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In this study differences in disease incidence between potato seed lots inoculated with soft rot Pectobacteriaceae were assessed in two years. Subsequently the microbial communities in tubers and soils from seed lots with a low and high disease incidence were determined by amplicon sequencing.

Cercospora leaf spot (CLS) caused by Cercospora traversiana is an important phyto-pathological problem of fenugreek (Trigonella foenum graecum), a multiuse legume crop. Knowledge about the inheritance of genes controlling CLS resistance is essential when selecting suitable breeding approaches while information about epidemiological factors affecting the disease can help develop new control strategies. Our greenhouse and field experiments showed CLS resistance in fenugreek (L3717 and PI138687) to be governed by a single dominant gene which is moderately heritable (46% narrow sense heritability). This indicates a relatively simple pathway for transfer of genes to adapted fenugreek cultivars. Rapid screening techniques (detached leaf assay and whole plant assay) were developed to identify the degree of resistance to C. traversiana in fenugreek genotypes. Several epidemiological factors such as temperature, physical injury (wounding), level of host resistance, plant age and inoculum concentration were found influencing CLS severity in controlled environment conditions.

Extracellular recognition of pathogens by plants constitutes an important early detection system in plant immunity. Microbe-derived molecules, also named patterns, can be recognized by pattern recognition receptors (PRRs) on the host cell membrane that trigger plant immune responses. Most knowledge on extracellular pathogen detection by plants comes from research on bacterial and fungal pathogens. For oomycetes, that comprise some of the most destructive plant pathogens, mechanisms of extracellular pattern recognition have only emerged recently. These include newly recognized patterns, e.g., cellulose-binding elicitor lectin, necrosis and ethylene-inducing peptide 1-like proteins (NLPs), and glycoside hydrolase 12, as well as their receptors, e.g., the putative elicitin PRR elicitin response and the NLP PRR receptor-like protein 23. Immunity can also be triggered by the release of endogenous host-derived patterns, as a result of oomycete enzymes or damage. In this review we will describe the types of patterns, both pathogen-derived exogenous and plant-derived endogenous ones, and what is known about their extracellular detection during (hemi-)biotrophic oomycete infection of plants.

Drosophila suzukii is threatening soft fruit production worldwide due to the females’ ability to pierce through the intact skin of ripe fruits and lay eggs inside. Larval consumption and the associated microbial infection cause rapid fruit degradation, thus drastic yield and economic loss. Cultivars that limit the proliferation of flies may be ideal to counter this pest; however, they have not yet been developed or identified. To search for potential breeding material, we investigated the rate of adult D. suzukii emergence from individual fruits (fly emergence) of 107 accessions of Fragaria species that had been exposed to egg-laying D. suzukii females. We found significant variation in fly emergence across strawberries, which correlated with accession and fruit diameter, and to a lesser extent with the strawberry species background. We identified accessions with significantly reduced fly emergence, not explained by their fruit diameter. These accessions constitute valuable breeding material for strawberry cultivars that limit D. suzukii spread., Peer Reviewed

Allelic diversity is a fundamental requirement for successful plant breeding programs. When gene pool is limited, several mechanisms are available for variability enrichment, for example, obtaining somaclonal variants through in vitro techniques. Somaclonal variation is a natural phenomenon that occurs in the procedures of plant tissue culture, through is possible to recover mutants with or without adaptive advantages. When this phenomenon is used to generate mutants with specific traits, through the use of an agent of artificial selection, the process is called in vitro selection. When looking for generating plant material that is resistant/tolerant to diseases, the agent of choice may be the causative organism, its parts, or its metabolic products, including toxins. Considerations of cost, simplicity and efficiency, make this technique particularly suitable for developing countries. In this paper, we review the scientific basis underpinning this method., Resumen.- La diversidad alélica es un requisito fundamental para el éxito de los programas de fitomejoramiento. En casos en los que la reserva de genes es escasa existen varios mecanismos para aumentarla artificialmente, incluyendo la obtención de variantes somaclonales a través de técnicas de cultivo de tejidos vegetales in vitro. La variación somaclonal es un fenómeno natural que ocurre en los procedimientos de cultivo de tejidos, a través del cual pueden recuperarse mutantes con o sin ventajas adaptativas. Cuando este fenómeno se utiliza para generar mutantes con características prediseñadas, a través del uso de un agente de selección artificial, el proceso se denomina selección in vitro. Si lo que se busca es producir material vegetal con resistencia y/o tolerancia a enfermedades, el agente de selección puede ser el microorganismo etiológico, sus partes, o sus productos metabólicos, incluidas sus toxinas. Consideraciones de costo, sencillez y eficacia, hacen que esta técnica sea particularmente apta para los países en vía de desarrollo. En este documento se revisan los fundamentos científicos que la sustentan.

