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Fargo, ND, United States

Liu Z.,North Dakota State University | El-Basyoni I.,University of Nebraska - Lincoln | Kariyawasam G.,North Dakota State University | Zhang G.,Kansas State University | And 7 more authors.
Plant Disease | Year: 2015

Tan spot and Stagonospora nodorum blotch (SNB), often occurring together, are two economically significant diseases of wheat in the Northern Great Plains of the United States. They are caused by the fungi Pyrenophora tritici-repentis and Parastagonospora nodorum, respectively, both of which produce multiple necrotrophic effectors (NE) to cause disease. In this work, 120 hard red winter wheat (HRWW) cultivars or elite lines, mostly from the United States, were evaluated in the greenhouse for their reactions to the two diseases as well as NE produced by the two pathogens. One P. nodorum isolate (Sn4) and four Pyrenophora tritici-repentis isolates (Pti2, 331-9, DW5, and AR CrossB10) were used separately in the disease evaluations. NE sensitivity evaluation included ToxA, Ptr ToxB, SnTox1, and SnTox3. The numbers of lines that wer rated highly resistant to individual isolates ranged from 11 (9%) to 30 (25%) but only six lines (5%) were highly resistant to all isolates, indicating limited sources of resistance to both diseases in the U.S. adapted HRWW germplasm. Sensitivity to ToxA was identified in 83 (69%) of the lines and significantly correlated with disease caused by Sn4 and Pti2, whereas sensitivity to other NE was present at much lower frequency and had no significant association with disease. As expected, association mapping located ToxA and SnTox3 sensitivity to chromosome arm 5BL and 5BS, respectively. A total of 24 potential quantitative trait loci was identified with −log (P value) > 3.0 on 12 chromosomes, some of which are novel. This work provides valuable information and tools for HRWW production and breeding in the Northern Great Plains. © 2015 The American Phytopathological Society. Source

Anderson J.V.,Biosciences Research Laboratory | Tedrow T.,Biosciences Research Laboratory | Tedrow T.,Kansas State University | Hulke B.,U.S. Department of Agriculture | Kennedy A.C.,Washington State University
Journal of Agricultural and Food Chemistry | Year: 2010

Incubation of dormant wild oat (Avena fatua L., isoline M73) caryopses for 1-3 days with Fusarium avenaceum seed-decay isolate F.a.1 induced activity of the plant defense enzyme polyphenol oxidase (PPO). Both extracts and leachates obtained from F.a.1-treated caryopses had decreased abundance of an ̃57 kDa antigenic PPO and increased abundance of antigenic PPOs ranging from ̃52 to 14 kDa, as compared to extracts and leachates from untreated caryopsis. Leachates from caryopsis incubated for 2 days with F.a.1 also had 5.1- and 7.5-fold more total PPO activity/g fwt and specific activity, respectively. Fractionation of leachate proteins by ion-exchange chromatography associated the majority of PPO activity with an ̃36 kDa protein from untreated caryopses and ̃36, 25, and 24 kDa proteins from F.a.1-treated caryopses. Predicted peptide sequences obtained from high-performance liquid chromatography-tandem mass spectrometry analyses indicated that the ̃57 and 36 kDa wild oat proteins had a strong similarity to wheat PPO. However, the 25 and 24 kDa proteins were most similar to a Chitinase and oxalate oxidase, respectively. Our results indicate that F.a.1-induced activation of latent PPO in wild oat caryopsis likely involves a cleavage mechanism allowing activated PPOs to be readily mobilized into their surrounding environment. © 2010 American Chemical Society. Source

Gallagher R.S.,Pennsylvania State University | Ananth R.,Pennsylvania State University | Granger K.,Pennsylvania State University | Bradley B.,Pennsylvania State University | And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2010

The objective of this research was to identify and quantify the phenolic and short-chained aliphatic organic acids present in the seeds of three wild-type populations of wild oat and compare these results to the chemical composition of seeds from two commonly utilized wild oat isolines (M73 and SH430). Phenolic acids have been shown to serve as germination inhibitors, as well as protection for seeds from biotic and abiotic stress factors in other species, whereas aliphatic organic acids have been linked to germination traits and protection against pathogens. Wild oat populations were grown under a "common garden" environment to remove maternal variation, and the resulting seeds were extracted to remove the readily soluble and chemically bound phenolic and aliphatic organic acid components. Compounds were identified and quantified using gas chromatography-mass spectrometry. Ferulic and p-coumaric acid comprised 99% of the total phenolic acids present in the seeds, of which 91% were contained in the hulls and 98% were in the chemically bound forms. Smaller quantities of OH benzoic and vanillic acid were also detected. Soluble organic acids concentrations were higher in the M73 isoline compared to SH430, suggesting that these chemical constituents could be related to seed dormancy. Malic, succinic, fumaric and azelaic acid were the dominant aliphatic organic acids detected in all seed and chemical fractions. © 2009 American Chemical Society. Source

Chao W.S.,Biosciences Research Laboratory | Dogramaci M.,Biosciences Research Laboratory | Foley M.E.,Biosciences Research Laboratory | Horvath D.P.,Biosciences Research Laboratory | Anderson J.V.,Biosciences Research Laboratory
PLoS ONE | Year: 2012

Quantitative real-time polymerase chain reaction (qRT-PCR) is the most important tool in measuring levels of gene expression due to its accuracy, specificity, and sensitivity. However, the accuracy of qRT-PCR analysis strongly depends on transcript normalization using stably expressed reference genes. The aim of this study was to find internal reference genes for qRT-PCR analysis in various experimental conditions for seed, adventitious underground bud, and other organs of leafy spurge. Eleven candidate reference genes (BAM4, PU1, TRP-like, FRO1, ORE9, BAM1, SEU, ARF2, KAPP, ZTL, and MPK4) were selected from among 171 genes based on expression stabilities during seed germination and bud growth. The other ten candidate reference genes were selected from three different sources: (1) 3 stably expressed leafy spurge genes (60S, bZIP21, and MD-100) identified from the analyses of leafy spurge microarray data; (2) 3 orthologs of Arabidopsis "general purpose" traditional reference genes (GAPDH_1, GAPDH_2, and UBC); and (3) 4 orthologs of Arabidopsis stably expressed genes (UBC9, SAND, PTB, and F-box) identified from Affymetrix ATH1 whole-genome GeneChip studies. The expression stabilities of these 21 genes were ranked based on the CT values of 72 samples using four different computation programs including geNorm, Normfinder, BestKeeper, and the comparative ΔCT method. Our analyses revealed SAND, PTB, ORE9, and ARF2 to be the most appropriate reference genes for accurate normalization of gene expression data. Since SAND and PTB were obtained from 4 orthologs of Arabidopsis, while ORE9 and ARF2 were selected from 171 leafy spurge genes, it was more efficient to identify good reference genes from the orthologs of other plant species that were known to be stably expressed than that of randomly testing endogenous genes. Nevertheless, the two newly identified leafy spurge genes, ORE9 and ARF2, can serve as orthologous candidates in the search for reference genes from other plant species. Source

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