Biology subjects

Gaston, M.

Publications and source records attributed to Gaston, M..

3 recordsLinked to original sources

bioRxiv2024

A new group of LysM-RLKs involved in symbiotic signal perception and arbuscular mycorrhiza establishment

Lipo-chitooligosaccharides (LCO) and short-chain chitooligosaccharides (CO) are produced by arbuscular mycorrhizal fungi (AMF) and activate the plant symbiosis signalling pathway, which is essential for mycorrhiza formation. High affinity LCO receptors belonging to the LysM receptor-like kinase (LysM-RLK) phylogenetic group LYR-IA play a role in AM establishment, but no plant high affinity short-chain CO receptors have yet been identified. Here we studied members of the uncharacterized LYR-IB group, and found that they show high affinity for LCO, short- and long-chain CO, and play a complementary role with the LYR-IA LCO receptors for AM establishment. While LYR-IB knock out mutants had a reduced AMF colonization in several species, constitutive/ectopic expression in wheat increased AMF colonization. LYR-IB function is conserved in all tested angiosperms, but in most japonica rice a deletion creates a frameshift in the gene, explaining differences in AM phenotypes between rice and other monocot single LYR-IA mutants. In conclusion, we identified a class of LysM-RLK receptors in angiosperms with new biochemical properties and a role in both LCO and CO perception for AM establishment.

plant biology↗

bioRxiv2020

Rhizobium leguminosarum symbiovar viciae strains are natural wheat endophytes and can stimulate root development and colonization by arbuscular mycorrhizal fungi

O_LIAlthough rhizobia establishing a nitrogen-fixing symbiosis with legumes are also known to promote growth in non-legumes, studies on rhizobia association with wheat roots are scarce. C_LIO_LIWe searched for Rhizobium leguminosarum symbiovar viciae (Rlv) strains naturally competent for wheat roots colonization. We isolated 20 strains and tested the ability of a subset for wheat roots colonization when co-inoculated with other Rlv. We also measured the effect of these strains on wheat root architecture and Arbuscular Mycorrhizal Fungal (AMF) colonization. C_LIO_LIWe found a low diversity of Rlv in wheat roots compared to that observed in the Rlv species complex. Only a few strains, including those isolated from wheat roots, and one strain isolated from pea nodules, were efficient to colonize wheat roots in co-inoculation conditions. These strains had a high ability for endophytic colonization of wheat root and were able to stimulate root development and AMF colonization in single strain inoculation conditions. C_LIO_LIThese results suggest that wheat is an alternative host for some Rlv; nevertheless, there is a strong competition between Rlv strains for wheat root colonization. Furthermore, our study suggests that the level of endophytic colonization is critical for Rlv ability to promote wheat growth. C_LI

microbiology↗

bioRxiv2019

Experimental system and image analysis software for high throughput phenotyping of mycorrhizal growth response in Brachypodium distachyon

O_LIPlant growth response to Arbuscular Mycorrhizal (AM) fungi is variable and depends on genetic and environment factors that still remain largely unknown. Identification of these factors can be envisaged using high-throughput and accurate plant phenotyping.\nC_LIO_LIWe setup experimental conditions based on a two-compartment system allowing to measure Brachypodium distachyon mycorhizal growth response (MGR) in an automated phenotyping greenhouse. We developed a new image analysis software \"IPSO Phen\" to estimate of B. distachyon aboveground biomass.\nC_LIO_LIWe found a positive MGR in the B. distachyon Bd3-1 genotype inoculated with the AM fungi Rhizophagus irregularis only if nitrogen and phosphorus were added together in the compartment restricted to AM fungi. Using this condition, we found genetic diversity in B. distachyon for MGR ranging from positive to negative MGR depending on the plant genotype tested.\nC_LIO_LIOur result on the interaction between nitrogen and phosphorus for MGR in B. distachyon opens new perspectives about AM functioning. In addition, our open-source software allowing to test and run image analysis parameters on large amount of images generated by automated plant phenotyping facilities, will help to screen large panels of genotypes and environmental conditions to identify the factors controlling the MGR.\nC_LI

plant biology↗