Biology subjects

Fantino, E. I.

Publications and source records attributed to Fantino, E. I..

4 recordsLinked to original sources

bioRxiv2026

A horizontally acquired and recurrently expanded glycoside hydrolase subfamily across leafhoppers

Horizontal gene transfer from bacteria is a known source of metabolic novelty in insects, yet how these acquisitions diversify and persist over evolutionary time scales remains poorly understood. Here, we reconstructed the evolutionary history of the bacterial glycoside hydrolase subfamily GH5-40 across leafhoppers (Cicadellidae). We annotated 24 genomes and identified 87 GH5-40 genes encoding 113 catalytic domains across 23 leafhopper species, with copy numbers ranging from 1 to 19 genes per genome. Maximum-likelihood phylogenetic analyses recovered all leafhopper GH5-40 domains as a single clade nested within Actinobacteria, supporting one ancestral acquisition followed by extensive lineage-specific duplication of both genes and catalytic domains. Seventeen genes encode 2 to 4 tandem catalytic domains connected by disordered linkers, and a four-domain architecture recurs independently in two divergent leafhopper subfamilies. Recombinant enzymes from distantly related species displayed contrasting substrate preferences for {beta}-glucans and {beta}-mannans in vitro, despite GH5-40 enzymes being classically characterized as endo-{beta}-1,4-mannanases.

evolutionary biology↗

bioRxiv2026

RenSeq and whole genome sequencing uncover allelic diversity of clubroot resistance genes in commercial breeding canola lines

Clubroot disease, caused by the obligate biotrophic pathogen Plasmodiophora brassicae, is a major threat to canola (Brassica napus) production worldwide. Clubroot-resistant (CR) cultivars remain the most effective disease-management strategy, but the genetic basis of resistance in commercial canola remains poorly understood because many resistance sources are proprietary and associated genotypic information is rarely accessible. Although nucleotide-binding leucine-rich repeat (NLR) immune receptors account for most cloned CR genes, no pan-NLRome has incorporated CR lines used in commercial canola breeding. Here, we combined whole-genome sequencing and resistance gene enrichment sequencing (RenSeq) to assemble and annotate the NLR repertoires of five homozygous CR inbred lines (IH1-IH5) used for commercial breeding and displaying contrasting resistance profiles against predominant Canadian P. brassicae pathotypes. We integrated these NLRomes with the susceptible cultivar Westar to construct a comparative pan-NLRome for canola. Across the five CR lines, total NLR content was highly conserved, ranging from 504 to 517 genes, with TIR-NLRs representing the predominant class. C-JID-containing TIR-NLRs accounted for more than 30% of each NLR repertoire, and integrated-domain analysis identified conserved and genotype-specific NLR-IDs, including previously unreported domains in IH4. Pan-NLRome analysis resolved 366 NLR orthogroups (OGs), 60.7% of which were core, and identified resistant-line-enriched OGs absent from Westar as candidate CR-associated loci. Unexpectedly, a homolog of the functionally characterized CR gene, CRa, was detected in five CR lines. Moreover, a homolog of another CR gene, Crr1a, was detected in both resistant and susceptible lines, indicating that the presence/absence of a gene alone does not predict resistance. Instead, structural variation affecting LRR and C-JID regions suggests that allele-level diversity within conserved NLR loci contributes to CR-associated variation, with implications for allele-specific marker development and durable CR deployment.

plant biology↗

bioRxiv2026

A clubroot pathogen PBS3-like effector manipulates hormonal crosstalk to alter root morphology during colonization

O_LISalicylic acid (SA) and auxin are key regulators of plant immunity and development. The clubroot pathogen Plasmodiophora brassicae encodes PbGH3, an effector related to the GH3 family involved in phytohormone homeostasis. Although PbGH3 was proposed to conjugate auxin in vitro, its biological function in planta has remained unclear. This study aimed to determine the in vivo role of PbGH3 during host colonization. C_LIO_LIWe generated Arabidopsis thaliana and Brassica napus lines overexpressing PbGH3 and characterized their developmental phenotypes, hormone profiles, gene expression, and susceptibility to infection. Structural modeling was performed to assess PbGH3 similarity to plant GH3 proteins, and functional complementation was tested using the Arabidopsis gh3.12 mutant. C_LIO_LIThe expression of PbGH3 in Arabidopsis induced auxin-related developmental phenotypes without detectable accumulation of auxin conjugates. Instead, PbGH3 structurally and functionally resembled GH3.12/PBS3 inducing increased conjugated SA levels, reduced jasmonic acid, suppressed PIN2 expression, and increased root hair number and infection. PbGH3 complemented SA-related defects in the gh3.12 mutant. C_LIO_LIPbGH3 functions as a modulator of SA metabolism rather than an auxin-conjugating enzyme, likely competing with host GH3.12/PBS3 to constrain effective SA accumulation. This reveals a novel strategy by which P. brassicae disrupts SA-auxin homeostasis to promote host colonization and ensure disease development. C_LI PLAIN LANGUAGE SUMMARYThis study shows that the clubroot pathogen uses a protein called PbGH3 to modify the plants salicylic acid balance. This alters root traits and increases susceptibility to infection. Arabidopsis and canola plants engineered to produce PbGH3 showed similar changes, revealing that the pathogen uses this protein to disrupt hormone regulation and create conditions that support its colonization.

plant biology↗

bioRxiv2025

Pectobacterium sinaloense sp. nov., a novel phytopathogenic species isolated from potato plants in Mexico

As part of a broader effort to survey and characterize the diversity of pectolytic bacteria affecting potato crops in Mexico, phytopathogenic strains were isolated from soft rot symptoms in potato plants in Sinaloa. Among them, an atypical Pectobacterium-like strain, LFLA-215T, could not be confidently assigned to any known species through biochemical or molecular methods. To clarify its taxonomic position and explore its genomic and functional features, whole-genome sequencing and comparative analyses were conducted, accompanied by biochemical, morphological and pathogenicity evaluations. The strain LFLA-215T is Gram-stain-negative, with peritrichous flagella, catalase-positive, and oxidase-negative. Phylogenetic analyses based on the 16S rRNA operon, dnaJ, and 923 core genes, confirmed that strain LFLA-215T belongs to the genus Pectobacterium. However, genomic similarity values with other Pectobacterium species, ranging from 87.73-93.53% (ANIb), 87.63-93.46% (ANIu), and 34.0-52.1% (isDDH), fell below species delineation thresholds. Pectobacterium colocasium LJ1T showed the closest relationship to LFLA-215T, whereas Pectobacterium parmentieri RNS 08-42-1AT was the most distantly related. Although LFLA-215T fulfilled Kochs postulates and demonstrated pathogenicity in potato plants, its virulence on tubers was comparatively lower than that of other known Pectobacterium strains, which could be related to the size and the reduction of the total number of genes when analyzed its complete genome reported here. Taken all together, our findings support the classification of strain LFLA-215T as a novel species within the genus Pectobacterium, for which the name Pectobacterium sinaloense sp. nov. is proposed, with LFLA-215T designated as the type strain.

microbiology↗