Pectin methyl esterases and rhamnogalacturonan hydrolases: weapons for successful Monilinia laxa infection in stone fruit?

The secretion of cell wall‐degrading enzymes is one of the mechanisms used by necrotrophic fungi to colonize host tissues. However, information about virulence factors of Monilinia spp., the causal agents of brown rot in stone fruit, is scarce. Plant cell walls have three main components that are broken down by fungal enzymes: cellulose, hemicellulose and pectin. In order to identify Monilinia laxa candidate proteins involved in pectin hydrolysis, two in vitro approaches were conducted: (i) phenotypic and ecophysiological characterization of growth of the pathogen at different pHs, in glucose‐ and pectin‐containing solid media for 7 days' incubation; and (ii) expression analysis of genes encoding M. laxa pectin methyl esterases (MlPMEs) and rhamnogalacturonan hydrolases (MlRG‐HYDs) after incubation for 0.5, 2, 6, 24 and 48 h in glucose‐ and pectin‐containing liquid media. Phenotypic tests showed the role of carbon source on M. laxa growth rate and aggressiveness, and indicated that pectinases were greatly affected by pH. Gene expression analyses uncovered differences among members of each family of pectinases and between the two families, defining sets of genes expressed at earlier (0.5–6 h) and later (48 h) phases. Notably, the up‐ or down‐regulation of these target genes was carbon source‐dependent. Finally, an in vivo study confirmed the synergistic and complementary role that these genes play in the M. laxa–stone fruit pathosystem. Based on these results, it is hypothesized that MlPME2, MlRG‐HYD1 and MlRG‐HYD2 may be potential virulence factors of M. laxa in the process from infection to colonization.info:eu-repo/semantics/acceptedVersio

Genomic-based breeding for climate-smart peach varieties

Improving the performance of peach varieties in the context of climate change requires multiple approaches. Not only will climate change alter plant phenology, but it will also drive negative effects of several biotic and abiotic stressors. The challenge is to improve adaptation of varieties to a changing environment, while maintaining organoleptic qualities of the fruit. This chapter focuses on the progress in genomics-assisted breeding in peach to break barriers in conventional breeding. Breeding climate-smart (CS) peach trees requires the identification of CS traits used in the adaptation to high levels of temperature, CO2, water deprivation and biotic stress. Relevant CS traits, such as those that control flowering time (chilling and heat requirements), biotic and abiotic stress tolerance (pests and diseases; water-nutrient efficiency), require prioritization. Here, we review classical mapping and breeding of peach varieties, the progress and limitations of the used of marker-assisted selection and breeding (MAS and MAB, respectively) in expression of traits, such as fruit quality and stress tolerance, and describe the rationale for the use of molecular breeding.EEA San PedroFil: Gogorcena Aoiz, Yolanda. Consejo Superior de Investigaciones Científicas (CSIC). Estación Experimental Aula Dei; EspañaFil: Sánchez, Gerardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Moreno-Vázquez Santiago. Universidad Politécnica de Madrid. Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas; EspañaFil: Pérez, Salvador. Centro de Recursos Geneticos y Mejoramiento de Prunus; MéxicoFil: Ksouri, Najla. Consejo Superior de Investigaciones Científicas (CSIC). Estación Experimental Aula Dei; Españ