Cercospora beticola: The intoxicating lifestyle of the leaf spot pathogen of sugar beet

Authors: Rangel, Lorena; SPANNER, REBECCA - North Dakota State University; EBERT, MALAIKA - North Dakota State University; PETHYBRIDGE, SARAH - Cornell University; STUKENBROCK, EVA - Max Planck Institute For Evolutionary Biology; DE JONGE, RONNIE - Utrecht University; SECOR, GARY - North Dakota State University; Bolton, Melvin

Submitted to: Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/17/2020
Publication Date: 7/17/2020
Citation: Rangel, L., Spanner, R.E., Ebert, M., Pethybridge, S.J., Stukenbrock, E.H., De Jonge, R., Secor, G.A., Bolton, M.D. 2020. Cercospora beticola: The intoxicating lifestyle of the leaf spot pathogen of sugar beet. Molecular Plant Pathology. 21:1020-1041. https://doi.org/10.1111/mpp.12962.
DOI: https://doi.org/10.1111/mpp.12962

Interpretive Summary: Cercospora leaf spot, caused by the fungal pathogen Cercospora beticola, is the most destructive foliar disease of sugar beet worldwide. This paper summarizes our current understanding of the molecular interactions that occur between C. beticola and its sugar beet host. We highlight mechanisms that this fungus utilizes to cause disease and overcome currently used disease management strategies. Finally, we discuss future prospects for studying and managing C. beticola infections in the context of newly employed molecular tools to uncover additional information regarding the biology of this pathogen.

Technical Abstract: SUMMARY Cercospora leaf spot, caused by the fungal pathogen Cercospora beticola, is the most destructive foliar disease of sugar beet worldwide. This review discusses C. beticola genetics, genomics and biology and summarizes our current understanding of the molecular interactions that occur between C. beticola and its sugar beet host. We highlight the known virulence arsenal of C. beticola as well as its ability to overcome currently used disease management strategies. Finally, we discuss future prospects for studying and managing C. beticola infections in the context of newly employed molecular tools to uncover additional information regarding the biology of this pathogen. Taxonomy: Cercospora beticola Sacc.; Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes, Order Capnodiales, Family Mycosphaerellaceae, Genus Cercospora. Host range: Well-known pathogen of sugar beet (Beta vulgaris) and most species of the Beta genus. Reported as pathogenic on other members of the Chenopodiaceae (spinach, lamb’s quarters) as well as members of the Acanthaceae (bear’s breeches), Asteraceae (safflower, lettuce), Brassicaceae (wild mustard) and Polygonaceae (broad-leaved dock) families. Disease symptoms: Leaves infected with C. beticola exhibit circular lesions that are colored tan to grey in the center and are often delimited by reddish-purple rings. As disease progresses, spots can coalesce to form larger necrotic areas causing severely infected leaves to wither and die. At the center of these spots are black spore-bearing structures (pseudostromata). Older leaves often show symptoms first and younger leaves become infected as the disease progresses. Management: Mixing fungicides with different modes-of-action is currently performed although elevated resistance has been documented in most employed fungicide classes. Breeding for high-yielding cultivars with improved host resistance is an ongoing effort and prudent cultural practices, such as crop rotation, weed host management and cultivation to reduce infested residue levels, are widely used to manage disease.