Jonathan Javier Mucherino Muñoz

Croton urucurana is a pioneer species used in soil regeneration and traditional medicine. Despite expectations of adaptive variation across its extensive range, the species’ macro-geographic genetic structure and its relationship with phenotypic traits are still poorly understood. To address this knowledge gap and identify critical evolutionary reservoirs, this study integrated molecular, anatomical, and palynological data to evaluate diversity across the Chaco , Amazon, Cerrado , and Atlantic Forest domains. Twenty-nine specimens were analyzed using Light and Scanning Electron Microscopy, in parallel to DNA analysis, to assess genetic structure. The study identified two distinct genetic lineages. Brazil exhibited the highest genetic diversity, containing representatives of both lineages. Argentina showed the lowest diversity, composed almost exclusively of a single lineage, whereas Paraguayan samples are distributed between two groups, consistent with a zone of genetic contact and admixture. Molecular variance analysis shows that 94% of genetic variation exists within populations, indicating strong local genetic diversity. Meanwhile, differentiation among countries is low, despite two historical genetic lineages. Pollen remained highly conserved across all populations, suggesting low intraspecific plasticity, while leaf anatomy exhibited phenotypic plasticity. However, these micromorphological variations did not correlate with the two lineages. The results suggest that the genetic structure of C. urucurana is driven by two historical lineages. Brazilian and Paraguayan populations are critical genetic reservoirs and should be prioritized for conservation. The lower variability in Argentina suggests higher vulnerability to environmental shifts. Preserving these lineages is essential for maintaining the species’ evolutionary potential and its pharmacological properties.

Aedes aegypti, a critical vector for tropical diseases, poses significant challenges for studying its embryogenesis due to difficulties in removing its rigid chorion and achieving effective fixation for in situ hybridization. Here, we present novel methodologies for fixation, dechorionation, DAPI staining, and in situ hybridization, enabling the detailed analysis of gene expression throughout Ae. aegypti embryogenesis. By synchronizing eggs at various developmental stages (0–72 h), we localized the transcripts of the gap gene mille‐pattes (mlpt), the dorsoventral gene cactus (cact), and the pioneer transcription factor (pTF) zelda (zld). In situ hybridization and RT‐qPCR analyses revealed that mlpt and cact are maternally expressed, while zld expression begins zygotically during cellularization and later becomes prominent in neuroblasts. Analysis of previously published transcriptomes suggests that three other pTFs, CLAMP, grainyhead, and GAF, are also maternally expressed and may function as pioneer transcription factors during Ae. aegypti embryogenesis. These findings suggest that the transcription factors responsible for genome activation in mosquitoes differ from those in fruit flies, highlighting significant divergence in the genetic regulation of early Dipteran embryogenesis.

Dalbergia nigra is a long-living tree endemic to the Atlantic Rain Forest. Due to its high commercial value, this species has been widely exploited for timber production and is now endangered. It is widely known that understanding patterns of genetic structure is paramount for conserving threatened species. We analyzed the genetic diversity of 140 individuals from four different forest fragments in the southern region of Bahia, Brazil, to verify the possible effects of fragmentation on these populations and provide information for conservation initiatives. High polymorphism levels were detected from the genotyping of nine microsatellite loci (mean H_E = 0.733). All populations showed high genetic diversity; however, a reduction of genetic diversity was detected in each population (H_O < H_E). The average fixation index was high and significant (f = 0.167), which could be due to the occurrence of inbreeding, the Wahlund effect, reproductive system, or from null alleles. Genetic differentiation among populations was high (mean θ_P = 0.118), suggesting strong isolation, a pattern consistent with historically low gene flow. The Bayesian analysis revealed five different genetic groups, among which three groups correspond to three different forest fragments, and two groups showed the genetic subdivision of individuals from the other forest fragment. Based on our results, the suggested conservation strategy for D. nigra populations in the southern region of Bahia, Brazil, involves high environmental investments to protect all sampled forest fragments and individuals. Another strategy would be to collect seeds from all individuals from the sampled fragments and start a new population with human interference in its evolutive history inside a protection unit.

Black pod disease, caused by Phytophthora spp., is one of the main diseases that attack cocoa plantations. This study validated, by association mapping, 29 SSR molecular markers flanking to QTL (Quantitative Trait Loci) associated with Phytophthora palmivora Butler (Butler) (PP) resistance, in three local ancient varieties of the Bahia (Comum, Pará, and Maranhão), varieties that have a high potential in the production of gourmet chocolate. Four SSR loci associated with resistance to PP were detected, two on chromosome 8, explaining 7.43% and 3.72% of the Phenotypic Variation (%PV), one on chromosome 2 explaining 2.71%PV and one on chromosome 3 explaining 1.93%PV. A functional domains-based annotation was carried out, in two Theobroma cacao (CRIOLLO and MATINA) reference genomes, of 20 QTL regions associated with cocoa resistance to the pathogen. It was identified 164 (genome CRIOLLO) and 160 (genome MATINA) candidate genes, hypothetically involved in the recognition and activation of responses in the interaction with the pathogen. Genomic regions rich in genes with Coiled-coils (CC), nucleotide binding sites (NBS) and Leucine-rich repeat (LRR) domains were identified on chromosomes 1, 3, 6, 8, and 10, likewise, regions rich in Receptor-like Kinase domain (RLK) and Ginkbilobin2 (GNK2) domains were identified in chromosomes 4 and 6.