Retrotransposon-Based Genetic Diversity Assessment in Wild Emmer Wheat (Triticum turgidum ssp. dicoccoides)

Wild emmer wheat (Triticum turgidum ssp. dicoccoides) is the wild ancestor of all cultivated tetraploid and hexaploid wheats and harbors a large amount of genetic diversity. This diversity is expected to display eco-geographical patterns of variation, conflating gene flow, and local adaptation. As self-replicating entities comprising the bulk of genomic DNA in wheat, retrotransposons are expected to create predominantly neutral variation via their propagation. Here, we have examined the genetic diversity of 1 Turkish and 14 Israeli populations of wild emmer wheat, based on the retrotransposon marker methods IRAP and REMAP. The level of genetic diversity we detected was in agreement with previous studies that were performed with a variety of marker systems assaying genes and other genomic components. The genetic distances failed to correlate with the geographical distances, suggesting local selection on geographically widespread haplotypes (‘weak selection’). However, the proportion of polymorphic loci correlated with the population latitude, which may reflect the temperature and water availability cline. Genetic diversity correlated with longitude, the east being more montane. Principal component analyses on the marker data separated most of the populations.Peer reviewe

Why do viruses need phloem for systemic invasion of plants ?

International audiencePlant viruses use sieve elements in phloem as the route of long-distance movement and systemic infection in plants. Plants, in turn, deploy RNA silencing, R-gene mediated defence and other mechanisms to prevent phloem transport of viruses. Cell-to-cell movement of viruses from an initially infected leaf to stem and other parts of the plant could be another possibility for systemic invasion, but it is considered to be too slow. This idea is supported by observations made on viruses that are deficient in phloem loading. The leaf abscission zone forming at the base of the petiole may constitute a barrier that prevents viral cell-to-cell movement. The abscission zone and protective layer are difficult to localize in the petiole until the leaf reaches an advanced stage of senescence. Viruses tagged with the green fluorescent protein are helpful for localization and study of the developing abscission zone

NMR metabolomics of ripened and developing oilseed rape (Brassica napus) and turnip rape (Brassica rapa)

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Triacylglycerol biosynthesis in developing Ribes nigrum and Ribes rubrum seeds from gene expression to oil composition

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