Molecular characterization of the Rpv3 locus towards the development of KASP markers for downy mildew resistance in grapevine (Vitis spp.).

Plasmopara viticola is the oomycete that causes downy mildew in grapevines. Varying levels of resistance to P. viticola across grape cultivars allowed quantitative trait loci to be identified. The Rpv3 locus is located at chromosome 18, in a region enriched in TIR-NBS-LRR genes, and the phenotype associated is a high hypersensitive response. In this work, we aimed to identify candidate genes associated with resistance to downy mildew on the Rpv3 locus and to evaluate their transcriptional profiles in a susceptible and a resistant grapevine cultivar after challenging with P. viticola. Candidate genes were identified by in silico functional enrichment tests. Many predicted genes associated with resistance to diseases were found at the Rpv3 locus. In total, seventeen genes were evaluated by RT-qPCR. Differences in the steadystate expression of these genes were observed between the two cultivars. Four genes were found to be expressed only in Villard Blanc, suggesting their association to the hypersensitivity reaction. Aiming to assist marker assisted-selection for downy mildew resistance, we show the efficient use of a set of SSR markers. Furthermore, from on a set of forty-one Rpv3-located SNPs, whose segregation was tested in the populations studied, the two segregating markers, Rpv3_15 and Rpv3_33, were considered efficient for downy mildew resistance identification. This study presents a genomic characterization of the Rpv3 locus, confirms its involvement in resistance against P. viticola infection and presents promising biotechnological tools for the selection of young resistant individuals.Na publicação: Roberto Togawa

Molecular phylogeny of the subfamily Stevardiinae Gill, 1858 (Characiformes: Characidae): classification and the evolution of reproductive traits

Abstract Background The subfamily Stevardiinae is a diverse and widely distributed clade of freshwater fishes from South and Central America, commonly known as “tetras” (Characidae). The group was named “clade A” when first proposed as a monophyletic unit of Characidae and later designated as a subfamily. Stevardiinae includes 48 genera and around 310 valid species with many species presenting inseminating reproductive strategy. No global hypothesis of relationships is available for this group and currently many genera are listed as incertae sedis or are suspected to be non-monophyletic. Results We present a molecular phylogeny with the largest number of stevardiine species analyzed so far, including 355 samples representing 153 putative species distributed in 32 genera, to test the group’s monophyly and internal relationships. The phylogeny was inferred using DNA sequence data from seven gene fragments (mtDNA: 12S, 16S and COI; nuclear: RAG1, RAG2, MYH6 and PTR). The results support the Stevardiinae as a monophyletic group and a detailed hypothesis of the internal relationships for this subfamily. Conclusions A revised classification based on the molecular phylogeny is proposed that includes seven tribes and also defines monophyletic genera, including a resurrected genus Eretmobrycon, and new definitions for Diapoma, Hemibrycon, Bryconamericus sensu stricto, and Knodus sensu stricto, placing some small genera as junior synonyms. Inseminating species are distributed in several clades suggesting that reproductive strategy is evolutionarily labile in this group of fishes.http://deepblue.lib.umich.edu/bitstream/2027.42/134621/1/12862_2015_Article_403.pd