Turnip yellow mosaic virus in Chinese cabbage in Spain: Commercial seed transmission and molecular characterization

[EN] Seed transmission of Turnip yellow mosaic virus (TYMV, genus Tymovirus) was evaluated in the whole seeds and seedlings that emerged from three commercial Chinese cabbage (Brassica pekinensis) seed batches. Seedlings in the cotyledon stage and adult plants were assayed for TYMV by DAS-ELISA and confirmed by RT-PCR. The proportion of whole seeds infected with TYMV was at least 0.15 %. The seeds of the three seed batches were grown in Petri dishes, and surveyed in the cotyledon stage in trays that contained a peat:sand mixture grown in greenhouses or growth chambers, which were analysed in the cotyledon and adult stages. The seed-to-seedling transmission rate ranged from 2.5 % to 2.9 % in two different seed batches (lot-08 and lot-09, respectively). Spanish isolates derived from turnip (Sp-03) and Chinese cabbage (Sp-09 and Sp-13), collected in 2003, 2009 and 2013 in two different Spanish regions, were molecularly characterised by analysing the partial nucleotide sequences of three TYMV genome regions: partial RNA-dependent RNA polymerase (RdRp), methyltransferase (MTR) and coat protein (CP) genes. Phylogenetic analyses showed that the CP gene represented two different groups: TYMV-1 and TYMV-2. The first was subdivided into three subclades: European, Australian and Japanese. Spanish isolate Sp-03 clustered together with European TYMV group, whereas Sp-09 and Sp-13 grouped with the Japanese TYMV group, and all differed from group TYMV-2. The sequences of the three different genomic regions examined clustered into the same groups. The results suggested that Spanish isolates grouped according to the original hosts from which they were isolated. 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Conjunctive Processing of Locomotor Signals by the Ventral Tegmental Area Neuronal Population

The ventral tegmental area (VTA) plays an essential role in reward and motivation. How the dopamine (DA) and non-DA neurons in the VTA engage in motivation-based locomotor behaviors is not well understood. We recorded activity of putative DA and non-DA neurons simultaneously in the VTA of awake mice engaged in motivated voluntary movements such as wheel running. Our results revealed that VTA non-DA neurons exhibited significant rhythmic activity that was correlated with the animal's running rhythms. Activity of putative DA neurons also correlated with the movement behavior, but to a lesser degree. More importantly, putative DA neurons exhibited significant burst activation at both onset and offset of voluntary movements. These findings suggest that VTA DA and non-DA neurons conjunctively process locomotor-related motivational signals that are associated with movement initiation, maintenance and termination

Host groups of Potato virus Y: vanishing barriers

Host groups of Potato virus Y: vanishing barrier

Diversity, Characterisation and Classification of PVY

International audienceSince the discovery of PVY in the 1930s, many strain groups and vari-ants have been described although consensus on an agreed international nomencla-ture is still a matter of debate. The challenge for plant pathologists studying PVY remains to establish the biological significance of the genomic diversity of PVY arising from the new, diverse PVY populations and how it impacts on crop produc-tion in practice. The distribution and range of PVY variants identified over the years highlight the ongoing threat that PVY poses to solanaceous crops worldwide. While genome sequencing provides accurate information on the genomic structure of an isolate and has become the method of choice as a first step to studying the phylog-eny of novel isolates and their affiliation to a genotypic group, it is not a sufficient criterion to assign a PVY isolate to a specific strain group, as groups are identified by a defined set of reactions or symptoms that develop following infection of a range of potato cultivars harbouring known resistance genes and on tobacco plants. The purpose of this chapter is to give an update on the current status of knowledge of PVY diversity identified in different geographical regions and insights into iden-tification and classification of PVY variants