Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: Evaluation, Enhancement, Genetics and Breeding of Lettuce, Spinach, and Melon Title: Gaps and perspectives of pathotype and race determination in golovinomyces cichoracearum and podosphaera xanthii.

Authors
item Lebeda, Ales -
item Kristkova, Eva -
item Coffey, Micheal -
item McCreight, James

Submitted to: Mycoscience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 26, 2010
Publication Date: May 1, 2011
Citation: Lebeda, A., Kristkova, E., Coffey, M., Mccreight, J.D. 2011. Gaps and perspectives of pathotype and race determination in golovinomyces cichoracearum and podosphaera xanthii. Mycoscience. 52:159-164.

Interpretive Summary: Cucurbit powdery mildew is a serious disease of field and greenhouse cucurbits (cucumber, melon, watermelon, squash, gourd). The disease reduces fruit yield and quality. Two fungi, Golovinomyces cichoracearum and Podosphaera xanthii, are considered the most important species causing disease. Both species are genetically variable in their ability to infect cucurbits as indicated by the existence of large number of different pathotypes and races. Various, independent systems of cucurbit powdery mildew pathotype and race determinations and denominations are worldwide-used, and there is no international cooperation or agreement in those topics. Identification of cucurbit powdery mildew pathotypes is based on intergeneric and interspecific differences in host–cucurbit powdery mildew interactions. The currently used set cucurbit powdery mildew pathotype differentials include one each of the six agriculturally most important cucurbit genera and species. Cucurbit powdery mildew races are characterized by the specialization to different cultivars or lines of one host species. Races have, to date, been differentiated only on melon (Cucumis melo). The most frequently used set of melon differentials includes 11 genotypes that can differentiate CPM races originating from melon and other cucurbits, e.g., cucumber, Cucurbita spp. and watermelon. In this paper, we critically review the current state, gaps and perspectives of understanding of variation for pathogenicity of these two CPM pathogens at the pathotype and race levels.

Technical Abstract: Golovinomyces cichoracearum and Podosphaera xanthii (family Erysiphaceae) are the most important species causing cucurbit powdery mildew (CPM), a serious disease of field and greenhouse cucurbits. Both species are highly variable in their pathogenicity and virulence, as indicated by the existence of large number of different pathotypes and races. Various independent systems of CPM pathotype and race determinations and denominations are used worldwide. CPM pathotype identification is based on intergeneric and interspecific differences in host-CPM interactions. The most commonly used set of CPM pathotype differentials includes one genotype from four species representing three agriculturally important cucurbit genera plus two genotypes from a fifth species, melon Cucumis melo L. CPM races are characterized by specialization on different cultivars or lines of one host species and have, to date, been differentiated only on melon (C. melo L.). The most frequently used set of melon differentials includes 11 genotypes that can differentiate CPM races originating from melon and other cucurbits, e.g., cucumber, Cucurbita spp., and watermelon. In this paper, we critically review the current state, gaps, and perspectives in our understanding of pathogenicity variation in these two CPM pathogens at the pathotype and race levels.

Last Modified: 11/22/2014