ARS | Publication request: Development of Simple Sequence Repeat Markers from Expressed Sequence Tags of the Maize Gray Leaf Spot Pathogen, Cercospora Zea-Maydis

Submitted to: Molecular Ecology Resources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 17, 2009
Publication Date: July 17, 2009
Citation: Dunkle, L.D., Crane, C.F., Goodwin, S.B. 2009. Development of Simple Sequence Repeat Markers from Expressed Sequence Tags of the Maize Gray Leaf Spot Pathogen, Cercospora Zea-Maydis. Molecular Ecology Resources. 9:1375-1379.

Interpretive Summary: Gray leaf spot, caused by the fungus Cercospora zeae-maydis, is one of the most destructive foliar diseases of corn throughout the world. The pathogen reproduces by asexual spores (conidia), and no sexual stage has been reported. However, two mating types are known to occur, suggesting the possibility that this species also undergoes sexual reproduction. The objective of this study was to develop simple sequence repeat (SSR) markers for studies of population structure and to assess the occurrence of sexual recombination in C. zeae-maydis. We discovered 10 SSR markers that revealed substantial gene diversity in a local population of the pathogen. These 10 SSR loci should be very useful to plant pathologists and geneticists in future analyses of the genetic structure of C. zeae-maydis populations to reveal whether the genetic diversity results from sexual reproduction and to assess the probability of changes in the ability of this fungus to cause gray leaf spot.

Technical Abstract: Ten simple sequence repeat markers were developed from expressed sequence tags of Cercospora zeae-maydis, the cause of gray leaf spot of maize (Zea mays). All loci were evaluated on 80 isolates from a local population of C. zeae-maydis and all were highly polymorphic, with 4 to 14 alleles per locus. Nei’s gene diversity (h) ranged from 0.610 to 0.907 per locus. These values were very high, from 76 to 98% of the theoretical maximum. Screens of the primer pairs with related Dothideomycete species indicated that they are specific to C. zeae-maydis.