Novel insights into the genomic basis of citrus canker based on the genome sequences of two strains of Xanthomonas fuscans subsp. aurantifolii

Background: Citrus canker is a disease that has severe economic impact on the citrus industry worldwide. There are three types of canker, called A, B, and C. The three types have different phenotypes and affect different citrus species. The causative agent for type A is Xanthomonas citri subsp. citri, whose genome sequence was made available in 2002. Xanthomonas fuscans subsp. aurantifolii strain B causes canker B and Xanthomonas fuscans subsp. aurantifolii strain C causes canker C. Results: We have sequenced the genomes of strains B and C to draft status. We have compared their genomic content to X. citri subsp. citri and to other Xanthomonas genomes, with special emphasis on type III secreted effector repertoires. In addition to pthA, already known to be present in all three citrus canker strains, two additional effector genes, xopE3 and xopAI, are also present in all three strains and are both located on the same putative genomic island. These two effector genes, along with one other effector-like gene in the same region, are thus good candidates for being pathogenicity factors on citrus. Numerous gene content differences also exist between the three cankers strains, which can be correlated with their different virulence and host range. Particular attention was placed on the analysis of genes involved in biofilm formation and quorum sensing, type IV secretion, flagellum synthesis and motility, lipopolysacharide synthesis, and on the gene xacPNP, which codes for a natriuretic protein. Conclusion: We have uncovered numerous commonalities and differences in gene content between the genomes of the pathogenic agents causing citrus canker A, B, and C and other Xanthomonas genomes. Molecular genetics can now be employed to determine the role of these genes in plant-microbe interactions. The gained knowledge will be instrumental for improving citrus canker control.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientIfico e Tecnologico (CNPq)Coordenacao para Aperfeicoamento de Pessoal de Ensino Superior (CAPES)Fundo de Defesa da Citricultura (FUNDECITRUS

Micoses superficiais na cidade de Manaus, AM, entre março e novembro/2003 Superficial mycoses in the City of Manaus/AM between March and November/2003

FUNDAMENTOS: Micoses superficiais estritas são infecções fúngicas que se localizam nas camadas superficiais da pele e seus anexos. As micoses superficiais cutâneas representadas pelas dermatofitoses e candidíases podem ultrapassar a camada córnea da pele. Na região amazônica possuem incidência elevada. OBJETIVOS: Estudar as micoses superficiais, estritas e cutâneas, diagnosticadas sob o ponto de vista epidemiológico e micológico. PACIENTES E MÉTODOS: Pacientes com suspeita clínica de micoses superficiais submetidos a exame micológico no período de março a novembro de 2003 no Laboratório de Micologia Médica/CPCS/INPA. RESULTADOS: Foram realizados 394 exames, tendo 256 apresentado diagnóstico positivo. As micoses mais incidentes foram onicomicoses (135) e pitiríase versicolor (98). Malassezia spp. (77) e Candida spp. (72) foram os agentes fúngicos mais isolados. Tinea capitis apresentou maior ocorrência nos pré-escolares (3), e onicomicoses em adultos (94). O sexo feminino foi o mais acometido (91). Todas as classes sociais foram infectadas, com predominância da C (37). CONCLUSÃO: Onicomicoses e pitiríase versicolor acometeram sobretudo adultos. A Tinea capitis ocorre principalmente, em crianças. As micoses superficiais apresentaram mais incidentes nas mulheres. Malassezia spp. e Candida spp. foram os agentes mais isolados.<br>BACKGROUND - Restricted superficial mycoses are fungal infections that appear on the skin superficial layers and their adnexa. However skin superficial mycoses represented by dermatophytoses and candidiasis can invade the corneal layer. This type of mycosis has a high incidence in the Amazon region. OBJECTIVES - To study the restricted superficial mycoses under the epidemiological and mycological point of view. PATIENTS AND METHODS - Patients presenting clinical suspicion of superficial mycoses submitted to mycological examination from March to November 2003 at the Clinical Mycology Laboratory/CPCS-INPA. RESULTS - Three hundred and ninety-four examinations were carried out throughout the period and 256 were positive. The mycoses with higher incidence were onychomycosis (135) and pityriasis versicolor (98). The most often isolated agents were Malassezia spp. (77) and Candida spp. (72). Tinea capitis was more frequent in pre-school children (3) and onychomycosis in adults (94). Mycoses were more prevalent in women (91). All socioeconomic classes were affected, with a predominance in class C (37). CONCLUSION - Onychomycosis and pityriasis versicolor affected mostly adults and Tinea capitis occured mainly in children. Superficial mycoses were more predominant in women. Malassezia spp. and Candida spp. were the most often isolated agents