The genus Xanthomonas is a diverse and economically important group of bacterial phytopathogens, belonging to the gamma-subdivision of the Proteobacteria. Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, which affects most commercial citrus cultivars, resulting in significant losses worldwide. Symptoms include canker lesions, leading to abscission of fruit and leaves and general tree decline. Xanthomonas campestris pv. campestris (Xcc) causes black rot, which affects crucifers such as Brassica and Arabidopsis. Symptoms include marginal leaf chlorosis and darkening of vascular tissue, accompanied by extensive wilting and necrosis. Xanthomonas campestris pv. campestris is grown commercially to produce the exopolysaccharide xanthan gum, which is used as a viscosifying and stabilizing agent in many industries. Here we report and compare the complete genome sequences of Xac and Xcc. Their distinct disease phenotypes and host ranges belie a high degree of similarity at the genomic level. More than 80% of genes are shared, and gene order is conserved along most of their respective chromosomes. We identified several groups of strain-specific genes, and on the basis of these groups we propose mechanisms that may explain the differing host specificities and pathogenic processes.

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Crystallization and preliminary X-ray diffraction analysis of XAC1151, a small heat-shock protein from Xanthomonas axonopodis pv. The hspA gene (XAC1151) from Xanthomonas axonopodis pv. citri encodes a protein of 158 amino acids that belongs to the small heat-shock protein (sHSP) family of proteins. These proteins function as molecular chaperones by preventing protein aggregation. The protein was crystallized using the sittingdrop vapour-diffusion method in the presence of ammonium phosphate. X-ray diffraction data were collected to 1.65 Å resolution using a synchrotronradiation source. The crystal belongs to the rhombohedral space group R3, with unit-cell parameters a = b = 128.7, c = 55.3 Å . The crystal structure was solved by molecular-replacement methods. Structure refinement is in progress.

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Aiming to evaluate the potential wood energy of three clones of eucalyptus in different planting spacings, was installed an experiment with a randomized block design in a factorial design, with a combination of six spacings (2,5 x 0,5 m; 2,5 x 1,0 m; 2,5 x 2,0 m; 3,0 x 0,5 m; 3,0 x 1,0 m e 3,0 x 2,0 m) three eucalyptus clones (GG 157, GG 680 e GG 100), with three replicates. At 32 months old, was selected and cut down a medium-diameter tree per plot. These trees were scaled by Smalian method, using sections from 2.0 m to DAP. On these sections were removed wooden disks with 5.0 cm thick, which were used for the analyzes of basic density and calorific value of wood and, based on these values, it was possible to estimate the amount of energy stored per m³. It was observed that the basic density of wood, the gross calorific power and the energy stored in eucalyptus wood were different with the clones and planting spacing. Basic density and the amount of energy stored in a cubic meter of eucalyptus wood tended to increase with in the planting spacing, mainly for GG 680 and GG100 clones. The superior gross calorific of the wood showed no direct relationship with the planting density.

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-The present study aimed to determine the curves of macronutrients and dry matter accumulation in grain sorghum DKB 599, grown in a semiarid region. A field experiment was conducted on a sandy loam eutrophic red Latosol (Oxisol) in Janaúba, State of Minas Gerais (MG), Brazil, in a randomized block design with four replications.As statistical method, a nonlinear regression, sigmoidal function with three parameters was used. After drying, the plants were weighed and ground to determine N, P, K, Ca, Mg and S concentration. Grain sorghum plants accumulate nutrients in their shoots in the following order: N> K> Ca> P> Mg> S. The highest concentrations of K and N were observed in stems and grains, respectively. In the conditions of this experiment, the most favorable time to perform nitrogen and potassium topdressing fertilization is when the plants present seven fully expanded leaves or 24 days after the emergency (DAE).Keywords: fertilization, growth, nutrition, Sorghum bicolor. ABSORÇÃO DE MACRONUTRIENTES E ACÚMULO DE MATÉRIA SECA NO SORGO GRANÍFERORESUMO -Este trabalho teve como objetivo determinar as curvas de acúmulo de matéria seca e macronutrientes no sorgo DKB 599 cultivado em região semiárida. O experimento foi conduzido em campo sobre um Latossolo Vermelho eutrófico, de textura franco-argilosa, no município de Janaúba-MG, Brasil, em delineamento experimental de blocos casualizados, com quatro repetições. Utilizou-se o modelo de regressão não linear, função sigmoidal com três parâmetros como método estatístico. Após secagem, cada parte da planta foi pesada e moída para, em seguida, determinarem-se os teores de N, P, K, Ca, Mg e S. As plantas de sorgo granífero acumulam nutrientes em sua parte aérea na seguinte ordem: N > K > Ca > P > Mg > S. As maiores concentrações de K e N foram observadas, respectivamente, nos caules e nos grãos. Nas condições de condução do experimento, a época mais propícia para realizar a adubação nitrogenada e potássica em cobertura é quando as plantas apresentam sete folhas totalmente expandidas ou 24 dias após a emergência (DAE).Palavras-chave: fertilização, crescimento, nutrição, Sorghum bicolor.

Paracoccidioides brasiliensis isolates are not homogeneous in their patterns of pathogenicity in animals and adhesion to epithelial cells. During this investigation, genotypic differences were observed between two samples of P. brasiliensis strain 18 yeast phase (Pb18) previously cultured many times, one taken before (Pb18a) and the other after (Pb18b) animal inoculation. Random amplified polymorphic DNA analysis using the primer OPJ4 distinguished Pb18b from Pb18a by one 308 bp DNA fragment, which after cloning and sequencing was shown to encode a polypeptide sequence homologous to the protein b-adaptin. It is suggested, by comparison to other micro-organisms, that this protein might play an important role in the virulence of P. brasiliensis. This result demonstrates the influence of in vitro subculturing on the genotype of this organism.