Allelic diversity is a fundamental requirement for successful plant breeding programs. When gene pool is limited, several mechanisms are available for variability enrichment, for example, obtaining somaclonal variants through in vitro techniques. Somaclonal variation is a natural phenomenon that occurs in the procedures of plant tissue culture, through is possible to recover mutants with or without adaptive advantages. When this phenomenon is used to generate mutants with specific traits, through the use of an agent of artificial selection, the process is called in vitro selection. When looking for generating plant material that is resistant/tolerant to diseases, the agent of choice may be the causative organism, its parts, or its metabolic products, including toxins. Considerations of cost, simplicity and efficiency, make this technique particularly suitable for developing countries. In this paper, we review the scientific basis underpinning this method., Resumen.- La diversidad alélica es un requisito fundamental para el éxito de los programas de fitomejoramiento. En casos en los que la reserva de genes es escasa existen varios mecanismos para aumentarla artificialmente, incluyendo la obtención de variantes somaclonales a través de técnicas de cultivo de tejidos vegetales in vitro. La variación somaclonal es un fenómeno natural que ocurre en los procedimientos de cultivo de tejidos, a través del cual pueden recuperarse mutantes con o sin ventajas adaptativas. Cuando este fenómeno se utiliza para generar mutantes con características prediseñadas, a través del uso de un agente de selección artificial, el proceso se denomina selección in vitro. Si lo que se busca es producir material vegetal con resistencia y/o tolerancia a enfermedades, el agente de selección puede ser el microorganismo etiológico, sus partes, o sus productos metabólicos, incluidas sus toxinas. Consideraciones de costo, sencillez y eficacia, hacen que esta técnica sea particularmente apta para los países en vía de desarrollo. En este documento se revisan los fundamentos científicos que la sustentan.

Soybean mosaic virus (SMV), has been the cause of numerous and often devastating disease epidemics, causing reduction in both the quality and quantity of soybeans worldwide. Two important genes for resistance to SMV are Rsv1 and Rsv4. Alleles at the Rsv1 locus have been shown to control resistance to all but the most virulent strain of SMV. This locus has been mapped previously to the soybean F linkage group. Rsv4 is an SMV resistance locus independent of Rsv1 and confers resistance to all strains of SMV. This locus has not been mapped previously. The purpose of this study is to investigate the two genomic regions that contain these vitally important resistance genes. A population of 281 F2 individuals that had previously been genotyped for reaction to SMV was evaluated in a mapping study which combined bulk segregant analysis with Amplified Fragment Length Polymorphism (AFLP). A Rsv4-linked marker, R4-1, was identified that mapped to soybean linkage group D1b using a reference mapping population. More than 40 markers were mapped in the Rsv4 segregating population including eleven markers surrounding Rsv4. This will provide the necessary framework for the fine mapping of this important genetic locus. Previous work has located Rsv1 to a genomic region containing several important resistance genes including Rps3, Rpg1, and Rpv. An RFLP probe, NBS5, whose sequence closely resembles that of several cloned plant disease resistance genes has been mapped to this chromosomal region. The efficacy of using this sequence to identify potential disease resistance genes was assessed by screening a cDNA library to uncover a candidate disease resistance gene which corresponds to this NBS5 sequence. Two related sequence classes were identified that correspond to NBS5. Interestingly, one class corresponds to a full length gene closely resembling other previously cloned disease resistance genes offering evidence that this NBS5-derived clone is a candidate disease resistance gene. A ne

Breeding and seed orchard plan for the development of blister rust resistant white pine for the northern Rockies

Stress physiology, patterns in defensive chemistry, and spruce budworm success