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Each season, crops face simultaneous or successive multiple infections. Yet cultivar resistance is often bred against one pest at a time, and screened under single infections. This raises the question of resistance expression bred under mono‐infections when exposed to multiple infections. We tackled this question by measuring the level of quantitative resistance of potato cultivars to either Globodera pallida or Phytophthora infestans under single or multiple infections, using potato virus Y (PVY) or Rhizoctonia solani as the co‐infector. Overall, co‐infection resulted in less multiplication of the target pathogen compared to single infection, although this reduction did not always reach statistical significance. A preliminary assessment of defence gene expression in plants infected with P. infestans alone or together with PVY or R. solani suggested that P. infestans repressed defence genes previously triggered by PVY, but boosted the expression of these genes when primed by R. solani. Together, these data support the view that resistance expression is impacted by co‐infection, and that it should be screened under multiple infection situations to be best assessed and exploited as a component of Integrated Pest Management strategies. [ABSTRACT FROM AUTHOR]

Accurate management practices in crop health and food safety are critical, especially regarding the detection of plant pathogens in the early stages of a disease. To date, specific, fast and sensitive technologies for point‐of‐care diagnosis and simple or grower‐friendly devices are very valuable, as no specialized staff are required for diagnosing a disease in the field. This is especially the case today, when factors such as climate change may cause the appearance of pathogens in areas where years ago they were unexpected. The aim of this research is to review some of the promising techniques that can be applied to in‐field molecular detection of plant pathogens and how these techniques can change the way farmers and pathologists are diagnosing plant diseases. Some of them, like loop‐mediated isothermal amplification and recombinase polymerase amplification, are already being successfully used for routine diagnosis. However, most technologies still need validation in the plant pathology field, where they have a promising future for in‐field diagnosis when combined with simple DNA extraction methods, reagent stabilization techniques and their integration into portable devices. [ABSTRACT FROM AUTHOR]

Virus‐induced systemic necrosis accounts for great yield losses in potato (Solanum tuberosum) cultivars susceptible to the necrotic strain of potato virus Y (PVYNTN). To extend understanding of systemic necrosis, the tissue of healthy and PVYNTN‐infected potato tubers (necrotic and non‐necrotic) during storage was profiled for host gene expression using microarrays while virus concentration was determined using RT‐qPCR. Comparison of non‐necrotic tissue types revealed minor transcriptional differences, while tuber necrosis was characterized by high virus concentration and pronounced expression of defence response‐associated genes. Creation of programmed cell death‐associated gene ontology enabled assessment of expression and regulation of relevant differentially expressed genes implicated in the execution of plant programmed cell death. Vacuolar cell death and unfolded protein response to viral infection were implicated in the necrotic tuber tissue by transcriptional induction of genes possessing caspase‐like activity and genes coding for endoplasmic reticulum chaperones and folding proteins. A meta‐analysis, including all relevant publicly available gene expression datasets differing in genotype, pathogen interaction type and potato organ, revealed common defence responses associated with cell wall fortification, oxidative and biotic stress. The response in necrotic tissues of susceptible tubers resembled the hypersensitive response of resistant primary infected plants, but with hormonal signalling as an important differentiating factor. This study will be useful for in‐depth analysis of programmed cell death regulation in plants by providing gene ontology. It specifically addresses the issue of systemic necrosis formation in PVYNTN‐infected potato tubers during storage. [ABSTRACT FROM AUTHOR]