Response of Resistance Genes H9-H19 in Wheat to Hessian Fly (Dioptera: Cecidomyiidae) Laboratory Biotypes and Field Populations from the Eastern United States

1996 ◽  
Vol 89 (5) ◽  
pp. 1309-1317 ◽  
Author(s):  
Roger H. Ratcliffe ◽  
Herbert W. Ohm ◽  
Fred L. Patterson ◽  
Sue E. Cambron ◽  
Gregory G. Safranski
Keyword(s):  
United States ◽  
Resistance Genes ◽  
Hessian Fly ◽  
Eastern United States

Biotype Status of Hessian Fly (Diptera: Cecidomyiidae) Populations from the Eastern United States and Their Response to 14 Hessian Fly Resistance Genes

1994 ◽  
Vol 87 (4) ◽  
pp. 1113-1121 ◽  
Author(s):  
Roger H. Ratcliffe ◽  
Gregory G. Safranski ◽  
Fred L. Patterson ◽  
Herbert W. Ohm ◽  
Paige L. Taylor
Keyword(s):  
United States ◽  
Resistance Genes ◽  
Hessian Fly ◽  
Eastern United States ◽  
Hessian Fly Resistance

scholarly journals Distribution and Characterization of Podosphaera macularis Virulent on Hop Cultivars Possessing R6-Based Resistance to Powdery Mildew

Plant Disease ◽  
2016 ◽  
Vol 100 (6) ◽  
pp. 1212-1221 ◽  
Author(s):  
Sierra N. Wolfenbarger ◽  
Stephen T. Massie ◽  
Cynthia Ocamb ◽  
Emily B. Eck ◽  
Gary G. Grove ◽  
...  
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Mating Type ◽  
Resistance Genes ◽  
Severe Disease ◽  
The United States ◽  
Fitness Cost ◽  
Eastern United States ◽  
Host Genotype ◽  
Podosphaera Macularis

Host resistance, both quantitative and qualitative, is the preferred long-term approach for disease management in many pathosystems, including powdery mildew of hop (Podosphaera macularis). In 2012, an epidemic of powdery mildew occurred in Washington and Idaho on previously resistant cultivars whose resistance was putatively based on the gene designated R6. In 2013, isolates capable of causing severe disease on cultivars with R6-based resistance were confirmed in Oregon and became widespread during 2014. Surveys of commercial hop yards during 2012 to 2014 documented that powdery mildew is now widespread on cultivars possessing R6 resistance in Washington and Oregon, and the incidence of disease is progressively increasing. Pathogenic fitness, race, and mating type of R6-virulent isolates were compared with isolates of P. macularis lacking R6 virulence. All isolates were positive for the mating type idiomorph MAT1-1 and were able to overcome resistance genes Rb, R3, and R5 but not R1 or R2. In addition, R6-virulent isolates were shown to infect differential cultivars reported to possess the R6 gene and also the R4 gene, although R4 has not yet been broadly deployed in the United States. R6-virulent isolates were not detected from the eastern United States during 2012 to 2015. In growth chamber studies, R6-virulent isolates of P. macularis had a significantly longer latent period and produced fewer lesions on plants with R6 as compared with plants lacking R6, indicating a fitness cost to the fungus. R6-virulent isolates also produced fewer conidia when compared with isolates lacking R6 virulence, independent of whether the isolates were grown on a plant with or without R6. Thus, it is possible that the fitness cost of R6 virulence occurs regardless of host genotype. In field studies, powdery mildew was suppressed by at least 50% on plants possessing R6 as compared with those without R6 when coinoculated with R6-virulent and avirulent isolates. R6 virulence in P. macularis appears to be race specific and, at this time, imposes a measurable fitness penalty on the fungus. Resistance genes R1 and R2 appear to remain effective against R6-virulent isolates of P. macularis in the U.S. Pacific Northwest.

Virulence in Hessian Fly (Diptera: Cecidomyiidae) Field Collections From the Southeastern United States to 21 Resistance Genes in Wheat

2010 ◽  
Vol 103 (6) ◽  
pp. 2229-2235 ◽  
Author(s):  
Sue E. Cambron ◽  
G. David Buntin ◽  
Randy Weisz ◽  
Jeffery D. Holland ◽  
Kathy L. Flanders ◽  
...  
Keyword(s):  
United States ◽  
Resistance Genes ◽  
Southeastern United States ◽  
Hessian Fly

scholarly journals Virulence of Blumeria graminis f. sp. tritici on Winter Wheat in the Eastern United States

Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 64-68 ◽  
Author(s):  
A. S. Niewoehner ◽  
S. Leath
Keyword(s):  
United States ◽  
Winter Wheat ◽  
Resistance Genes ◽  
Virulence Genes ◽  
Southeastern United States ◽  
Blumeria Graminis ◽  
Eastern United States ◽  
Single Spore ◽  
Differential Host ◽  
Wheat Leaves

Samples of perithecia of Blumeria graminis f. sp. tritici from senescing wheat leaves were collected by cooperators from 17 states. Ascospores were discharged from perithecia and single-spore isolates were characterized for virulence genes using a differential host series containing 15 known resistance genes. A total of 520 isolates from 17 states were characterized in 1993 and 1994. Virulence frequencies and complexity and racial composition were examined. The data were analyzed for associations among sets of virulence genes and the geographical distribution of phenotypes. Virulence to Pm3c, Pm3f, pm5, Pm6, and Pm7 was present in all states surveyed. Since 1990, virulence to Pm3a has increased in the northeast, and virulence to Pm1, Pm4b, Pm8, and Pm17 has increased across the area surveyed. The resistance genes Pm12 and Pm16 remain highly effective in the southeastern United States. An increase in virulence frequencies and complexity of isolates was observed.

Biotype Composition of Hessian Fly (Diptera: Cecidomyiidae) Populations from the Southeastern, Midwestern, and Northwestern United States and Virulence to Resistance Genes in Wheat

2000 ◽  
Vol 93 (4) ◽  
pp. 1319-1328 ◽  
Author(s):  
Roger H. Ratcliffe ◽  
Sue E. Cambron ◽  
Kathy L. Flanders ◽  
Nilsa A. Bosque-Perez ◽  
Stephen L. Clement ◽  
...  
Keyword(s):  
United States ◽  
Resistance Genes ◽  
Hessian Fly

scholarly journals Presence of Plasmid-Mediated Quinolone Resistance in Klebsiella pneumoniae Isolates Possessing blaKPC in the United States

2008 ◽  
Vol 52 (7) ◽  
pp. 2680-2682 ◽  
Author(s):  
Andrea Endimiani ◽  
Lenore L. Carias ◽  
Andrea M. Hujer ◽  
Christopher R. Bethel ◽  
Kristine M. Hujer ◽  
...  
Keyword(s):  
United States ◽  
Klebsiella Pneumoniae ◽  
Resistance Genes ◽  
The United States ◽  
Quinolone Resistance ◽  
Conjugative Plasmid ◽  
Eastern United States

ABSTRACT The presence of plasmid-mediated quinolone resistance genes [i.e., qnrA, qnrB, qnrS, aac(6′)-Ib-cr, and qepA] was evaluated among 42 bla KPC-containing Klebsiella pneumoniae isolates collected in the eastern United States. One isolate carried the bla KPC-3 and qnrB19 genes on the same conjugative plasmid, whereas another carried the bla KPC-3 and qnrA1 genes on separate plasmids.

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