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1. Humanization of the rpb9 locus in fission yeast reveals conserved and divergent roles of rpb9 and human POLR2I

   https://doi.org/10.64898/2026.04.02.716003  

   Finkel, Jared M; Williams, Micah G; Nirmal, Mamta B; Pandey, Samakshi; Howe, Erik D; Liu, Cameron T; Lohman, Jeremy R; Sharma, Nimisha; Vo, Tommy V (April 2026, bioRxiv)

   Abstract Background/ObjectivesRNA polymerase II is a multifunctional complex that is critical for gene regulation and environmental responses. Its POLR2I subunit in human is associated with various pathologies, including cancer chemoresistance. However, much of our understanding of how POLR2I could function indirectly derives from studies of its homologs in yeasts called Rpb9. Here, we endogenously humanized therpb9gene of the fission yeastSchizosaccharomyces pombeto examine the functional capabilities of POLR2I. MethodsWe edited the genomicrpb9locus inS. pombeso that it encodes the human POLR2I protein, and investigated functional and structural conservation. ResultsWith our humanized yeast system, we find widespread functional complementation by humanPOLR2IofS. pombe rpb9roles in yeast growth, chronological aging, and stress responses. We also find thatPOLR2Icomplements novel roles for yeastrpb9in facultative heterochromatin assembly, resistance against the chemotherapy 5-fluorouracil, and resistance against the fungicide thiabendazole. In contrast, we find thatPOLR2Icannot complement the role ofrpb9in resistance against the transcription elongation inhibitor 6-azauracil (6-AU) in our system. Interestingly,POLR2Icould complement 6-AU resistance if ectopically expressed. Lastly, we observe extensive structural homology between Rpb9 and POLR2I proteins. ConclusionsOur study establishes an endogenous cross-species gene complementation strategy that uncovers both conserved and rewired functions of fission yeastrpb9and its human homolog,POLR2I. In addition to validating conserved roles, we also identified conservation of previously unrecognized roles ofrpb9in heterochromatin formation and chemoresistance. 

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2. Ontogenetic biomechanics of tufted ( Sapajus ) and untufted ( Cebus ) capuchin mandibles

   https://doi.org/10.1002/ajpa.25006  

   Polvadore, Taylor A; Yoakum, Caitlin B; Taylor, Parker M; Holmes, Megan A; Laird, Myra F; Chalk‐Wilayto, Janine; Kanno, Cláudia Misue; de_Oliveira, José Américo; Terhune, Claire E (July 2024, American Journal of Biological Anthropology)

   Abstract ObjectivesCortical bone geometry is commonly used to investigate biomechanical properties of primate mandibles. However, the ontogeny of these properties is less understood. Here we investigate changes in cortical bone cross‐sectional properties throughout capuchin ontogeny and compare captive versus wild, semi‐provisioned groups. Tufted capuchins (Sapajusspp.) are known to consume relatively hard/tough foods, while untufted capuchins (Cebusspp.) exploit less mechanically challenging foods. Previous research indicates dietary differences are present early in development and adultSapajusmandibles can resist higher bending/shear/torsional loads. Materials and methodsThis study utilized microCT scans of 22Cebusand 45Sapajusfrom early infancy to adulthood from three sample populations: one captiveCebus, one captiveSapajus, and one semi‐provisioned, free‐rangingSapajus. Mandibular cross‐sectional properties were calculated at the symphysis, P₃, and M₁. If the tooth had not erupted, its position within the crypt was used. A series of one‐way ANOVAs were performed to assess differences between and within the sample populations. ResultsMandible robusticity increases across ontogeny for all three sample populations.Sapajuswere better able to withstand bending and torsional loading even early in ontogeny, but no difference in shear resistance was found. Semi‐provisioned, free‐rangingSapajustend to show increased abilities to resist bending and torsional loading but not shear loading compared to captiveSapajus. DiscussionThis study helps advance our understanding of the primate masticatory system development and opens the door for further studies into adaptive plasticity in shaping the masticatory apparatus of capuchins and differences in captive versus free‐ranging sample populations. 

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3. Genetic and molecular landscapes of the generalist phytopathogen Botrytis cinerea

   https://doi.org/10.1111/mpp.13404  

   Singh, Ritu; Caseys, Celine; Kliebenstein, Daniel J (January 2024, Molecular Plant Pathology)

