RESUMEN
Clubroot caused by the protist Plasmodiophora brassicae is a major disease affecting cultivated Brassicaceae. Using a combination of quantitative trait locus (QTL) fine mapping, CRISPR-Cas9 validation, and extensive analyses of DNA sequence and methylation patterns, we revealed that the two adjacent neighboring NLR (nucleotide-binding and leucine-rich repeat) genes AT5G47260 and AT5G47280 cooperate in controlling broad-spectrum quantitative partial resistance to the root pathogen P. brassicae in Arabidopsis and that they are epigenetically regulated. The variation in DNA methylation is not associated with any nucleotide variation or any transposable element presence/absence variants and is stably inherited. Variations in DNA methylation at the Pb-At5.2 QTL are widespread across Arabidopsis accessions and correlate negatively with variations in expression of the two genes. Our study demonstrates that natural, stable, and transgenerationally inherited epigenetic variations can play an important role in shaping resistance to plant pathogens by modulating the expression of immune receptors.
Asunto(s)
Arabidopsis , Resistencia a la Enfermedad , Enfermedades de las Plantas , Arabidopsis/genética , Arabidopsis/inmunología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/parasitología , Resistencia a la Enfermedad/genética , Proteínas NLR/genética , Proteínas NLR/metabolismo , Metilación de ADN , Plasmodiophorida/fisiología , Sitios de Carácter Cuantitativo/genética , Proteínas de Arabidopsis/genética , Epigénesis Genética , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , AlelosRESUMEN
Consumers began to complain about the taste of tomato varieties in the late 1990's. Although tomato taste is influenced by environmental and post-harvest conditions, varieties show a large diversity for fruit quality traits. We herein review our past and present research work intended to improve tomato fruit quality. First, results from sensory analysis allowed identifying important traits for consumer preferences. Then, we dissected the genetic control of flavor related traits by mapping several QTL in the last 20 years, and identified the genes corresponding to a few major QTL. Since the availability of the tomato genome sequence, genome-wide association studies were performed on several panels of tomato accessions. We discovered a large number of associations for fruit composition and identified relevant allele combinations for breeding. We then performed a meta-analysis combining the results of several studies. We also checked the inheritance of quality traits at the hybrid level and assessed how genomic prediction could help selecting better tomato varieties.
Les consommateurs ont commencé à se plaindre du goût des variétés de tomates à la fin des années 1990. Bien que le goût de la tomate soit influencé par les conditions de culture et de post-récolte, les variétés présentent une grande diversité pour les caractéristiques de qualité des fruits. Nous passons ici en revue nos travaux de recherche passés et présents destinés à comprendre la diversité génétique et améliorer la qualité des fruits de tomate. Les résultats d'analyses sensorielles ont tout d'abord permis d'identifier les traits importants pour les préférences des consommateurs. Ensuite, nous avons disséqué le contrôle génétique des caractères liés à ces traits, cartographié de nombreux QTL depuis 20 ans et identifié les gènes correspondant à quelques QTL majeurs. Depuis la disponibilité de la séquence du génome de la tomate, des études d'association à l'échelle du génome ont été réalisées sur plusieurs panels d'accessions de tomate. Nous avons découvert un grand nombre d'associations pour la composition des fruits, et identifié les combinaisons d'allèles pertinentes pour la sélection. Nous avons ensuite réalisé une méta-analyse combinant les résultats de plusieurs études. Nous avons également vérifié l'hérédité des caractères de qualité au niveau hybride, et évalué comment la prédiction génomique pourrait aider à sélectionner de meilleures variétés de tomates.
Asunto(s)
Solanum lycopersicum , Solanum lycopersicum/genética , Estudio de Asociación del Genoma Completo , Sitios de Carácter Cuantitativo/genética , Frutas/genética , FitomejoramientoRESUMEN
Diversifying disease control methods is a key strategy to sustainably reduce pesticides. Plant genetic resistance has long been used to create resistant varieties. Plant resistance inducers (PRI) are also considered to promote crop health, but their effectiveness is partial and can vary according to the environment and the plant genotype. We investigated the putative interaction between intrinsic (genetic) and PRI-induced resistance in apple when affected by scab and fire blight diseases. A large F1 mapping population was challenged by each disease after a pre-treatment with acibenzolar-S-methyl (ASM) and compared with the water control. Apple scab and fire blight resistance quantitative trait loci (QTLs) were detected in both conditions and compared. ASM exhibited a strong effectiveness in reducing both diseases. When combined, QTL-controlled and ASM-induced resistance acted complementarily to reduce the symptoms from 85 to 100%, depending on the disease. In our conditions, resistance QTLs were only slightly or rarely affected by ASM treatment, despite their probable implication in various stages of the resistance buildup. Implications of these results are discussed considering already known results, the underlying mechanisms, cross protection of both types of resistance against pathogen adaptation, and practical application in orchard conditions.
