ABSTRACT
ABSTRACT The interaction between plants and pathogens is a very dynamic and complex relationship that also includes a high degree of specificity, and it is precisely this last characteristic which triggers such important responses in the survival of one or the other. The pathosystem formed by tomato (Solanum lycopersicum L.) and Fusarium oxysporum f. sp. lycopersici (Fol) has been the subject of multiple studies due to the importance of the vegetable worldwide and for the economic and ecological impact of the fungus responsible for the vascular wilt disease in tomato, causing losses that go up to 100%. One way to find alternatives for the management of any pathosystem is to know the actors involved and the mechanisms that govern the interaction through technological and scientific advances that clearly show how the interaction develops on a genetic level. This review collects the information from different scientific sources with focus on the knowledge of the fungus, tomato cultivation and plant defense applied to this pathosystem, as well as the molecular mechanisms.
RESUMEN La interacción entre plantas y patógenos es una relación muy dinámica y compleja, que conlleva un alto grado de especificidad y es esta última característica, la que desencadena respuestas tan importantes en la supervivencia de uno u otro. El patosistema formado por tomate (Solanum lycopersicum L.) y Fusarium oxysporum f. sp. lycopersici (Fol) ha sido objeto de múltiples estudios, debido a la importancia de la hortaliza, a nivel mundial y por el impacto económico y ecológico del hongo, responsable de la marchitez vascular, provocando pérdidas que llegan hasta el 100%. Una forma de encontrar alternativas para el manejo de cualquier patosistema es conocer los actores involucrados y los mecanismos que rigen la interacción, a través de avances tecnológicos y científicos, que muestren, claramente, cómo se desarrolla la interacción, a nivel genético. Esta revisión recoge la información de fuentes científicas con énfasis en el conocimiento del hongo, el cultivo del tomate y la defensa vegetal, aplicada a este patosistema, así como los mecanismos moleculares.
ABSTRACT
Rice blast disease, caused by Magnaporthe oryzae, is one of the most importance diseases of rice production worldwide. The key role of defense mechanism to combat this fungus in rice follows the gene-for-gene concept, which a plant resistant (R) gene product recognizes a fungal avirulent (AVR) effector and triggers the hypersensitive response. However, the AVR genes have been shown to be rapidly evolving resulting in high level of genetic diversity. The aims of this study were to examine the nucleotide sequence variation of AVR-Pita1 gene in Thai rice blast isolates and to identify the severity of blast disease using isogenic line of Pita gene. Seventy-six rice blast isolates collected from different parts of Thailand were used. Gene specific primers for AVR-Pita1 gene coding sequence were designed and used for identifying the genetic diversity of AVR-Pita1 gene by PCR amplification and sequencing. The obtained sequences were analysed for genetic variation and genetic relationship. Our results revealed the association between the sequence variations of AVR-Pita1 and selective forces from Pita gene. This phenomenon demonstrated the coevolution between rice blast resistant gene in rice and avirulent gene in blast fungus. The information about variation and evolutionary mechanisms of AVR gene obtained from this study can be used in rice blast resistant breeding programme
ABSTRACT
It was widely believed that the interaction between rice and rice blast fungus can be interpreted by the gene-for-gene hypothesis. Two interaction models between rice blast fungus and anti-disease genes had been briefed. They were receptor-ligand model and guard model. The progress of research about molecular marker and position on avirulence genes of the pathogens of rice blast (Magnaporthe oryzae) was reviewed, and the methods to clone and the cloned avirulence genes of rice blast fungus were also summarized.