Rooting of healthy and CVC-affected 'Valência' sweet orange stem cuttings, through the use of plant regulators

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Plant growth regulators on the pre-harvest period of 'Pêra' oranges

Neste estudo, avaliou-se os efeitos de auxinas e giberelinas, combinados e aplicados em pré-colheita na qualidade interna de frutos de laranjeira Pêra. Citrus sinensis Osbeck cultivar Pêra foram pulverizadas com três aplicações, em intervalos de 45 dias, com os seguintes tratamentos: GA3 + 2,4-D a 12,5mg L-1 de cada; GA3 + 2,4-D 25mg L-1; GA3 + 2,4-D 37,5mg L-1; GA3 + NAA 12,5mg L-1;GA3 + NAA 25mg L-1; GA3 + NAA 37,5mg L-1; NAA + 2,4-D 12,5mg L-1; NAA+2,4-D 25mg L-1; NAA+2,4-D 37,5mg L-1 e testemunha (água). Os resultados mostraram que os tratamentos não prejudicaram a qualidade interna dos frutos. Além disso, os níveis de resíduo de reguladores vegetais no suco, ficaram abaixo de 0,05mg L-1, 110 dias após a última aplicação.

Enzymes in juice processing: a review

P>The use of enzymes in juice industry has contributed in increasing the yield and production of various types of juices. The addition pectinases aims in particular to degrade the pectic substances, in the cell wall and middle lamella of the cells of plants, aiming to minimise the impacts of these compounds on the characteristics of the final product, such as colour, turbidity and viscosity. Enzymes able to remove bitterness of citrus juice, extract pigments, among other applications, have also had great interest in the juice industry.

Molecular models for shikimate pathway enzymes of Xylella fastidiosa

The Xylella fastidiosa is a bacterium that is the cause of citrus variegated chlorosis (CVC). The shikimate pathway is of pivotal importance for production of a plethora of aromatic compounds in plants, bacteria, and fungi. Putative structural differences in the enzymes from the shikimate pathway, between the proteins of bacterial origin and those of plants, could be used for the development of a drug for the control of CVC. However, inhibitors for shikimate pathway enzymes should have high specificity for X. fastidiosa enzymes, since they are also present in plants. In order to pave the way for structural and functional efforts towards antimicrobial agent development, here we describe the molecular modeling of seven enzymes of the shikimate pathway of X. fastidiosa. The structural models of shikimate pathway enzymes, complexed with inhibitors, strongly indicate that the previously identified inhibitors may also inhibit the X. fastidiosa enzymes. (C) 2004 Elsevier B.V. All rights reserved.

Purification and characterization of the exopolygalacturonase produced by Aspergillus giganteus in submerged cultures

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Seasonal effects on the relationship between photosynthesis and leaf carbohydrates in orange trees

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Priority areas for the conservation of Atlantic forest large mammals

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Subcellular localization of proteins labeled with GFP in Xanthomonas citri ssp citri: targeting the division septum

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Screening of bacterial strains for pectinolytic activity: characterization of the polygalacturonase produced by Bacillus sp

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diversidade de ácaros (Acari, Arachnida) em seringueiras (Hevea brasiliensis Muell. Arg., Euphorbiaceae) na região noroeste do Estado de São Paulo, Brasil

The mites of three rubber tree cultures (Cedral, Pindorama and Taquaritinga) in order to determine the abundance of populations, the richness, the diversity and the degree of similarity among the communities was studied. Twenty one species were found, five of which were common to the three cultures. The richness and the abundance were greatest at the beginning of the dry season. The composition of communities differed probably as consequence of the kind of neighboring vegetation to each area, and because of the acaricid pulverization on the culture of Taquaritinga, reductng the richness of mite species in that area. The influence of neighboring vegetation can be shown by the occurrence of Iphiseiodes zuluagui Denmark & Muma, 1972, a common species to citrus trees, on neighboring rubber trees in Taquaritinga, and Tenuipalpus heveae Baker, 1945, a common species on rubber trees, on a coffee culture neighbor to the rubber trees of Pindorama. This data suggests that mites move among neighbor cultures, and can be an importam factor towards pest management and control. The diversity was small on the three cultures, as a result of the occurrence of one dominam species on each area, Calacarus heveae Feres, 1992 or T. heveae, which are considered pests of the rubber tree. The small diversity and the occurrence of dominant species are patterns expected in monocultures, systems with small environmental heterogeneity.

