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Abstract(s)
Os Oomicetas estĆ£o entre os organismos que causam doenƧas graves nas plantas e importantes perdas econĆ³micas na agricultura. SĆ£o um grupo diverso de organismos eucariotas que podem encontrar-se em muitos nichos ecolĆ³gicos, incluindo saprĆ³fitas e parasitas de plantas e animais.
Phytophthora cinnamomi Ć© um Oomiceta, considerado um dos patogĆ©neos mais difundidos e destrutivos do planeta. A sua presenƧa geogrĆ”fica Ć© cosmopolita e a gama de hospedeiros Ć© encarada como uma das maiores. Este patogĆ©neo causa danos econĆ³micos enormes a importantes culturas a nĆvel mundial, isto contribuiu para despertar a atenĆ§Ć£o da comunidade cientĆfica. Ć o agente causal da doenƧa da ātintaā do castanheiro (Castanea sativa Miller).
Em Portugal, o castanheiro ocupa sobretudo a parte mais montanhosa do interior Centro e Norte, sendo uma importante fonte de rendimento das populaƧƵes. O castanheiro tem diferentes aplicaƧƵes, para alĆ©m da castanha e da madeira, possuĆ um papel importante na ecologia dos solos e na biodiversidade. Por isso, Ć© importante conhecer os mecanismos moleculares (genes e proteĆnas) que estĆ£o na base do processo infeccioso de Castanea sativa por Phytophthora cinnamomi e a natureza da interaĆ§Ć£o patogĆ©neo-hospedeiro a fim de se poderem estabelecer estratĆ©gias de combate e controlo deste parasita. Com ferramentas de bioinformĆ”tica, conseguimos identificar e caracterizar o gene Avr3a em sequĆŖncias genĆ³micas de P. cinnamomi, depositadas nas Databases. Este gene codifica uma proteĆna com 209 aa reconhecida no citoplasma do hospedeiro onde desencadeia morte celular. Neste trabalho tambĆ©m caraterizamos duas sequĆŖncias no genoma de P. cinnamomi que codificam proteĆnas de 309 e 425 aa, com atividade lipĆ”sica e com localizaĆ§Ć£o extracelular, homĆ³logas com proteĆnas de papel significativo na patogenicidade de fungos de diferentes espĆ©cies do gĆ©nero Phytophthora. A fim de compreender melhor o seu papel no mecanismo de patogenicidade, foram desenhadas cassetes de silenciamento por ARN de interferĆŖncia para os genes que codificam estas proteĆnas.
Oomycetes are among the organisms that cause serious diseases in plants and significant economic losses in agriculture. They are a diverse group of eukaryotic organisms that can be found in many ecological niches, including saprophytes and plant and animal parasites. Phytophthora cinnamomi is an Oomycete considered one of the most widespread and destructive pathogens on the planet. Its geographic presence is cosmopolitan and the range of hosts is regarded as one of the largest. This pathogen causes enormous economic damages to important cultures worldwide, this has helped to attract the attention of the scientific community. It is the causal agent of chestnut "ink" disease (Castanea sativa Miller). In Portugal, the chestnut tree occupies mainly the hilly part of the interior of the Center and North, being an important source of income of the populations. The chestnut tree has different applications, besides chestnut and wood, it plays an important role in soil ecology and biodiversity. Therefore it is important to know the molecular mechanisms (genes and proteins) that are the basis of the Castanea sativa infestation process by Phytophthora cinnamomi and the nature of the pathogen-host interaction in order to establish strategies to combat and control this parasite. With bioinformatics tools, we were able to identify and characterize the Avr3a gene in genomic sequences of P. cinnamomi deposited in the Databases. This gene encodes a recognized 209 aa protein in the host cytoplasm where it triggers cell death. In this work we also characterize two sequences in the genome of P. cinnamomi that encode proteins of 309 and 425 aa with lipase activity and with extracellular localization, homologues with proteins with significant role in the pathogenicity of fungi of different species of the genus Phytophthora. In order to better understand their role in the pathogenicity mechanism, interference RNA silencing cassettes were designed for the genes encoding these proteins.
Oomycetes are among the organisms that cause serious diseases in plants and significant economic losses in agriculture. They are a diverse group of eukaryotic organisms that can be found in many ecological niches, including saprophytes and plant and animal parasites. Phytophthora cinnamomi is an Oomycete considered one of the most widespread and destructive pathogens on the planet. Its geographic presence is cosmopolitan and the range of hosts is regarded as one of the largest. This pathogen causes enormous economic damages to important cultures worldwide, this has helped to attract the attention of the scientific community. It is the causal agent of chestnut "ink" disease (Castanea sativa Miller). In Portugal, the chestnut tree occupies mainly the hilly part of the interior of the Center and North, being an important source of income of the populations. The chestnut tree has different applications, besides chestnut and wood, it plays an important role in soil ecology and biodiversity. Therefore it is important to know the molecular mechanisms (genes and proteins) that are the basis of the Castanea sativa infestation process by Phytophthora cinnamomi and the nature of the pathogen-host interaction in order to establish strategies to combat and control this parasite. With bioinformatics tools, we were able to identify and characterize the Avr3a gene in genomic sequences of P. cinnamomi deposited in the Databases. This gene encodes a recognized 209 aa protein in the host cytoplasm where it triggers cell death. In this work we also characterize two sequences in the genome of P. cinnamomi that encode proteins of 309 and 425 aa with lipase activity and with extracellular localization, homologues with proteins with significant role in the pathogenicity of fungi of different species of the genus Phytophthora. In order to better understand their role in the pathogenicity mechanism, interference RNA silencing cassettes were designed for the genes encoding these proteins.
Description
Keywords
Castanheiro Phytophthora cinnamomi DoenƧa da tinta Lipases Gene Avr3a ARN de interferĆŖncia