Biology subjects

Canal, M.

Publications and source records attributed to Canal, M..

3 recordsLinked to original sources

bioRxiv2026

A fatal plant toxicosis described more than a century ago is caused by a bacterial endophyte

Gousiekte ( quick disease) is a fatal plant toxicosis affecting livestock in South Africa. Gousiekte is characterized by the sudden death of animals following the ingestion of leaves of several species of Rubiaceae, most notably Vangueria pygmaea, Pavetta harborii, P. schumanniana and Fadogia homblei. The toxin causing gousiekte is pavettamine, a hydroxylated polyamine pavettamine for which no biosynthetic pathway is known. Interestingly, all plants known to contain pavettamine also feature obligate endophytes of the Burkholderiaceae family, in particular belonging to the Caballeronia and Paraburkholderia genera. We identified a cluster of three genes conserved in all Burkholderia s.l. endophytic symbionts of plants containing pavettamine. Constitutive expression the pavABC gene cluster in a strain of Paraburkholderia caledonica isolated from leaves of Fadogia homblei resulted in detectable levels of pavettamine in cultures, and targeted gene deletions showed the involvement of all three genes in its biosynthesis. Genomes of important animal and human pathogens of the Burkholderia pseudomallei complex encode functional homologs of the pavABC genes, indicating a potentially unrecognized role of pavettamine in disease or complications from infections. Significance statementGousiekte is a fatal disease of livestock caused by plants containing the toxin pavettamine, yet the origin of this compound has remained a mystery. We demonstrate that pavettamine is synthesized not by the plants themselves, but by their obligate bacterial endophytes via a conserved three-gene cluster, pavABC. Crucially, these genes were likely acquired via horizontal gene transfer from an ancestor of the Burkholderia pseudomallei complex, a group of significant human and animal pathogens. This discovery identifies the genetic basis of a potent toxin and suggests a previously unrecognized role for pavettamine in human infectious diseases. This work emphasizes the preeminent role of horizontal gene transfer and secondary metabolism for host-microbe interactions.

microbiology↗

bioRxiv2025

Non-invasive eDNA reveals the ecological and genetic status of the Western Capercaillie (Tetrao urogallus aquitanicus) in the Eastern Pyrenees

The Anthropocene era is expected to bring about significant biodiversity and habitat loss for many species. These geographical changes, whether driven by climatic or anthropogenic factors, are likely to lead to considerable alterations in population size, structure, and genetic diversity. Monitoring natural populations is therefore essential to assess these impacts and enable informed conservation strategies for threatened species. The Western Capercaillie (Tetrao urogallus, L. 1758) has a widespread distribution in Boreal forests but fragmented in mountainous regions of the Palearctic, and is locally threatened by climate change, habitat destruction, and human disturbance. Our study focused on the eastern population of the subspecies T. u. aquitanicus, which is endemic to the Pyrenees mountains. The monitoring of this population has relied on direct methods and no genetic information had been generated so far. Here, we conducted a molecular study based on 229 non-invasive samples (faeces) to assess the ecological and genetic status of local population in the Catalan Nature Reserves of the Pyrenees-Orientales (Occitanie region, France). At the individual level, we assessed multi-locus genotypes, sexing, levels of inbreeding, stress level (Fecal Corticosterone Metabolites; FCMs) and diet. At the population level, we assessed sex ratio, genetic diversity and structure. We identified 62 individuals with a balanced sex ratio and estimated a census size of 79 individuals [95%CI = 68-92] in the study area. Genetic diversity was low and suggested significant inbreeding levels. FCM levels were lower in birds of areas considered as disturbed by humans and metabarcoding approach indicated a geographical structuring of diet composition at the reserve scale, with individuals exhibiting feeding behavior upon only one or few plant species. Our estimate of population census size was higher with figures assessed from lek counts, and the genetic approach provided additional insights on this population, establishing a baseline that will support conservation management plans.

ecology↗

bioRxiv2020

RTP801 Is A Key Modulator For Motor Learning

RTP801/REDD1 is a stress-regulated protein whose upregulation is necessary and sufficient to trigger neuronal death in in vitro and in vivo models of Parkinsons and Huntingtons diseases and is up regulated in compromised neurons in human postmortem brains of both neurodegenerative disorders. Indeed, in both Parkinsons and Huntingtons disease mouse models, RTP801 knockdown alleviates motor-learning deficits. Here, we investigated the physiological role of RTP801 in neuronal plasticity. RTP801 is found in rat, mouse and human synapses. The absence of RTP801 enhanced excitatory synaptic transmission in both neuronal cultures and brain slices from RTP801 knock-out (KO) mice. Indeed, RTP801 KO mice showed improved motor learning, which correlated with lower spine density but increased basal filopodia and mushroom spines in the motor cortex layer V. This paralleled with higher levels of synaptosomal GluA1 and TrkB receptors in homogenates derived from KO mice motor cortex, proteins that are associated with synaptic strengthening. Altogether, these results indicate that RTP801 has an important role modulating neuronal plasticity in motor learning.

neuroscience↗