CbCTB2, an O-methyltransferase is essential for biosynthesis of the phytotoxin cercosporin and infection of sugar beet by Cercospora beticola

Cornelia Staerkel, Marike J. Boenisch, Cathrin Kröger, Jörg Bormann, Wilhelm Schäfer, Dietmar Stahl

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Background: Cercospora leaf spot disease, caused by the fungus Cercospora beticola, is the most destructive foliar disease of sugar beets (Beta vulgaris) worldwide. Cercosporin, a light-inducible toxin, is essential for necrosis of the leaf tissue and development of the typical leaf spots on sugar beet leaves. Results: In this study we show that the O-methyltransferase gene CTB2 is essential for cercosporin production and pathogenicity in two C. beticola isolates. We established a transformation system for C. beticola protoplasts, disrupted CTB2, and transformed the Δctb2 strains as well as a wild type strain with the DsRed reporter gene. The Δctb2 strains had lost their pigmentation and toxin measurements demonstrated that the Δctb2 strains were defective in cercosporin production. Infection of sugar beets with the wild type and Δctb2 DsRed strains showed that the deletion strain was severely impaired in plant infection. Histological analysis revealed that the CTB2-deficient isolate cannot enter the leaf tissue through stomata like the wild type. Conclusions: Taken together, these observations indicate that cercosporin has a dual function in sugar beet infection: in addition to the well-known role in tissue necrosis, the toxin is required for the early phase of sugar beet infection.

Original languageEnglish (US)
Article number50
JournalBMC plant biology
Volume13
Issue number1
DOIs
StatePublished - Mar 22 2013

Fingerprint Dive into the research topics of 'CbCTB2, an O-methyltransferase is essential for biosynthesis of the phytotoxin cercosporin and infection of sugar beet by Cercospora beticola'. Together they form a unique fingerprint.

Cite this