Métodos para la detección de a la detección de Xanthomonas Xanthomonas campestris pv. vesicatoria en semilla de toma en semilla de tomate (Lycopersicon esculentum Mill)

Abstract

The culture of tomato occupies the second place in Méxicol according to the surface seeded and first per the production value. This culture is affected by several patho genic agents among which Xanthomonas campestris pv. Vesicatoria,, is considered the most dangerous. When importing tomato seed, chances are that some pathogenic stocks are intro duced to the country, since this microorganism is transmitted by this route. 

The aim of this work was to determine the best method for the detection of bacterium X. c. pv. vesicatoria in tomato seed. This research was made in laboratories and greenhouses of the Universidad Autónoma Agraria Antonio Narro, where seeds of com mercial lots of the varieties Hayslip, Homestead 61, Rio Grande and Winner were ana lyzed. 12 grams of seed of each variety were placed in a phosphate buffer 0,05 M, to 4ºC, during all night, and later serial dilutions of the filtrate of the seed and the buffer were made. 0,1 mililiter was seeded, of each dilution (mother solution, 10 -1, 10 -2 and 10 -3) for the recovery of the bacteria in the methods Tween B, CKTM and TBCK, under a bifactorial adjustment three by four, in a completely at random design with three replications. There were no differences between methods as far as detection of the bacteria in UFC/g was concerned, but they were found between varieties, of which the most contaminated by this bacteria were the Hayslip and the Rio Grande. As far as time of appearance of the UFC is concerned in each of the methods, the best one was the Tween B, that registered an average in the appearance of the UFC of 84 hours. With respect to the germination capac ity, there were no differences between varieties. The identification of the stocks was made by means of biochemical tests, semiselective sowing in differential environments, and tests of pathogenicity ; the symptoms appeared of 12 to 14 days after the inoculations in the fruits, and the isolation of the bacteria corresponded again to the one isolated initially.