Biology subjects

Camborde, L.

Publications and source records attributed to Camborde, L..

3 recordsLinked to original sources

bioRxiv2026

The root knot nematode effector MiEFF186 interacts with a splicing factor to reshape plant transcriptome

The root-knot nematode Meloidogyne incognita secretes specific effectors to manipulate root cells and induce their redifferentiation into multinucleate feeding giant cells, which are essential for its development. A dedicated screen identified the M. incognita MiEFF186a effector as a regulator of alternative splicing, a crucial mechanism of transcriptional gene regulation whereby a single gene can produce multiple mature mRNA variants, in plants. EFF186 is expressed in the esophageal glands of nematode juveniles, and in planta, it localizes to the nucleus and accumulates in the nucleolus. A yeast two-hybrid approach identified the nucleolar G-patch protein GDP1/CIS2 as a MiEFF186a target in tomato and Arabidopsis. Transcriptomic analyses of Arabidopsis roots ectopically expressing MiEFF186a or impaired in GDP1/CIS2 function revealed changes in both gene expression and alternative splicing, with partially overlapping responses. Finally, alteration of GDP1/CIS2 expression by virus-induced gene silencing in Solanaceae or in Arabidopsis gdp1 mutants affects susceptibility to M. incognita. Together, these results identify GDP1/CIS2 as a host target of MiEFF186a and support a role for these proteins in the modulation of host RNA metabolism during nematode parasitism.

plant biology↗

bioRxiv2026

A root pathogen drives rhizosphere enrichment of antagonistic Pseudomonas and induces production of an antimicrobial metabolite

In plants, the development of soil-borne diseases has been shown to trigger the recruitment of beneficial microbes, which contribute to defense against pathogens. However, the underlying mechanisms driving this recruitment remain elusive. Here, we used a gnotobiotic system combined with a synthetic bacterial community (SynCom) derived from the Medicago truncatula rhizosphere to dissect microbiota pathogen interaction and its role in the development of root rot caused by Aphanomyces euteiches, a devastating soilborne oomycete pathogen of legumes. Through integrated metabarcoding, metabolomics and transcriptomics, we reveal that pathogen infection restructures the bacterial SynCom, selectively enriching the microbial community with specific Pseudomonas spp. strains displaying anti A. euteiches activity. This shift alleviates root rot symptoms, triggers the biosynthesis of the antibiotic 2,4-diacetylphloroglucinol (DAPG), a Pseudomonas specialized metabolite inhibiting A. euteiches growth, and amplifies the plant endogenous isoflavonoid defense responses. Unexpectedly, we found that A. euteiches directly activates DAPG production in beneficial bacteria independently of the plant, through the production of a heat-stable, high-molecular-weight (30 - 100 kDa) extracellular components. These findings uncover a novel mechanism whereby a pathogen inadvertently activates antibiotic production in beneficial bacteria, extending the plant immune system. Our research underscores the critical role of microbial interactions in the rhizosphere in determining root disease outcomes, paving the way for microbiome-based strategies to combat root diseases.

plant biology↗

bioRxiv2020

A DEAD BOX RNA helicase from Medicago truncatula is hijacked by an RNA-binding effector from the root pathogen Aphanomyces euteiches to facilitate host infection

Microbial effectors from plant pathogens are molecules that target host components to facilitate colonization. While eukaryotic pathogens are virtually able to produce hundreds of effectors, the molecular mechanisms allowing effectors to promote infection are still largely unexplored. Here we show that the effector AeSSP1256 from the soilborne oomycete pathogen Aphanomyces euteiches is able to interact with plant RNA. Heterologous expression of AeSSP1256 delays Medicago truncatula host roots development and facilitate pathogen colonization. Transcriptomic analyses of AeSSP1256-expressing roots show a downregulation of genes implicated in ribosome biogenesis pathway. A yeast-two hybrid approach reveals that AeSSP1256 associates with a nucleolar L7 ribosomal protein and a M. truncatula RNA helicase (MtRH10) orthologous to the Arabidopsis RNA helicase RH10. Association of AeSSP1256 with MtRH10 impaired the capacity of MtRH10 to bind nucleic acids. Promoter:GUS composite plants revealed that MtRH10 is expressed preferentially in the meristematic root cells. Missense MtRH10 plants displayed shorter roots with developmental delay and are more susceptible to A. euteiches infection. These results show that the effector AeSSP1256 facilitates pathogen infection by causing stress on plant ribosome biogenesis and by hijacking a host RNA helicase involved in root development and resistance to root pathogens.

plant biology↗