Biology subjects

Morel, J.-B.

Publications and source records attributed to Morel, J.-B..

4 recordsLinked to original sources

bioRxiv2026

Root phenolics as potential drivers of preformed defenses and reduced disease susceptibility in a paradigm bread wheat mixture

Plant-plant interactions modulate foliar disease susceptibility in intraspecific mixtures. However, the molecular events including signals and responses underlying the reduction in disease susceptibility remain largely unexplored. Here, we developed an experimental system that can abolish root-mediated interactions between plants in a model of bread wheat varietal mixture. We then performed transcriptomic and metabolomic analyses to uncover the molecular responses linked to decreased susceptibility to Septoria tritici blotch in plant-plant interactions. Our analysis revealed that disrupting root chemical interactions impaired the reduction in susceptibility to Septoria and identified phenolic compounds as potential key mediators. The plant-plant interactions under study triggered significant molecular changes in specialized metabolism, biotic interactions, transporters, and responses to resources. Disrupting root interactions canceled both the macroscopic and molecular responses, thus providing a strong link between them. These insights provide a deeper understanding of the molecular basis of plant-plant interactions and the processes involved in reducing disease susceptibility in intraspecific mixtures. Significance statementNeighboring plants mediate resistance to leaf fungal pathogens by releasing root-derived molecules. These interactions trigger multi-omic reprogramming of defenses in both leaves and roots. Enhanced resistance in varietal mixtures is associated with the early activation of defense pathways. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=186 SRC="FIGDIR/small/699261v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@16f02a9org.highwire.dtl.DTLVardef@117b872org.highwire.dtl.DTLVardef@4e5243org.highwire.dtl.DTLVardef@1fac682_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstractC_FLOATNO C_FIG

plant biology↗

bioRxiv2024

Plant-plant interactions in wheat mixtures modulate mean and variance of susceptibility to Septoria tritici blotch

Varietal mixtures are a promising agro-ecological approach to stabilizing yields by reducing diseases. The effects of mixtures stem from modifications of epidemiological processes and plant-plant interactions, which could explain some of the paradoxical observations made in the field. However, the role of plant-plant interactions in modifying bread wheat and durum wheat susceptibility to septoria tritici blotch remains to be elucidated. Our study aimed to determine the effect of such plant-plant interactions, by producing full matrices of binary mixtures in the absence of epidemics, on septoria symptoms--specifically necroses (lesions) and pycnidia (spore-containing structures). We employed statistical modeling to compare the mean and variance of focal plants phenotype in all mixtures versus pure conditions and in each mixture versus pure condition. Our findings demonstrate significant effects of plant-plant interactions on wheat susceptibility to septoria. Notably, these interactions had specific rather than general effects, with some but not all genotypic combinations significantly influencing focal susceptibility to septoria. Furthermore, mixtures resulted in reduced necrosis with lower variance, but increased pycnidia formation. These results reinforce the need to consider specific plant-plant interactions for their contribution to trait means and variances. Better considering these interactions could improve crop management strategies that enhance disease control. HighlightWheat varietal mixtures modulate the mean and variance of septoria disease symptoms through specific plant-plant interactions. Mixtures reduce lesions and their variance but increase the formation of spore-containing bodies.

plant biology↗

bioRxiv2024

Cytokinin-induced immunity enhances rice blast resistance

Plant cytokinins (CKs) affect the outcome of plant-pathogen interactions. However, despite many examples their role remains ambiguous. In rice, CKs act synergistically with salicylic acid (SA) to induce defense genes in vitro but no effect on resistance against the blast fungus, Magnaporthe oryzae, was further observed in planta. Here, we demonstrate that exogenous CKs treatment triggers rice blast resistance in a molecule-, dose- and time-dependent manner by affecting defense- and CK-responsive genes. Similar enhanced resistance and gene expression patterns were confirmed in rice insertion mutant lines impaired for a gene that encodes a putative CK inactivation enzyme, supporting that endogenous CKs affect rice immunity. Together, our work brings insights on the CK-induced resistance of rice to M. oryzae.

plant biology↗

bioRxiv2021

COEVOLUTION WITH SPATIALLY STRUCTURED RICE LANDRACES MAINTAINS MULTIPLE GENERALIST LINEAGES IN THE RICE BLAST PATHOGEN

Traditional agrosystems, where humans, crops and microbes have coevolved over long periods, can serve as models to understand the eco-evolutionary determinants of disease dynamics and help the engineering of durably resistant agrosystems. Here, we investigated the genetic and phenotypic relationship between rice (Oryza sativa) landraces and their rice blast pathogen (Magnaporthe oryzae) in the traditional Yuanyang terraces of flooded rice paddies in China, where rice landraces have been grown and bred over centuries without significant disease outbreaks. Analyses of genetic subdivision revealed that indica rice plants clustered according to landrace names. Three new diverse lineages of rice blast specific to the Yuanyang terraces coexisted with lineages previously detected at the worldwide scale. Population subdivision in the pathogen population did not mirror pattern of population subdivision in the host. Measuring the pathogenicity of rice blast isolates on landraces revealed generalist life histories. Our results suggest that the implementation of disease control strategies based on the emergence or maintenance of a generalist lifestyle in pathogens may sustainably reduce the burden of disease in crops.

evolutionary biology↗