Analysis of the relationship between grapevine cultivars, sports and clones via DNA fingerprinting

DNA fingerprinting utilizing RAPD polymorphisms was employed to investigate the relationship among 16 grapevine cultivars and sports thought to have arisen from these cultivars. From 53 primers, a total of 464 bands were generated, of which 29 % were common to all genotypes tested. Cluster analysis classified all tested cultivars into two main groups (Vitis vinifera L. and V. x Labruscana Bailey) as expected. No polymorphism was detected among known clones of Chardonnay (Ch. clone 7, Ch. clone 78 and Ch. Geneva clone) or Pinot noir (P. n. clone 29, P. n. Geneva clone and P. n. Pernand). Pinot Meunier, Pinot gris, and Gamay Beaujolais displayed patterns indistinguishable from Pinot noir. Auxerrois and Melon showed unique patterns and may be classified as distinct cultivars. Chardonnay clone 7 shared 84 % of its bands with Pinot noir. There was more than 97 % RAPD amplicon homology between Niagara and two supposed sports, and between Concord and a red-fruited sport. Taking into account the error rate in scoring RAPD bands, the evidence is against the hypothesis that the three sports are distinct cultivars. While RAPD banding patterns could not distinguish between known clones, they were useful for distinguishing between phenotypically similar cultivars and for assessing the origins of cultivars thought to have originated as sports

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Whole-Genome Expression Profiling Defines the HrpL Regulon of \u3ci\u3ePseudomonas syringae\u3c/i\u3e pv. \u3ci\u3etomato\u3c/i\u3e DC3000, Allows de novo Reconstruction of the Hrp \u3ci\u3ecis\u3c/i\u3e Element, and Identifies Novel Coregulated Genes

Pseudomonas syringae pv. tomato DC3000 is a model pathogen of tomato and Arabidopsis that uses a hypersensitive response and pathogenicity (Hrp) type III secretion system (T3SS) to deliver virulence effector proteins into host cells. Expression of the Hrp system and many effector genes is activated by the HrpL alternative sigma factor. Here, an open reading frame-specific whole-genome microarray was constructed for DC3000 and used to comprehensively identify genes that are differentially expressed in wild-type and ΔhrpL strains. Among the genes whose differential regulation was statistically significant, 119 were upregulated and 76 were downregulated in the wild-type compared with the ΔhrpL strain. Hierarchical clustering revealed a subset of eight genes that were upregulated particularly rapidly. Gibbs sampling of regions upstream of HrpL-activated operons revealed the Hrp promoter as the only identifiable regulatory motif and supported an iterative refinement involving real-time polymerase chain reaction testing of additional HrpL-activated genes and refinements in a hidden Markov model that can be used to predict Hrp promoters in P. syringae strains. This iterative bioinformatic-experimental approach to a comprehensive analysis of the HrpL regulon revealed a mix of genes controlled by HrpL, including those encoding most type III effectors, twin-arginine transport (TAT) substrates, other regulatory proteins, and proteins involved in the synthesis or metabolism of phytohormones, phytotoxins, and myo-inositol. This analysis provides an extensively verified, robust method for predicting Hrp promoters in P. syringae genomes, and it supports subsequent identification of effectors and other factors that likely are important to the host-specific virulence of P. syringae