Rapid and sensitive detection of Citrus Bacterial Canker by loop-mediated isothermal amplification combined with simple visual evaluation methods

Background  

Citrus Bacterial Canker (CBC) is a major, highly contagious disease of citrus plants present in many countries in Asia, Africa and America, but not in the Mediterranean area. There are three types of Citrus Bacterial Canker, named A, B, and C that have different genotypes and posses variation in host range within citrus species. The causative agent for type A CBC is Xanthomonas citri subsp. citri, while Xanthomonas fuscans subsp. aurantifolii, strain B causes type B CBC and Xanthomonas fuscans subsp. aurantifolii strain C causes CBC type C. The early and accurate identification of those bacteria is essential for the protection of the citrus industry. Detection methods based on bacterial isolation, antibodies or polymerase chain reaction (PCR) have been developed previously; however, these approaches may be time consuming, laborious and, in the case of PCR, it requires expensive laboratory equipment. Loop-mediated isothermal amplification (LAMP), which is a novel isothermal DNA amplification technique, is sensitive, specific, fast and requires no specialized laboratory equipment.     

Yeast diversity in a mesotrophic lake on the karstic plateau of Lagoa Santa,MG-Brazil

The yeast diversity in a paleo-karstic lake of the Lagoa Santa plateau was studied during March 1986–March 1987. Water samples were collected monthly at five stations and the yeasts were isolated at 25 °C on Sabourad dextrose agar supplemented with 0.5% of yeast extract and 10 mg% of chloramphenicol. August and February showed the highest numbers of isolates, coinciding, respectively with the beginning and the ending of stratification. Of 56 isolated species, Aureobasidium pullulans, Candida famata, Cryptococcus albidus, Cryptococcus laurentii, Rhodotorula glutinis, Rhodotorula rubra and Trichosporon cutaneum occurred at the highest frequencies. A. pullulans showed greatest prevalence during the dry period (winter), whereas C. famata, Cr. albidus, Cr. laurentii and Rh. rubra were prevalent during the rainy season (summer). Tr. cutaneum was distributed between July and November. Most isolates yeasts are associated with plants and soils, and are important in decomposition of aquatic macrophytes. Furthermore, a possible role of these species as indicators of pollution is discussed.