Biology subjects

Dal'Sasso, T. C. S.

Publications and source records attributed to Dal'Sasso, T. C. S..

5 recordsLinked to original sources

bioRxiv2026

Conserved protein folds underpin the diversification of secreted proteins in a fungal pathogen

BACKGROUNDDuring host colonization, fungal plant pathogens secrete effector-like proteins that alter host cell physiology and target plant-associated microbes. However, rapid evolution and low sequence conservation hinder the study and characterization of these proteins. The fungus Zymoseptoria passerinii infects Hordeum spp. and includes lineages adapted to wild and domesticated barley. To date, the evolution of effector-like proteins in this species has not been addressed. RESULTSWe combined a set of protein structure-based and network analyses to unravel the secretome of Z. passerinii. We first compared AlphaFold2 and ESMFold predictions to establish the baseline for structural analyses. We identified 72 structural clusters in the secretome, revealing fold-level relationships across divergent sequences. We showed that effector-like proteins with host putative immune-interfering functions evolved from a limited group of protein folds, whereas proteins with predicted antimicrobial properties were distributed across fold groups. Physicochemical comparisons indicate that antimicrobial effectors predominantly emerged through amino acid replacements on common effector-enriched scaffolds in Z. passerinii, reconfiguring surface charge and electrostatics. We analyzed intra- and interspecific structural variation in selected effector-enriched families by comparing Z. passerinii proteins and homologs in the sister species Z. tritici. We describe high structural similarity in core folds, with local variation in loop and surface-exposed regions, consistent with fold stability still enabling functional diversification. CONCLUSIONSThe secretome of Z. passerinii is organized around common structural folds that support diverse biological roles, including host manipulation and host-associated microbial interactions. Conserved scaffolds combined with local physicochemical variation likely contribute to rapid adaptive evolution in Z. passerinii.

genomics↗

bioRxiv2025

Host-specific fungal plant pathogens exhibit distinct interactions with the leaf microbiota of wild grasses

The plants microbiome is influenced by the plant species and biotic factors such as the infection by pathogens. Pathogen-microbiome interactions are relevant for the progression of the disease since both can compete within the plant host. We hypothesize that pathogens specialized to different hosts have distinct, direct, and indirect influence on the host microbiome. We focused on the host-specific leaf pathogens Zymoseptoria tritici and Zymoseptoria passerinii. By using microbiome metabarcoding and coculture interactions, we evaluated the influence of virulent (wild host-infecting pathogen) and avirulent (domesticated host-infecting pathogen) Zymoseptoria lineages on the leaf microbiome of the wild grasses Aegilops cylindrica and Hordeum murinum which are hosts to virulent lineages of Z. tritici and Z. passerinii, respectively. Our microbiome analysis showed that the fungal communities were affected by virulent lineages, while the avirulent lineages had the most negative correlations with bacteria. Both virulent and avirulent pathogens had the same spectrum of interactions when experimentally cocultured with bacteria. The intensity of pathogen-induced growth enhancement differed between Zymoseptoria lineages. We demonstrated that sugar metabolism through the fungal secretion of invertase can be a determinant of bacterial growth enhancement. Our study highlights the role of microbial interactions on host-specificity and mechanisms underlying microbial interactions by Zymoseptoria spp.

microbiology↗

bioRxiv2023

FROM FOREST TO SAVANNA AND BACK TO FOREST: EVOLUTIONARY HISTORY OF THE GENUS Dimorphandra (LEGUMINOSAE)

