ABSTRACT
Eucalyptus scab and shoot malformation caused by Elsinoë necatrix is an emerging disease and a serious threat to the global commercial forestry industry. The disease was first discovered in North Sumatra, Indonesia and now requires a simple and effective method for early pathogen detection. In this study, a rapid and sensitive Loop-mediated isothermal amplification (LAMP) assay was developed for E. necatrix. A unique region in a secondary metabolite gene cluster was used as target for the assay. To test robustness of the assay, LAMP amplification was verified in 15 strains of E. necatrix. A specificity test against 23 closely related Elsinoë species and three fungal species commonly isolated on Eucalyptus showed that the LAMP assay exclusively identified E. necatrix isolates. The assay had a high level of sensitivity, able to detect 0.01 ng (approximately 400 target copies) of pure E. necatrix DNA. Furthermore, using a simple DNA extraction method, it was possible to use this assay to detect E. necatrix in infected Eucalyptus leaves.
ABSTRACT
Características oligogênicas de distribuição discreta e expressão governada por poucos genes de maior efeito têm se mostrado importantes na condução dos programas de melhoramento, com destaque para a resposta de resistência das plantas às doenças. Métodos tradicionais de detecção de QTL's, que pressupõem normalidade e herança governada por múltiplos fatores, não deveriam ser utilizados para mapeamento dessas características de distribuição discreta e interação epistática predominante. O objetivo deste trabalho é avaliar os resultados de um método para mapeamento e detecção de locos controladores da expressão de características oligogênicas, OTL's (Oligogenic Trait Loci). Esse método, definido como MMCO (Método de Mapeamento de Características Oligogênicas), utiliza funções de verossimilhança para obtenção de estimativas de ligação fatorial entre locos marcadores e locos controladores de características oligogênicas. Os resultados indicam que o método foi adequado para detecção de OTL's em populações F2 relativamente pequenas, compostas por 200 indivíduos, e que a determinação a priori do padrão de herança é condição necessária para a utilização dessa estratégia, que se diferencia por atender as pressuposições de análise, não necessitar de informação prévia de ordenamento entre as marcas e por permitir a obtenção de estimativas a partir da informação contida em todas as classes genotípicas.
Oligogenic traits are distinguished by their heritage ruled by higher effect genes and by their importance for cultivated plants, with emphasis to the plant disease resistance inheritance. The qualitative nature and epistatic interaction of these traits results in a heritage pattern that should not be interpreted through traditional QTL detection strategies. The objective of this work was to propose a method for Oligogenic Traits Loci (OTL) detection. This method, defined as Oligogenic Trait Mapping Method (OTMM) uses maximum likehood probability functions to obtain adjusted "r" estimates that express the distance among the molecular markers and the OTL loci. The results show that the method was adequate for OTL detection even in relatively small F2 populations. The prior definition of the oligogenic heritage pattern is one the main requirements of this method that focus in the attainment of the analysis presumptions without previous markers order information.
ABSTRACT
We characterized indigenous common bean rhizobia from five districts of the state of Minas Gerais, Brazil. The isolates were trapped by two common bean varieties, the Mineiro Precoce (Andean origin) and Ouro Negro (Mesoamerican origin). Analysis by BOX-PCR of selected isolates detected a high level of genetic diversity.
Subject(s)
Genetic Variation , In Vitro Techniques , Polymerase Chain Reaction , Phaseolus nanus/isolation & purification , Rhizobium/isolation & purification , Methods , Methods , VirulenceABSTRACT
We characterized indigenous common bean rhizobia from five districts of the state of Minas Gerais, Brazil. The isolates were trapped by two common bean varieties, the Mineiro Precoce (Andean origin) and Ouro Negro (Mesoamerican origin). Analysis by BOX-PCR of selected isolates detected a high level of genetic diversity.