Padrão morfológico e ciclo de vida de Eutetranychus banksi (Acari: Tetranychidae) de diferentes locais e hospedeiros

Eutetranychus banksi (McGregor, 1914) is a phytophagous, polyphagous and cosmopolitan species recorded on 23 plant families in 24 countries in North, Central and South Americas, Europe, Asia, and Africa. Specimens of E. banksi present morphological variability among individuals of the same population and also among populations from different host species, being commonly referred to as a polytypic species, despite the fact that studies based on meristic comparisons of these populations are lacking. Also, there is no data available in the literature on the biological life tables of E. banksi on different hosts. Specimens collected in Brazil, Guadeloupe, Martinique, Mexico, and Paraguay were investigated in order to recognize morphological patterns among populations from different localities and hosts. A redescription of the species is provided based on data both from literature and new observations. Also, the biological cycle on three hosts, experiments of hosts exchange and the possibility of interbreeding in individuals originating from different populations were evaluated. Significant differences in the morphology of the females of different populations were detected when comparing the different hosts. The length of the dorsal pairs of setae v2, sc2, c1, c3, e1 and h1 differentiated the specimens of the populations collected from Citrus sp. from those of Hevea brasiliensis Muell. Arg. and Pachira aquatica Aubl.. Herein we observed significant variation among the life cycle of this species on the three hosts studied. When a substrate different from the one where the mites were collected was used for the biological cycle essay, significant variation was observed in several parameters such as average oviposition rate, events of arrenothoky, and sex ratio. Interbreeding with populations collected from Citrus sinensis and P. aquatica resulted in no descendants, although mating was observed.

The copper resistance operon copAB from Xanthomonas axonopodis pathovar citri: gene inactivation results in copper sensitivity

Xanthomonas axonopodis pv. citri (Xac) causes citrus canker and the completion of the Xac genome sequence has opened up the possibility of investigating basic cellular mechanisms at the genomic level. Copper compounds have been extensively used in agriculture to control plant diseases. The copA and copB genes, identified by annotation of the Xac genome, encode homologues of proteins involved in copper resistance. A gene expression assay by Northern blotting revealed that copA and copB are expressed as a unique transcript specifically induced by copper. Synthesis of the gene products was also induced by copper, reaching a maximum level at 4 h after addition of copper to the culture medium. CopA was a cytosolic protein and CopB was detected in the cytoplasmic membrane. The gene encoding CopA was disrupted by the insertion of a transposon, leading to mutant strains that were unable to grow in culture medium containing copper, even at the lowest CUSO4 concentration tested (0.25 mM), whereas the wild-type strain was able to grow in the presence of 1 mM copper. Cell suspensions of the wild-type and mutant strains in different copper concentrations were inoculated in lemon leaves to analyse their ability to induce citrus canker symptoms. Cells of mutant strains showed higher sensitivity than the wild-type strain in the presence of copper, i.e. they were not able to induce citrus canker symptoms at high copper concentrations and exhibited a more retarded growth in planta.

Crystal Structures of Xanthomonas Small Heat Shock Protein Provide a Structural Basis for an Active Molecular Chaperone Oligomer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bioassay assessment of metarhizium anisopliae (metchnikoff) sorokin (deuteromycota: hyphomycetes) against Oncometopia facialis (signoret) (hemiptera: cicadellidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Medidas da transpiração em porta-enxertos de citros

Estudou-se a variação diurna da transpiração de quatro porta -enxertos de citros, durante 12 horas, em intervalos de 60 minutos, pelo método das pesagens. Verificou-se que não ocorreu diferenças estatísticas na marcha diária da transpiração, entre Poncirus trifoliata, Citrus aurantium (laranja Azeda), Citrus sinensis (laranja Caipira) e Citrus limonia (limão Cravo). O limoeiro Cravo mostrou, nas condições estudadas, área foliar superior à Poncirus, laranja Azeda e laranja Caipira. Observou-se ainda uma correlação positiva entre a área foliar e a transpiração dos quatro porta-enxertos de citros.