ERECTA (ER) receptor-like kinase (RLK) regulates Arabidopsis thaliana organ growth, and inflorescence and stomatal development by interacting with the ER family (ERf) paralogs, ER-like 1 (ERL1) and ERL2, and the receptor-like protein (RLP) TOO MANY MOUTHS (TMM). ER also controls immune responses and resistance to pathogens such as the bacterium Pseudomonas syringae pv. tomato DC3000 (Pto) and the necrotrophic fungus Plectosphaerella cucumerina BMM (PcBMM). We found that er null-mutant plants overexpressing an ER dominant-negative version lacking the cytoplasmic kinase domain (ERΔK) showed an enhanced susceptibility to PcBMM, suggesting that ERΔK associates and forms inactive complexes with additional RLKs/RLPs required for PcBMM resistance. Genetic analyses demonstrated that ER acts in a combinatorial specific manner with ERL1, ERL2 and TMM to control PcBMM resistance. Moreover, BAK1 (BRASSINOSTEROID INSENSITIVE 1–associated kinase 1) RLK, which together with ERf/TMM regulates stomatal patterning and resistance to Pto, was also found to have an unequal contribution with ER in regulating immune responses and resistance to PcBMM. Co-immunoprecipitation experiments in Nicotiana benthamiana further demonstrated BAK1-ER protein interaction. The secreted Epidermal Pattern Factor peptides (EPF1 and EPF2), which are perceived by ERf members to specify stomatal patterning, do not seem to regulate ER-mediated immunity to PcBMM, since their inducible overexpression in Arabidopsis thaliana did not impact on PcBMM resistance. Our results indicate that the multiproteic receptorsome formed by ERf, TMM and BAK1 modulates Arabidopsis thaliana resistance to PcBMM, and suggest that the cues underlying ERf/TMM/BAK1-mediated immune responses are distinct from those regulating stomatal pattering.

Autophagy is a fast-moving field with an enormous impact on human health and disease. Understanding the complexity of the mechanism and regulation of this process often benefits from the use of simple experimental models such as the social amoeba Dictyostelium discoideum. Since the publication of the first review describing the potential of D. discoideum in autophagy, significant advances have been made that demonstrate both the experimental advantages and interest in using this model. Since our previous review, research in D. discoideum has shed light on the mechanisms that regulate autophagosome formation and contributed significantly to the study of autophagy-related pathologies. Here, we review these advances, as well as the current techniques to monitor autophagy in D. discoideum. The comprehensive bioinformatics search of autophagic proteins that was a substantial part of the previous review has not been revisited here except for those aspects that challenged previous predictions such as the composition of the Atg1 complex. In recent years our understanding of, and ability to investigate, autophagy in D. discoideum has evolved significantly and will surely enable and accelerate future research using this model.

Exposure to air pollutants has a direct impact on human health, resulting in increased mortality rates. Airborne particulate matter (PM) has major adverse effects on health and can be classified as high-risk respiratory particles (fine/PM_2.5, aerodynamic diameter < 2.5 µm) or thoracic particles (coarse/PM₁₀, aerodynamic diameter < 10 µm). In addition, airborne PM can carry microbial communities that alter the commensal microbiota and lead to dysbiosis. Our aim was to synthesize the current research evidence describing the association between air pollution exposure and the microbiome composition of the upper respiratory tract (URT) of the adult population. In this work, a systematic search of the PubMed, EMBASE and Scopus databases was conducted. A total of 9 studies published from 2018 to 2023 were included. 66.5% of the participants were exposed to PM_2.5 concentrations higher than 40 µg/m³, and data showed that PM_2.5 atmospheric levels were positively correlated with PM₁₀ (r_s = 0.95, p < 0.001). All the reviewed studies performed 16S rRNA sequencing of the V3–V4 region from URT samples, using different methods. Overall, evidence of URT microbiome alterations after high PM exposure was observed, with seasonal and geographical influence. Discordant findings were found about bacterial diversity, with a predominant decrease after exposure to high PM levels. Regarding microbiome composition, the relative abundance of the Actinobacteria phylum declined following exposure to high levels of PM, but that of Bacteroidetes and Fusobacteria increased. The studies showed a low-middle risk of bias due to heterogeneity regarding sample processing, sequencing methods, and confounder control. To confirm the observed evidence of an association between PM levels and alterations in the URT microbiome, we strongly recommend that future research work be conducted in accordance with standard guidelines for reporting microbiome studies. In summary, the entry of fine and coarse particles into the URT is associated with microbial dysbiosis, increasing the risk of developing respiratory diseases and allergies. Prospero registration: This systematic review was registered on PROSPERO (#CRD42023416230) Graphical Abstract

Exposure of monolayer Dictyostelium cells to the signalling polyketide DIF-1 causes DimB, a bZIPtranscription factor, to accumulate in the nucleus where it induces prestalk gene expression. Here we analyse DimB signalling during normal development. In slugs DimB is specifically nuclear enriched in the pstB cells; a cluster of vital dye-staining cells located on the ventral surface of the posterior, prespore region. PstB cells move at culmination, to form the lower cup and the outer basal disc of the fruiting body, and DimB retains a high nuclear concentration in both these tissues. In a dimB null (dimB-) strain there are very few pstB or lower cup cells, as detected by neutral red staining, and it is known that the outer basal disc is absent or much reduced. In the dimB- strain ecmB, a marker of pstB differentiation, is not DIF inducible. Furthermore, ChIP analysis shows that DimB binds to the ecmB promoter in DIF-induced cells. These results suggest that the differentiation of pstB cells is caused by a high perceived level of DIF-1 signalling, leading to nuclear localization of DimB and direct activation of cell type-specific gene expression.

Leukemia is the most common childhood cancer and its etiology could be related to various environmental contaminants such as particulate matter (PM). The objective of our study is to evaluate the potential association between exposure to PM during pregnancy and the incidence of childhood leukemia. We established a population-based nationwide cohort using the Spanish Birth Registry Statistics database of the National Statistics Institute. We used spatiotemporal land use random forest models to estimate the concentrations of PM₁₀ and PM_2.5 for the entire pregnancy and by trimesters. We conducted logistic regression analyses adjusted for various covariates. In addition, we fitted generalized additive models (GAMs) to estimate the non-linear relationship between PM levels and leukemia incidence. The study included 3,112,123 children and 1066 cases of leukemia. The results for the continuous variable of PM₁₀ exposure levels suggested an increased risk of childhood leukemia to be associated with higher exposure. The results for the categorized PM₁₀ variable suggest an increased risk of childhood leukemia among pregnant women whose exposure levels were higher than the median (third and fourth quartiles). The results for PM_2.5 were weaker. We found association between exposure to PM₁₀ during pregnancy and an increased risk of childhood leukemia. Our findings indicate that public health interventions should aim to reduce air pollution to lower the incidence of childhood leukemia.