Xanthomonas citri subsp. citri requires the outer membrane porin OprB for maximal virulence and biofilm formation

GALVAN EM; GOTTIG N; CAROLINA GRANDELLIS; LUNN JE; FICARRA F; IELPI L; OTTADO J

MOLECULAR PLANT PATHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2016

1464-6722

Xanthomonas citri subsp. citri (Xcc) causes canker disease in citrus and biofilm formation is critical for the disease cycle. Outer membrane protein OprB was previously shown to be more abundant in Xcc biofilm compared to the planktonic state. In this work, we showed that loss of OprB in an oprB mutant abolishes bacterial biofilm formation and adherence to the host, and also compromises virulence and efficient epiphytic survival of the bacteria. Moreover, oprB mutant is impaired in bacterial stress resistance. OprB belongs to a family of carbohydrate transport proteins and uptake of glucose was decreased in the mutant strain, indicating that OprB transports glucose. Loss of OprB led to increased production of xanthan exopolysaccharide, and the carbohydrate intermediates of xanthan biosynthesis were are also elevated in the mutant. The xanthan produced by the mutant has a higher viscosity and, unlike wild type xanthan, completely lacks of pyruvylation. Overall, these results suggest that Xcc reprograms its carbon metabolism when it senses a shortage of glucose input. The participation of OprB in the process of biofilm formation and virulence, as well as in metabolic changes to redirect the carbon flux, is discussed. Our results demonstrate the importance of environmental nutrient supply and glucose uptake via OprB for Xcc virulence. This article is protected by copyright. All rights reserved.