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Brasília, Brazil

Resende M.F.R.,University of Florida | Munoz P.,University of Florida | Acosta J.J.,University of Florida | Peter G.F.,University of Florida | And 6 more authors.
New Phytologist

• Genomic selection is increasingly considered vital to accelerate genetic improvement. However, it is unknown how accurate genomic selection prediction models remain when used across environments and ages. This knowledge is critical for breeders to apply this strategy in genetic improvement. • Here, we evaluated the utility of genomic selection in a Pinus taeda population of c. 800 individuals clonally replicated and grown on four sites, and genotyped for 4825 single-nucleotide polymorphism (SNP) markers. Prediction models were estimated for diameter and height at multiple ages using genomic random regression best linear unbiased predictor (BLUP). • Accuracies of prediction models ranged from 0.65 to 0.75 for diameter, and 0.63 to 0.74 for height. The selection efficiency per unit time was estimated as 53-112% higher using genomic selection compared with phenotypic selection, assuming a reduction of 50% in the breeding cycle. Accuracies remained high across environments as long as they were used within the same breeding zone. However, models generated at early ages did not perform well to predict phenotypes at age 6yr. • These results demonstrate the feasibility and remarkable gain that can be achieved by incorporating genomic selection in breeding programs, as long as models are used at the relevant selection age and within the breeding zone in which they were estimated. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust. Source

Komiya R.,National Institute of Genetics NIG | Komiya R.,Okinawa Institute of Science and Technology | Ohyanagi H.,Plant Genetics Laboratory | Ohyanagi H.,Mitsubishi Group | And 7 more authors.
Plant Journal

Small RNAs that interact with Argonaute (AGO) proteins play central roles in RNA-mediated silencing. MEIOSIS ARRESTED AT LEPTOTENE1 (MEL1), a rice AGO, has specific functions in the development of pre-meiotic germ cells and the progression of meiosis. Here, we show that MEL1, which is located mostly in the cytoplasm of germ cells, associates preferentially with 21-nucleotide phased small interfering RNAs (phasiRNAs) that bear a 5′-terminal cytosine. Most phasiRNAs are derived from 1171 intergenic clusters distributed on all rice chromosomes. From these clusters, over 700 large intergenic, non-coding RNAs (lincRNAs) that contain the consensus sequence complementary to miR2118 are transcribed specifically in inflorescences, and cleaved within the miR2118 site. Cleaved lincRNAs are processed via DICER-LIKE4 (DCL4) protein, resulting in production of phasiRNAs. This study provides the evidence that the miR2118-dependent and the DCL4-dependent pathways are both required for biogenesis of 21-nt phasiRNAs associated with germline-specific MEL1 AGO in rice, and over 700 lincRNAs are key factors for induction of this biogenesis during reproductive-specific stages. © 2014 John Wiley & Sons Ltd. Source

Neves L.G.,Plant Genetics Laboratory | Neves L.G.,Federal University of Vicosa | Neves L.G.,University of Florida | MC Mamani E.,Plant Genetics Laboratory | And 5 more authors.
BMC Genomics

Background: Technological advances are progressively increasing the application of genomics to a wider array of economically and ecologically important species. High-density maps enriched for transcribed genes facilitate the discovery of connections between genes and phenotypes. We report the construction of a high-density linkage map of expressed genes for the heterozygous genome of Eucalyptus using Single Feature Polymorphism (SFP) markers.Results: SFP discovery and mapping was achieved using pseudo-testcross screening and selective mapping to simultaneously optimize linkage mapping and microarray costs. SFP genotyping was carried out by hybridizing complementary RNA prepared from 4.5 year-old trees xylem to an SFP array containing 103,000 25-mer oligonucleotide probes representing 20,726 unigenes derived from a modest size expressed sequence tags collection. An SFP-mapping microarray with 43,777 selected candidate SFP probes representing 15,698 genes was subsequently designed and used to genotype SFPs in a larger subset of the segregating population drawn by selective mapping. A total of 1,845 genes were mapped, with 884 of them ordered with high likelihood support on a framework map anchored to 180 microsatellites with average density of 1.2 cM. Using more probes per unigene increased by two-fold the likelihood of detecting segregating SFPs eventually resulting in more genes mapped. In silico validation showed that 87% of the SFPs map to the expected location on the 4.5X draft sequence of the Eucalyptus grandis genome.Conclusions: The Eucalyptus 1,845 gene map is the most highly enriched map for transcriptional information for any forest tree species to date. It represents a major improvement on the number of genes previously positioned on Eucalyptus maps and provides an initial glimpse at the gene space for this global tree genome. A general protocol is proposed to build high-density transcript linkage maps in less characterized plant species by SFP genotyping with a concurrent objective of reducing microarray costs. HIgh-density gene-rich maps represent a powerful resource to assist gene discovery endeavors when used in combination with QTL and association mapping and should be especially valuable to assist the assembly of reference genome sequences soon to come for several plant and animal species. © 2011 Neves et al; licensee BioMed Central Ltd. Source

Faria D.A.,Plant Genetics Laboratory | Faria D.A.,Catholic University of Brasilia | Mamani E.M.C.,Plant Genetics Laboratory | Mamani E.M.C.,University of Brasilia | And 5 more authors.
Tree Genetics and Genomes

Eucalypts are keystone species in their natural ranges and are extensively planted worldwide for high-quality woody biomass. A novel set of 21 polymorphic and interspecifically transferable microsatellite markers based on tetra-, penta- and hexanucleotide repeats were developed and tested for high-precision genotyping of species of Eucalyptus. These microsatellites were characterized in population samples of four species, Eucalyptus grandis, Eucalyptus globulus, Eucalyptus urophylla, and Eucalyptus camaldulensis, representing three phylogenetic sections of subgenus Symphyomyrtus. These markers provide a clear advantage for accurate allele calling due to their larger allele size difference. Two multiplexed microsatellite combinations, a 14-locus/four-dye and an 18-locus/five-dye set, analyzable in single lanes were designed, providing resolution and throughput analogous to those routinely used in human DNA profiling. This set of microsatellites was shown to have high resolution for clone fingerprinting, inter-individual genetic distance estimation, species distinction, and assignment of hybrid individuals to their most likely ancestral species. These systems will be particularly useful for comparative population genetics and molecular breeding applications that require consistent allele calling across different points in time or laboratories. © 2010 Springer-Verlag. Source

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