Moléculas de natureza proteica sintetizadas por dois Bacillus spp. como potenciais eliciadoras de indução de resistência em tomateiro contra Xantomonas vesicatoria.

Edição dos resumos do 44º Congresso Brasileiro de Fitopatologia, 2011, Bento Gonçalves. Resumo 214

Consumo alimentar residual como índice de eficiência alimentar e suas implicações na qualidade de carne de novilhos Nelore.

A eficiência alimentar caracteriza-se como uma medida bruta obtida através da razão entre o consumo e o ganho de peso. Por ser correlacionada com peso vivo, pode apresentar limitações de utilização como parâmetro de identificação de animais eficientes por promover aumento no tamanho adulto do rebanho. Um índice alternativo de eficiência que não levaria este aumento é o Consumo Alimentar Residual (CAR). Porém, há indícios que este índice esteja associado a mudanças na composição corporal, onde os animais mais eficientes tendem a apresentar carcaças com menor espessura de gordura de acabamento e intramuscular. Este ensaio é parte do projeto ?Estratégias genéticas para melhoria da eficiência de produção e qualidade de carne bovina no Brasil? (Sistema Embrapa de Gestão - Macroprograma 1), no qual em três anos serão avaliados geneticamente 800 novilhos, filhos de 30 touros selecionados do sumário Nacional de Touros da raça Nelore. O objetivo desta proposta será avaliar, em dois anos, as relações entre CAR, características de carcaça e qualidade de carne de 300 novilhos Nelore. Em cada ano serão confinados 150 novilhos castrados, com 18 meses de idade. A dieta irá conter 14,7% de proteína bruta e 74,1% de nutrientes digestíveis totais. Serão avaliados consumo, ganho de peso, CAR, características de carcaça, qualidade de carne e as respectivas correlações fenotípicas. Todas as mensurações de desempenho animal e de qualidade de carne serão avaliadas mediante análise de variância. As médias obtidas nas classes de CAR (alto, médio ou baixo) serão comparadas pelo teste de Tukey a 5% de probabilidade. Os coeficientes de correlação entre as variáveis serão obtidos através do procedimento CORR do SAS (2002). Espera-se que o CAR possa ser utilizado como ferramenta para permitir a seleção de animais eficientes sem comprometer a qualidade da carne

In-depth genome characterization of a Brazilian common bean core collection using DArTseq high-density SNP genotyping

Background: Common bean is a legume of social and nutritional importance as a food crop, cultivated worldwide especially in developing countries, accounting for an important source of income for small farmers. The availability of the complete sequences of the two common bean genomes has dramatically accelerated and has enabled new experimental strategies to be applied for genetic research. DArTseq has been widely used as a method of SNP genotyping allowing comprehensive genome coverage with genetic applications in common bean breeding programs. Results: Using this technology, 6286 SNPs (1 SNP/86.5 Kbp) were genotyped in genic (43.3%) and non-genic regions (56. 7%). Genetic subdivision associated to the common bean gene pools (K = 2) and related to grain types (K = 3 and K = 5) were reported. A total of 83% and 91% of all SNPs were polymorphic within the Andean and Mesoamerican gene pools, respectively, and 26% were able to differentiate the gene pools. Genetic diversity analysis revealed an average HE of 0.442 for the whole collection, 0.102 for Andean and 0.168 for Mesoamerican gene pools (FST = 0.747 between gene pools), 0. 440 for the group of cultivars and lines, and 0.448 for the group of landrace accessions (FST = 0.002 between cultivar/line and landrace groups). The SNP effects were predicted with predominance of impact on non-coding regions (77.8%). SNPs under selection were identified within gene pools comparing landrace and cultivar/line germplasm groups (Andean: 18; Mesoamerican: 69) and between the gene pools (59 SNPs), predominantly on chromosomes 1 and 9. The LD extension estimate corrected for population structure and relatedness (r2 SV) was~88 kbp, while for the Andean gene pool was~395 kbp, and for the Mesoamerican was ~ 130 kbp. Conclusions: For common bean, DArTseq provides an efficient and cost-effective strategy of generating SNPs for large-scale genome-wide studies. The DArTseq resulted in an operational panel of 560 polymorphic SNPs in linkage equilibrium, providing high genome coverage. This SNP set could be used in genotyping platforms with many applications, such as population genetics, phylogeny relation between common bean varieties and support to molecular breeding approaches

Evolutionary and Experimental Assessment of Novel Markers for Detection of Xanthomonas euvesicatoria in Plant Samples

BACKGROUND: Bacterial spot-causing xanthomonads (BSX) are quarantine phytopathogenic bacteria responsible for heavy losses in tomato and pepper production. Despite the research on improved plant spraying methods and resistant cultivars, the use of healthy plant material is still considered as the most effective bacterial spot control measure. Therefore, rapid and efficient detection methods are crucial for an early detection of these phytopathogens. METHODOLOGY: In this work, we selected and validated novel DNA markers for reliable detection of the BSX Xanthomonas euvesicatoria (Xeu). Xeu-specific DNA regions were selected using two online applications, CUPID and Insignia. Furthermore, to facilitate the selection of putative DNA markers, a customized C program was designed to retrieve the regions outputted by both databases. The in silico validation was further extended in order to provide an insight on the origin of these Xeu-specific regions by assessing chromosomal location, GC content, codon usage and synteny analyses. Primer-pairs were designed for amplification of those regions and the PCR validation assays showed that most primers allowed for positive amplification with different Xeu strains. The obtained amplicons were labeled and used as probes in dot blot assays, which allowed testing the probes against a collection of 12 non-BSX Xanthomonas and 23 other phytopathogenic bacteria. These assays confirmed the specificity of the selected DNA markers. Finally, we designed and tested a duplex PCR assay and an inverted dot blot platform for culture-independent detection of Xeu in infected plants. SIGNIFICANCE: This study details a selection strategy able to provide a large number of Xeu-specific DNA markers. As demonstrated, the selected markers can detect Xeu in infected plants both by PCR and by hybridization-based assays coupled with automatic data analysis. Furthermore, this work is a contribution to implement more efficient DNA-based methods of bacterial diagnostics