A novel pathosystem between Aeschynomene evenia and Aphanomyces euteiches reveals new immune components in quantitative legume root-rot resistance.
Authors: Baker, M., Martinez, Y., Keller, J., Sarrette, B., Pervent, M., Libourel, C., Le Ru, A., Bonhomme, M., Gough, C., Castel, B., ARRIGHI, J.-F., Jacquet, C.
The study establishes Aeschynomene evenia as a new model for dissecting legume immunity against the soilborne pathogen Aphanomyces euteiches and its relationship with Nod factor-independent symbiosis. Quantitative resistance was assessed through inoculation assays, phenotypic and cytological analyses, and RNA‑seq identified thousands of differentially expressed genes, highlighting immune signaling and specialized metabolism, with mutant analysis confirming dual‑function kinases that modulate resistance. Comparative transcriptomics with Medicago truncatula revealed conserved and unique immune responses, positioning the A. evenia–A. euteiches system as a valuable platform for exploring quantitative resistance and symbiosis integration.
The authors compiled and standardized published data on Rubisco dark inhibition for 157 flowering plant species, categorizing them into four inhibition levels and analyzing phylogenetic trends. Their meta‑analysis reveals a complex, uneven distribution of inhibition across taxa, suggesting underlying chloroplast microenvironment drivers and providing a new resource for future photosynthesis improvement efforts.
The study investigates late‑stage effector genes of the fungus Leptosphaeria maculans that infect Brassica napus stems, assessing whether these effectors are more conserved than early‑stage ones and thus may confer more durable resistance. Six candidate late effectors were selected and screened across an expanded set of semi‑winter B. napus genotypes, revealing new resistance sources predominantly within this genetic pool, supporting the hypothesis of greater stability of late effectors.
The study employed deep learning–based image analysis to monitor 6,889 individual lesions caused by Zymoseptoria tritici on 14 wheat cultivars in field conditions, generating over 27,000 precise measurements of lesion growth. Lesion expansion was found to be a significant, moderately heritable component of quantitative resistance (QR) in most cultivars, and its variation correlated strongly with overall QR after exclusion of an outlier. These findings highlight lesion growth as a valuable target for breeding durable QR in wheat.