   Abstract Botrytis cinereaPers. Fr. (teleomorph:Botryotinia fuckeliana) is a necrotrophic fungal pathogen that attacks a wide range of plants. This updated pathogen profile explores the extensive genetic diversity ofB. cinerea, highlights the progress in genome sequencing, and provides current knowledge of genetic and molecular mechanisms employed by the fungus to attack its hosts. In addition, we also discuss recent innovative strategies to combatB. cinerea. TaxonomyKingdom: Fungi, phylum: Ascomycota, subphylum: Pezizomycotina, class: Leotiomycetes, order: Helotiales, family: Sclerotiniaceae, genus:Botrytis, species:cinerea. Host rangeB. cinereainfects almost all of the plant groups (angiosperms, gymnosperms, pteridophytes, and bryophytes). To date, 1606 plant species have been identified as hosts ofB. cinerea. Genetic diversityThis polyphagous necrotroph has extensive genetic diversity at all population levels shaped by climate, geography, and plant host variation. PathogenicityGenetic architecture of virulence and host specificity is polygenic using multiple weapons to target hosts, including secretory proteins, complex signal transduction pathways, metabolites, and mobile small RNA. Disease control strategiesEfforts to controlB. cinerea, being a high‐diversity generalist pathogen, are complicated. However, integrated disease management strategies that combine cultural practices, chemical and biological controls, and the use of appropriate crop varieties will lessen yield losses. Recently, studies conducted worldwide have explored the potential of small RNA as an efficient and environmentally friendly approach for combating grey mould. However, additional research is necessary, especially on risk assessment and regulatory frameworks, to fully harness the potential of this technology. 

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4. Phylogenetic relationships and the repeated loss of traits associated with sicklebill pollination in Centropogon subgenus Centropogon (Campanulaceae)

   https://doi.org/10.1002/ajb2.70016  

   Mansaray, Janet K; Bedoya, Ana M; Frost, Laura A; Degreenia, Olivia C; Lagomarsino, Laura P (March 2025, American Journal of Botany)

   Abstract PremiseCentropogonsubgenusCentropogoncomprises 55 species found primarily in midelevation Andean forests featuring some of the most curved flowers among angiosperms. Floral curvature is linked to coevolution with the sicklebill hummingbird, which pollinates most species. Despite charismatic flowers, there is limited knowledge about the phylogenetic relationships and floral evolution. MethodsWe conducted the first densely sampled phylogenomic analysis of the clade using methods that account for incomplete lineage sorting on a sequence capture dataset generated with a lineage‐specific probe set. Using phylogenetic comparative methods, we test for correlated evolution of two traits central to sicklebill pollination. ResultsWe improve understanding of species relationships by more than doubling past taxon sampling. We confirm the monophyly of the subgenus and two sections, and the non‐monophyly of remaining sections. The subgenus is characterized by high gene tree discordance. Three widespread species display contrasting phylogenetic dynamics, withC. cornutusforming a clade andC. granulosusandC. solanifoliusforming non‐monophyletic, biogeographically clustered lineages. Correlated evolution of floral curvature and inflorescence structure has led to multiple putative losses of sicklebill pollination. ConclusionsCentropogonsubgenusCentropogonadds to a growing body of literature of Andean plant clades with high gene tree discordance. This phylogeny serves as a foundational framework for further macroevolutionary investigations into the environmental and biogeographic factors shaping the evolution of pollination‐related traits. 

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5. Climatic niche evolution and speciation modes in the transisthmian Alpheus shrimps (Caridea: Alpheidae)

   https://doi.org/10.1111/jbi.14864  

   Alves, Douglas_Fernandes Rodrigues; Martinez, Pablo Ariel; de_Barros‐Alves, Samara_de P; de_Almeida, Ariádine Cristine; Elias, Marco_Aurélio Mendes; Hurt, Carla; Hultgren, Kristin M (October 2024, Journal of Biogeography)

   Abstract AimWe studied the niche evolution and diversification modes in transisthmianAlpheusshrimps by examining the interplay between environmental niche divergence and conservatism in allopatric sister species. In a broader perspective, the current study analysed the evolution of climatic niche and the role of the environment in species diversification ofAlpheustransisthmian shrimp. LocationAtlantic and Eastern‐Pacific oceans. TaxonAlpheusshrimps (Caridea: Alpheidae). MethodsWe assembled georeferenced occurrences for 33 species ofAlpheus(with 24 sister species) from a time‐calibrated molecular phylogeny. We modelled their ecological niches and assessed niche overlap through pairwise comparisons. Additionally, we performed phylogenetic reconstructions of the ancestral environmental niche, for each niche axis. ResultsOur results demonstrate that thermal tolerances, food availability and hydrodynamic forces were relevant environmental axes in evolutionary processes in transisthmian species ofAlpheus. Among the 528 paired comparisons, we found that most niches were divergent, including in 12 clades formed by pairs of sister species (in only two of these clades were the niches fully equivalent). Phylogenetic reconstructions of ancestral niches showed an initial niche conservatism in all axes, with divergences intensifying in the last 12 million years. Main ConclusionsWe found evidence that confirms the relevance of the environmental changes that occurred in the West Atlantic and East Pacific for niche evolution in transisthmianAlpheusspecies, as well as for the emergence of some lineages. Our findings provide evidence for different modes ofAlpheusspecies speciation in a period consistent with the closure of the Isthmus of Panama. 

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