Submitted to: European Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2003
Publication Date: 3/1/2004
Citation: Jimenez-Hidalgo, I., Virgen, G., Martinez, D., Vandemark, G.J., Alejo, J., Olalde, V. 2004. Identification and characterization of soft rot bacteria of agave tequilana weber var.azul. European Journal of Plant Pathology. 110:317-331. Interpretive Summary: The alcoholic beverage tequila is produced by the fermentation of the center of the blue agave plant, Agave tequilana var. Azul. The federal government of Mexico has tried to maintain control of the quality of tequila by instituting various laws. These laws permit that only blue agave can be used for the production of tequila, and also that the blue agave may only be grown in specific areas of Mexico. The blue agave is a relatively long-lived plant, and cannot be harvested for the production of tequila until the plant is between 7-10 years of age. Currently in Mexico, a disease epidemic is affecting blue agave, and the disease is having a profound effect on the availability of blue agave for the production of tequila. The pathogenic agents responsible for this disease, which is characterized by soft rot of leaves, had not been identified. We isolated bacteria from several infected blue agave plants, and using these bacteria to inoculate the leaves of blue agave plants in the greenhouse, were able to reproduce the disease symptoms typically seen in the field. We then used a combination of biochemical tests and DNA fingerprint technologies to determine the identity of the bacterial isolates causing the soft rot disease. Now that we know the identity of the disease-causing bacteria we can develop tests for the rapid detection of the bacteria in infected plants, and can also begin to identify plants of blue agave that are resistant to the bacterial disease.
Technical Abstract: Agave tequilana is the source of primary material for the production of the alcoholic beverage tequila. A bacterial disease has affected the Agave tequilana crop in recent years. Previous reports indicated that Erwinia carotovora is the main pathogen, but we identified four other bacterial isolates that were able to produce soft-rot symptoms based on greenhouse pathogenicity assays. An extensive characterization (antibiotic sensitivity, immunological test, fatty acids profile and biochemical properties) was made of each isolate. Cluster analysis of two phenotypic characteristics (fatty acids and biochemical profiles) grouped together two of the four isolates. These two isolates are closely related to Enterobacter agglomerans. The other two isolates were distinct from the two isolates that were similar to Enterobacter agglomerans. Three different species were identified among the four tested isolates based on biochemical and fatty acids results, Enterobacter agglomerans, Pseudomonas mendocina and Serratia sp.