UN NUEVO FACTOR TRANSCRIPCIONAL IMPLICADO EN LA QUIMIOTAXIS, FORMACION DE BIOFILM Y VIRULENCIA DE Xanthomonas citri subsp. citri

PABLO YARYURA; VALERIA CONFORTE; FLORENCIA MALAMUD; ROXANA ROESCHLIN; VERÓNICA DE PINO; ATILIO CASTAGNARO; J. MAXWELL DOW; MARÍA ROSA MARANO; ADRIÁN VOJNOV

Mar del Plata

Encuentro; VIII Encuentro Latinoamericano y del Caribe de Biotecnología - REDBIO ARGENTINA 2013; 2013

Rebio Argentina Asociación Civil

Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is one of the mayor diseases producing great economic losses worldwide. Xcc ability to form biofilm structures on leaves is closely related to its virulence. Through a screening of mutants generated by the Tn5 transposon insertion in order to find those defective in biofilm formation, we found the ntrC mutant. This gene encodes a transcription factor that had not been described previously in Xcc. Here we demonstrated that the ntrC mutant is unable to form the wild type mature biofim structures. Its capacity to move toward grapefruit leaves extracts is severely reduced due to the absence of flagella as a consequence of the down-regulation of flagellar genes. Moreover, this ntrC mutant is less virulent than the wild type strain. Introduction of gene encoding an enzyme that can degrade cyclic 3´,5´-diguanylate (c-di-GMP) into the ntrC mutant restored chemotaxis, motility and virulence to wild type levels. This remark suggests a possible relationship between NtrC and c-di-GMP in bacteria.