摘要
Disease-resistant genes play an important role in defending against a variety of pathogens and insect pests in plants. Most of the disease-resistant genes encode pro- teins with conserved leucine rich repeat and nucleotide binding site domains. In this study, we cloned and char- acterized gene-resistant analogs (RGAs) from Eucalyptus grandis using degenerate PCR, with primers specifically targeting these two domains. The amplified fragments were cloned into the pGEM-T vector and transformed into Escherichia coli. Among the 90 clones obtained, 13 were sequenced and compared with each other and with previ- ously identified gene-resistant diseases. A BLASTX search in GenBank revealed high similarities among the con- served domains of these cloned genes with RGA genes. Some clones, however, showed no significant similarity with DNA sequences in GenBank. Southern blotting ana- lysis identified several polymorphic RFLP loci between distinct genotypes. However, none of them co-segregated with the Puccinia psidii Winter resistance gene 1 (Ppr1) in a population study.
Disease-resistant genes play an important role in defending against a variety of pathogens and insect pests in plants. Most of the disease-resistant genes encode pro- teins with conserved leucine rich repeat and nucleotide binding site domains. In this study, we cloned and char- acterized gene-resistant analogs (RGAs) from Eucalyptus grandis using degenerate PCR, with primers specifically targeting these two domains. The amplified fragments were cloned into the pGEM-T vector and transformed into Escherichia coli. Among the 90 clones obtained, 13 were sequenced and compared with each other and with previ- ously identified gene-resistant diseases. A BLASTX search in GenBank revealed high similarities among the con- served domains of these cloned genes with RGA genes. Some clones, however, showed no significant similarity with DNA sequences in GenBank. Southern blotting ana- lysis identified several polymorphic RFLP loci between distinct genotypes. However, none of them co-segregated with the Puccinia psidii Winter resistance gene 1 (Ppr1) in a population study.
基金
the Suzano Celulose S/A for logistical support
the‘‘Conselho Nacional de Desenvolvimento Científico e Tecnológico’’(CNPq)
the‘‘Coordenao de Aperfeioamento de Pessoal de Nível Superior’’(CAPES)
the‘‘Fundao de Amparo à Pesquisa do Estado de Minas Gerais’’(FAPEMIG)for financial support to this study