological niche modeling that shows highly suitable habitats on stepping-stone islands during glacial periods. The outlier analyses reveal signatures of selection in C. insularis, suggesting a putative role of adaptation driving rapid anagenic differentiation of this species in FNI., (© 2024. The Author(s), under exclusive licence to The Genetics Society.)

Main Conclusion: Natural selection influenced adaptive divergence between Cereus fernambucensis and Cereus insularis, revealing key genes governing abiotic stress responses and supporting neoteny in C. insularis. Uncovering the molecular mechanisms driving adaptive divergence in traits related to habitat adaptation remains a central challenge. In this study, we focused on the cactus clade, which includes Cereus sericifer F.Ritter, Cereus fernambucensis Lem., and Cereus insularis Hemsley. These allopatric species inhabit distinct relatively drier regions within the Brazilian Atlantic Forest, each facing unique abiotic conditions. We leveraged whole transcriptome data and abiotic variables datasets to explore lineage-specific and environment-specific adaptations in these species. Employing comparative phylogenetic methods, we identified genes under positive selection (PSG) and examined their association with non-synonymous genetic variants and abiotic attributes through a PhyloGWAS approach. Our analysis unveiled signatures of selection in all studied lineages, with C. fernambucensis northern populations and C. insularis showing the most PSGs. These PSGs predominantly govern abiotic stress regulation, encompassing heat tolerance, UV stress response, and soil salinity adaptation. Our exclusive observation of gene expression tied to early developmental stages in C. insularis supports the hypothesis of neoteny in this species. We also identified genes associated with abiotic variables in independent lineages, suggesting their role as environmental filters on genetic diversity. Overall, our findings suggest that natural selection played a pivotal role in the geographic range of these species in response to environmental and biogeographic transitions., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In this study, we have compared 34 repetition units of pBuM-2 satellite DNA of individuals from six isolated populations of Drosophila gouveai, a cactophilic member of Drosophila buzzatii cluster (repleta group). In contrast to the results of previous morphological and molecular data, which suggest differentiation among the D. gouveai populations, the sequences and the cluster analysis of pBuM-2 monomers showed that this repetitive element is highly conserved among the six D. gouveai populations (97.8% similarity), indicating a slow rate of evolution of pBuM-2 sequences at the population level. Probably, some homogenization mechanisms of tandem sequences, such as unequal crossing or gene conversion, have maintained the sequence similarity of pBuM-2 among D. gouveai populations. Alternatively, such a result may be associated with a functional role of pBuM-2 sequences, although it is not understood at present.

Drosophila serido and D. antonietae are sibling species belonging to the Drosophila buzzatii cluster. Morphologically, they can only be discriminated by quantitative traits. In this paper we analyze the length and equalized average curvature of four regions of the aedeagus of D. antonietae and D. serido. Specimens of D. serido and D. antonietae were classified correctly 96.74% of the time. Based only on the variable that most contributed to the discrimination of the groups (equalized average curvature of the arch IV of the aedeagus), we observed significant intraspecific morphological divergence in D. serido in relation to the D. antonietae, in agreement with other markers. The high morphological divergence in equalized average curvature of the arch IV of the aedeagus shows that this region evolved faster than others, since the divergence of the two species. The importance of the present study to the understanding of the genetic basis that controls the formation of the aedeagus, in the species of the Drosophila buzzatii cluster, is discussed.