Alicia Camuel Research Portfolio

Research interests

One of the questions that has always fascinated me is how plants, as immobile organisms, have managed to adapt and cope with everything around them without being able to move as other living organisms do. Faced with this apparent constraint, plants have evolved strategies to interact with their environment and survive, allowing them to colonize the land long before animals.

A plant is in constant interaction with its surroundings, leading to biotic stresses (pathogen attack, weeds, animals, etc.) and abiotic stresses (drought, nutrient deficiency, temperature, etc.). To cope with these challenges, plants have developed numerous strategies, ranging from the molecular scale to the rhizosphere and phyllosphere. I therefore devote my research time to better understanding the interactions between plants and their environment, and how these interactions have shaped and continue to shape plant organisms.

Since joining SLCU in 2025, my work has focused on the study of effectors, which are microbial proteins that are directly secreted into plants by microorganisms and that modulate plant development.

Abaxial surface of 10-day-old A. thaliana leaves expressing or not expressing a Phytophthora palmivora effector. A normal development is observed in the absence of the effector (left), while stomatal clustering is visible in its presence (right). The leaves were observed using a Leica confocal microscope after staining with 0.1 mg/ml PI.

Research background

Over the past five years, I have developed expertise in plant biology and microbiology, with a particular focus on plant-microbe interactions and effector biology.

During my PhD, I investigated a Type III Secretion System (T3SS)-dependent symbiotic strategy in tropical legumes. I identified a novel family of effectors, ET-Nods, capable of triggering spontaneous nodulation, and demonstrated their widespread distribution across bacterial strains. This work combined comparative genomics, targeted mutagenesis, and ectopic expression, hence highlighting how microbial effectors are able to reprogram plant development.

As a postdoctoral researcher, I significantly advanced our understanding of the legume-rhizobium nitrogen-fixing symbioses by continuing my doctoral work, with a particular focus on the plant partner.  By inoculating various Bradyrhizobium strains harbouring different combinations of ET-Nods, I investigated whether these plant determinants are recruited and where ET-Nods act within the signalling pathway. This work revealed that some plant signalling symbiotic determinants (NIN and NSP2), are common between NF-dependent and NF-independent symbioses. However, and contrary to expectations, certain genes previously thought essential for all legume-rhizobium symbioses (POLLUX, CCaMK, CYCLOPS), are actually dispensable during T3SS-triggered nodulation. In parallel, the establishment of a genetic pipeline in the tropical legume Aeschynomene evenia, including inducible expression systems, stable transformation and CRISPR-Cas9 editing, will facilitate precise gene function analysis within the context of T3SS-dependent symbiosis.

These findings shed light on the genetic diversity of nitrogen-fixing symbioses, demonstrating that ET-Nods can activate alternative nodulation pathways thereby expanding our understanding of symbiotic mechanisms. This research offers insights into nitrogen-fixing symbioses evolution while opening new avenues to enhance legume crop yields through optimised symbiotic interactions.

A. evenia roots transformed either with the empty vector containing the DsRed marker (A–C) or with p35S-sup3 (D–F) at 7 weeks after transformation (no bacterial inoculation). Roots were observed by a fluorescence stereomicroscope equipped with a DsRed filter. Scale bars: A and D, 2 mm; B, C, E and F, 500 µm. Micro-sections of pseudo-nodules observed using light microscopy showing the peripheral vascularization (G) and using a confocal microscope (H) after staining with SYTO 9, propidium iodide and calcofluor showing that the induced pseudo-nodules do not contain bacteria. Scale bars G and H, 200 µm.