title: New Insights into the Roles of Host Gene-Necrotrophic Effector Interactions in Governing Susceptibility of Durum Wheat to Tan Spot and Septoria nodorum Blotch.
abstract: Tan spot and Septoria nodorum blotch (SNB) are important diseases of wheat caused by the necrotrophic fungi Pyrenophora tritici-repentis and Parastagonospora nodorum, respectively. The P. tritici-repentis necrotrophic effector (NE) Ptr ToxB causes tan spot when recognized by the Tsc2 gene. The NE ToxA is produced by both pathogens and has been associated with the development of both tan spot and SNB when recognized by the wheat Tsn1 gene. Most work to study these interactions has been conducted in common wheat, but little has been done in durum wheat. Here, quantitative trait loci (QTL) analysis of a segregating biparental population indicated that the Tsc2-Ptr ToxB interaction plays a prominent role in the development of tan spot in durum. However, analysis of two biparental populations indicated that the Tsn1-ToxA interaction was not associated with the development of tan spot, but was strongly associated with the development of SNB. Pa. nodorum expressed ToxA at high levels in infected Tsn1 plants, whereas ToxA expression in P. tritici-repentis was barely detectable, suggesting that the differences in disease levels associated with the Tsn1-ToxA interaction were due to differences in pathogen expression of ToxA These and previous results together indicate that: (1) the effects of Tsn1-ToxA on tan spot in common wheat can range from nonsignificant to highly significant depending on the host genetic background; (2) Tsn1-ToxA is not a significant factor for tan spot development in durum wheat; and (3) Tsn1-ToxA plays a major role in SNB development in both common and durum wheat. Durum and common wheat breeders alike should strive to remove both Tsc2 and Tsn1 from their materials to achieve disease resistance.
authors: Department of Plant Sciences, North Dakota State University, Fargo, North Dakota 58108.
authors: Simerjot K
authors: SK
authors: Virdi
authors: Department of Plant Pathology, North Dakota State University, Fargo, North Dakota 58108.
authors: Zhaohui
authors: Z
authors: Liu
authors: United States Department of Agriculture-Agricultural Research Service, Cereal Cops Research Unit, Northern Crop Science Laboratory, Fargo, North Dakota 58102.
authors: Megan E
authors: ME
authors: Overlander
authors: United States Department of Agriculture-Agricultural Research Service, Cereal Cops Research Unit, Northern Crop Science Laboratory, Fargo, North Dakota 58102.
authors: Zengcui
authors: Z
authors: Zhang
authors: United States Department of Agriculture-Agricultural Research Service, Cereal Cops Research Unit, Northern Crop Science Laboratory, Fargo, North Dakota 58102.
authors: Steven S
authors: SS
authors: Xu
authors: Department of Plant Pathology, North Dakota State University, Fargo, North Dakota 58108.|United States Department of Agriculture-Agricultural Research Service, Cereal Cops Research Unit, Northern Crop Science Laboratory, Fargo, North Dakota 58102.
authors: Timothy L
authors: TL
authors: Friesen
authors: United States Department of Agriculture-Agricultural Research Service, Cereal Cops Research Unit, Northern Crop Science Laboratory, Fargo, North Dakota 58102 justin.faris@ars.usda.gov.
authors: Justin D
authors: 0000-0002-9653-3287
authors: JD
authors: Faris
mesh_terms: D002874:Chromosome Mapping; D060467:Disease Resistance / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D008040:Genetic Linkage; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D054884:Host-Pathogen Interactions / Q000235:genetics*; D018895:Microsatellite Repeats; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D014908:Triticum / Q000235:genetics* / Q000382:microbiology
chemical_list: D005819:Genetic Markers
keywords: Septoria nodorum; disease resistance; durum wheat; necrotrophic pathogen; tan spot