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ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Publications at this Location » Publication #383848
Research Project: Biology, Ecology, and Genomics of Pathogenic and Beneficial Microorganisms of Wheat, Barley, and Biofuel Brassicas

Location: Wheat Health, Genetics, and Quality Research

Title: Occurrence of eyespot of cereals in Tunisia and identification of Oculimacula species and mating types

Author
item GARGOURI, S - University Of Carthage, Tunisia
item BOUATROUS, A - University Of Carthage, Tunisia
item MURRAY, T - Washington State University
item Paulitz, Timothy
item KHEMIR, E - University Of Carthage, Tunisia
item SOUISSI, A - University Of Carthage, Tunisia
item CHEKALI, S - University Of Carthage, Tunisia
item BURGESS, L - University Of Sydney

Submitted to: Canadian Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/12/2021
Publication Date: 5/4/2022
Citation: Gargouri, S., Bouatrous, A., Murray, T.D., Paulitz, T.C., Khemir, E., Souissi, A., Chekali, S., Burgess, L.W. 2022. Occurrence of eyespot of cereals in Tunisia and identification of Oculimacula species and mating types. Canadian Journal of Plant Pathology. 44(3):345-353. https://doi.org/10.1080/07060661.2021.1995501.
DOI: https://doi.org/10.1080/07060661.2021.1995501

Interpretive Summary: A survey was conducted in Tunisia for eyespot (Oculimacula), on spring cereals. This is a disease of cereal stems and causes lodging. This survey was conducted in 4 climatic zones from 2010-2014. Disease was higher in wetter areas, and less on barley. Both mating types were detected using molecular techniques, which suggests that sexual reproduction may be occurring.

Technical Abstract: The aims of this study were to investigate the occurrence of eyespot in commercial spring cereal crops of in four climatic areas in Tunisia and characterize the dominant species of Oculimacula responsible for the disease. A total of 294 of wheat, barely and oat crops fields were surveyed for eyespot incidence and severity during four cropping seasons from 2010 to 2014. Eyespot was identified in 63.5% of the crops with an average incidence of 23.1% infected stems. The number of crops as well as incidence and severity of disease increased significantly across the five 5 years of the study. A significant difference in the occurrence of eyespot among the climatic regions was noted with the wetter areas having greater disease incidence. The highest incidence of eyespot was recorded in durum wheat and bread wheat fields, whereas barley was significantly less infested. The effect of previous crop on the incidence of eyespot was not significant; however, the mean incidence and severity were greater when a cereal was a previous crop. All 70 isolates collected in this study were identified as O. yallundae using species specific primers. In multiplex PCR, 39 were identified as MAT1-2 and 31 as MAT1-1. This study highlights the influence of climatic conditions on the distribution of eyespot in the cereal growing areas of Tunisia as well as the increasing occurrence of the disease. The predominance of O. yallundae is an important consideration in the choice of integrated management strategies for eyespot. The presence of both mating types of O. yallundae suggests that sexual reproduction may be occurring.