Open AccessRole of the FnIII domain associated with a cell wall‐degrading enzyme cellobiosidase of Xanthomonas oryzae pv. oryzae
Author(s) -
Nathawat Rajkanwar,
Maku Roshan V.,
Patel Hitendra K.,
Sankaranarayanan Rajan,
Sonti Ramesh V.
Publication year - 2022
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.13205
Subject(s) - xanthomonas oryzae , virulence , xanthomonas , xanthomonas oryzae pv. oryzae , virulence factor , secretion , biology , microbiology and biotechnology , biochemistry , gene
Cellobiosidase (CbsA) is an important secreted virulence factor of Xanthomonas oryzae pv. oryzae (Xoo), which causes bacterial blight of rice. CbsA is one of several cell wall‐degrading enzymes secreted by Xoo via the type II secretion system (T2SS). CbsA is considered a fundamental virulence factor for vascular pathogenesis. CbsA has an N‐terminal glycosyl hydrolase domain and a C‐terminal fibronectin type III (FnIII) domain. Interestingly, the secreted form of CbsA lacks the FnIII domain during in planta growth. Here we show that the presence of the FnIII domain inhibits the enzyme activity of CbsA on polysaccharide substrates like carboxymethylcellulose. The FnIII domain is required for the interaction of CbsA with SecB chaperone, and this interaction is crucial for the stability and efficient transport of CbsA across the inner membrane. Deletion of the FnIII domain reduced virulence similar to Δ cbsA Xoo, which corroborates the importance of the FnIII domain in CbsA. Our work elucidates a hitherto unknown function of the FnIII domain in enabling the virulence‐promoting activity of CbsA.