The novel gene Ny-1 on potato chromosome IX confers hypersensitive resistance to Potato virus Y and is an alternative to Ry genes in potato breeding for PVY resistance

Hypersensitive resistance (HR) is an efficient defense strategy in plants that restricts pathogen growth and can be activated during host as well as non-host interactions. HR involves programmed cell death and manifests itself in tissue collapse at the site of pathogen attack. A novel hypersensitivity gene, Ny-1, for resistance to Potato virus Y (PVY) was revealed in potato cultivar Rywal. This is the first gene that confers HR in potato plants both to common and necrotic strains of PVY. The locus Ny-1 mapped on the short arm of potato chromosome IX, where various resistance genes are clustered in Solanaceous genomes. Expression of HR was temperature-dependent in cv. Rywal. Strains PVYO and PVYN, including subgroups PVYNW and PVYNTN, were effectively localized when plants were grown at 20°C. At 28°C, plants were systemically infected but no symptoms were observed. In field trials, PVY was restricted to the inoculated leaves and PVY-free tubers were produced. Therefore, the gene Ny-1 can be useful for potato breeding as an alternative donor of PVY resistance, because it is efficacious in practice-like resistance conferred by Ry genes

Phylogeography and Molecular Evolution of Potato virus Y

Potato virus Y (PVY) is an important plant pathogen, whose host range includes economically important crops such as potato, tobacco, tomato, and pepper. PVY presents three main strains (PVYO, PVYN and PVYC) and several recombinant forms. PVY has a worldwide distribution, yet the mechanisms that promote and maintain its population structure and genetic diversity are still unclear. In this study, we used a pool of 77 complete PVY genomes from isolates collected worldwide. After removing the effect of recombination in our data set, we used Bayesian techniques to study the influence of geography and host species in both PVY population structure and dynamics. We have also performed selection and covariation analyses to identify evolutionarily relevant amino acid residues. Our results show that both geographic and host-driven adaptations explain PVY diversification. Furthermore, purifying selection is the main force driving PVY evolution, although some indications of positive selection accounted for the diversification of the different strains. Interestingly, the analysis of P3N-PIPO, a recently described gene in potyviruses, seems to show a variable length among the isolates analyzed, and this variability is explained, in part, by host-driven adaptation

Holocene demographic fluctuations, climate and erosion in the Mediterranean: A meta data-analysis

As part of the Changing the Face of the Mediterranean Project, we consider how human pressure and concomitant erosion has affected a range of Mediterranean landscapes between the Neolithic and, in some cases, the post-medieval period. Part of this assessment comprises an investigation of relationships among palaeodemographic data, evidence for vegetation change and some consideration of rapid climate change events. The erosion data include recent or hitherto unpublished work from the authors. Where possible, we consider summed probabilities of 14C dates as well as the first published synthesis of all known optically stimulated luminescence dated sequences. The results suggest that while there were some periods when erosion took place contemporaneously across a number of regions, possibly induced by climate changes, more often than not, we see a complex and heterogeneous interplay of demographic and environmental changes that result in a mixed pattern of erosional activity across the Mediterranean

Mise en evidence et caracterisation d'un nouveau pathotype du virus y de la pomme de terre

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Le phénomène de recombinaison observé chez le virus y de la pomme de terre (PYV) est-il impliqué dans l'apparition des nécroses sur tabac et sur tubercule de pomme de terre

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Variability of potato virus Y in potato crops in France

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Polymorphisme de la région 5'de l'ARN viral et critères de différenciation des souches du virus Y de la pomme de terre

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Hydro-geochemical analysis of the interplay between the groundwater, host rock and water curtain system for an underground oil storage facility

International audienceHydro-geochemical analysis was performed to investigate the interplay between the groundwater, host rock and water curtain system for the start-up of a pilot underground oil storage facility in China. 54 groundwater samples were collected and analyzed to obtain the characteristics of the hydro-geochemical environment evolution for the start-up period. The groundwater-rock mass interaction was studied with comparing the changes in the ion concentrations, pH values and total dissolved solid concentrations in the groundwater and a mineralogical analysis of the host rock. The groundwater-water curtain system interaction was identified using statistical analysis of the similarity in chemical contents in the groundwater samples. A mixing calculation was performed to evaluate the mixing ratios of the water curtain system, background water and oil/vapor in the seepage water into the storage caverns. It was concluded that calcium carbonate equilibrium is the predominant chemical reaction. The 54 groundwater samples could be classified into 5 clusters. Among the 5 clusters, there is one cluster showing that the tap water injected to the water curtain system is similar in chemical contents to those in the monitoring boreholes around the facility, which confirms the efficiency of the water curtain system for the start-up of the facility. It was found that the two dominant factors influencing the evolution of groundwater chemical content were host rock dissolution and groundwater seepage. Most of seepage water was originated from oil/vapor and water curtain system while the percentage from the background water was almost zero in the start-up period of the facility. © 2017 Elsevier Lt