Biology subjects

De Coninck, B.

Publications and source records attributed to De Coninck, B..

4 recordsLinked to original sources

bioRxiv2026

Soil-based disease bioassay for the study of rhizogenic Agrobacterium-tomato interactions

2.Hairy root disease (HRD), caused by rhizogenic Agrobacterium, is an economically important disease affecting hydroponic tomato (Solanum lycopersicum L.) production worldwide. HRD-affected plants show extensive root proliferation, resulting in decreased energy expenditure towards fruit production. Host plant susceptibility to rhizogenic Agrobacterium is typically evaluated through artificial wounding-based infection bioassays. However, under natural infection settings, rhizogenic Agrobacterium can induce disease symptoms without deliberate, artificial wounding. We developed a soil-based, non-wounding bioassay that closely mimics natural rhizosphere interactions and permits quantitative and qualitative assessment of HRD symptoms. The assay measured root dry weight, documented agravitropic root development typical of HRD and confirmed in planta T-DNA gene expression using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). We used this bioassay to evaluate disease symptoms towards rhizogenic Agrobacterium in tomato cv. Moneymaker and the rootstocks Optifort, Maxifort, and Arnold. Optifort and Maxifort exhibited significantly higher root biomass than Arnold and Moneymaker, indicating more pronounced symptom development. The bioassay also differentiated virulence levels amongst various rhizogenic Agrobacterium strains isolated from HRD-affected plants. Together, these results show that our soil-based bioassay provides a robust and ecologically relevant platform for screening tomato genotypes and comparing virulence levels of rhizogenic Agrobacterium strains supporting resistance breeding and disease management efforts.

plant biology↗

bioRxiv2025

Nuclear SnRK1 activity delays clubroot development in Arabidopsis by reducing sink strength

Clubroot, caused by the soil-borne protist Plasmodiophora brassicae, is a major disease of Brassica crops, resulting in severe root malformations and yield losses. While most research has centered on immune signaling and hormone dynamics, plant-pathogen interactions also dramatically reshape primary metabolism, often modifying source activity and converting infecting tissues into strong metabolic sinks. The SnRK1 (SNF1-related kinase 1) protein kinase acts as a cellular fuel gauge in plants, integrating metabolic status and environmental and developmental cues to maintain carbon and energy homeostasis. Here, we explored SnRK1-mediated quantitative resistance against clubroot disease in the related crucifer model Arabidopsis thaliana. Both soil and hydroponic-based disease bioassays revealed how especially increased nuclear SnRK11 activity antagonizes clubroot development, suggesting a pivotal role for transcriptional regulation. qRT-PCR analysis and quantification of soluble sugar contents and invertase activity in roots indicate that SnRK1 represses sucrose transporter expression as well as cell wall invertase (CWINV) expression and activity, likely limiting clubroot development by reducing sink strength. Consistently, cellular assays indicate that the recently identified SnRK11-targeting P. brassicae effector PBZF1 interferes with SnRK11 nuclear translocation. Our study thus corroborates that SnRK1 is a primary effector target and shows that SnRK1-mediated reprogramming of gene expression and sink activity is an effective mechanism against clubroot disease development.

plant biology↗

bioRxiv2024

1-Aminocyclopropane-1-carboxylic acid oxidase determines the fate of ethylene biosynthesis in a tissue-specific way to fine-tune development and stress resilience

Ethylene is involved in several developmental processes and responses towards (a)biotic stress. In seed plants, ethylene is produced from its precursor 1-aminocyclopropane-1-carboxylic acid (ACC) by the enzyme ACC-oxidase (ACO). Despite its key role in ethylene synthesis, the ACO gene family has not yet been fully characterized. We investigated the five ACO members of Arabidopsis thaliana and revealed a tissue-and developmentally specific expression pattern. Furthermore, the five ACO enzymes each have a different capacity to produce ethylene. Combined, this allows for a precise spatial and temporal regulation of ethylene synthesis. At the sub-cellular level, we uncovered that ACOs reside in the cytosol, where ethylene is likely synthesized, but surprisingly also in the nucleus. Using reverse genetics of single and higher order aco mutants we revealed a high degree of gene redundancy and minimal phenotypes. A lack of ethylene synthesis by knocking out all five ACOs did not impair normal vegetative and generative development but did influence processes associated with high rates of ethylene production such as petal abscission. This suggests that ethylene is not a prime regulator of development, but more a moderator. We also showed that the inability to synthesize ethylene impairs some abiotic (nutrient deficiency and metal toxicity) and biotic (Botrytis cinerea) stress responses, similar as plants insensitive towards ethylene, corroborating the role of ethylene in mediating stress responses. In conclusion, the ACO gene family enables plants to fine-tune their ethylene synthesis rates, but a lack their off is not crucial for normal development and stress survival.

plant biology↗

bioRxiv2023

Mechanosensing and Sphingolipid-Docking Mediate Lipopetide-Induced Immunity in Arabidopsis

Bacteria-derived lipopeptides are immunogenic triggers of host defenses in metazoans and plants. Root-associated rhizobacteria produce cyclic lipopeptides that activate systemically induced resistance (IR) against microbial infection in various plants. How these molecules are perceived by plant cells remains elusive. Here, we reveal that immunity activation in Arabidopsis thaliana by the lipopeptide elicitor surfactin is mediated by docking into specific sphingolipid-enriched domains and relies on host membrane deformation and subsequent activation of mechanosensitive ion channels. This mechanism leads to host defense potentiation and resistance to the necrotroph B. cinerea but is distinct from host pattern recognition receptor-mediated immune activation and reminiscent of damage-induced plant immunity.

plant biology↗