The tree genus Dimorphandra comprises 26 species, which are circumscribed into three subgenera. The subgenus Dimorphandra is associated with both rainforests (Amazon and Atlantic Forest) and savanna-like vegetation (Cerrado); whereas the subgenera Pocillum and Phaneropsia are restricted to the Amazon. We obtained DNA sequence data from six gene regions of the chloroplast genome (cpDNA) and the nuclear internal transcribed spacer (ITS) from 17 species of Dimorphandra and 12 closely related species. Bayesian phylogeny and haplotype network analyses together with both ancestral area reconstructions and ecological niche modeling allowed for exploring the late evolutionary history of the genus Dimorphandra. Species within the subgenus Phaneropsia were more closely related to species of the genus Mora than to the remaining congeners in the plastid tree (but not in the ITS tree), casting doubts on the monophyly of Dimorphandra. Such incongruence may be the result of incomplete lineage sorting of ancient polymorphisms. Amazonian lineages (subgenera Pocillum and Phaneropsia) were highly polymorphic and divergent; whereas lineages from either the Cerrado or the Atlantic Forest were genetically depauperate. The Amazon seems to be the likely source of the lineage that gave rise to the extant species of Dimorphandra of the Cerrado. In turn, a lineage that occupied the Cerrado likely gave rise to the extant species that occur in the Atlantic Forest. Habitat shifts may have been a key driving force that shaped the late evolutionary history of Dimorphandra.

evolutionary biology↗

bioRxiv2022

The Necrosis- and Ethylene-inducing peptide 1-like protein (NLP) gene family of the plant pathogen Corynespora cassiicola

Effectors are secreted by plant-associated microorganisms in order to modify the host cell physiology. As effectors, the Necrosis- and Ethylene-inducing peptide 1-like proteins (NLPs) are involded in the early phases of plant infection and may trigger host immune responses. Corynespora cassiicola is a polyphagous plant-pathogen that causes target spot on many agriculturally important crops. Using genome assembly, gene prediction, and proteome annotation tools, we retrieved 135 NLP-encoding genes from proteomes of 44 isolates. We explored the evolutionary history of NLPs using Bayesian phylogeny, gene genealogies, and selection analyses. We accessed the expression profiles of the NLP genes during the early phase of C. cassiicola-soybean interaction. Three NLP effector genes (Cc_NLP1.1, Cc_NLP1.2A, and Cc_NLP1.2B) were maintained in the genomes of all isolates tested. A non-effector NLP gene (Cc_NLP1.3) was found in three isolates that had been originally obtained from soybean. NLP effectors were under different selective constraints: Cc_NLP1.1 was under stronger selective pressure, while Cc_NLP1.2A was under a more relaxed constraint. Meanwhile, Cc_NLP1.2B likely evolved under either positive or balancing selection. Despite highly divergent, the effector NLPs maintain conserved the residues necessary to trigger plant immune responses, suggesting they are potentially functional. Only the Cc_NLP1.1 effector gene was significantly expressed at the early hours of soybean colonization, while Cc_NLP1.2A and Cc_NLP1.2B showed much lower levels of gene expression.

microbiology↗

bioRxiv2022

Genome-wide analysis and evolutionary history of the Necrosis and Ethylene-inducing peptide 1-like protein (NLP) superfamily across the Dothideomycetes class of fungi

Necrosis and Ethylene-inducing peptide 1-like proteins (NLPs) are broadly distributed across bacteria, fungi and oomycetes. Cytotoxic NLPs are usually secreted into the host apoplast where they can induce cell death and trigger plant immune responses in eudicots. To investigate the evolutionary history of the NLPs, we accessed the genomic resources of 79 species from 15 orders of Dothideomycetes. Phylogenetic approaches searched for biased patterns of NLP gene evolution and aimed to provide a phylogenetic framework for the cytotoxic activities of NLPs. Among Dothideomycetes, the NLP superfamily sizes varied, but usually contained from one to six members. Superfamily sizes were higher among pathogenic fungi, with family members that were mostly effector NLPs. Across species, members of the NLP1 family (Type I NLPs) were predominant (84%) over members of the NLP2 family (Type II NLPs). The NLP1 family split into two subfamilies (NLP1.1 and NLP1.2). The NLP1.1 subfamily was broadly distributed across Dothideomycetes. There was strong agreement between the phylogenomics of Dothideomycetes and the phylogenetic tree based on members of the NLP1 subfamilies. To a lesser extent, phylogenomics also agreed with the phylogeny based on members of the NLP2 family. While gene losses seem to have shaped the evolutionary history of NLP2 family, ancient gene duplications followed by descent with modification characterized the NLP1 family. The strongest cytotoxic activities were recorded on NLPs of the NLP1.1 subfamily, suggesting that biased NLP gene retention in this subfamily favored the cytotoxic paralogs.

evolutionary biology↗