Open AccessIdentification of a Tomatinase in the Tomato-Pathogenic Actinomycete Clavibacter michiganensis subsp. michiganensis NCPPB382
Author(s) -
Olaf Kaup,
Ines Gräfen,
Eva-Maria Zellermann,
Rudolf Eichenlaub,
Karl-Heinz Gartemann
Publication year - 2005
Publication title -
molecular plant-microbe interactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.565
H-Index - 153
eISSN - 1943-7706
pISSN - 0894-0282
DOI - 10.1094/mpmi-18-1090
Subject(s) - clavibacter michiganensis , mutant , biology , transposable element , microbiology and biotechnology , transposon mutagenesis , gene , biochemistry , pathogen
The insertion site of a transposon mutant of Clavibacter michiganensis subsp. michiganensis NCPPB382 was cloned and found to be located in the gene tomA encoding a member of the glycosyl hydrolase family 10. The intact gene was obtained from a cosmid library of C. michiganensis subsp. michiganensis. The deduced protein TomA (543 amino acids, 58 kDa) contains a predicted signal peptide and two domains, the N-terminal catalytic domain and a C-terminal fibronectin III-like domain. The closest well-characterized relatives of TomA were tomatinases from fungi involved in the detoxification of the tomato saponin α-tomatine which acts as a growth inhibitor. Growth inhibition of C. michiganensis subsp. michiganensis by α-tomatine was stronger in the tomA mutants than in the wild type. Tomatinase activity assayed by deglycosylation of α-tomatine to tomatidine was demonstrated in concentrated culture supernatants of C. michiganensis subsp. michiganensis. No activity was found with the tomA mutants. However, neither the transposon mutant nor a second mutant constructed by gene disruption was affected in virulence on the tomato cv. Moneymaker.