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2012 APS Annual Meeting Abstracts of Presentations 2012 APS Annual Meeting Abstracts of Presentations Abstracts submitted for presentation at the APS Annual Meeting in Providence, Rhode Island, August 4–8, 2012 (including abstracts submitted for presentation at the 2012 APS Northeastern Division Meeting). The abstracts are arranged alphabetically by the first author’s name. Recommended format for citing annual meet- ing abstracts, using the first abstract below as an example, is as follows: Abbas, H. D., Shier, W., Weaver, M. A., and Horn, B. W. 2012. Detection of afla- toxigenic Aspergillus flavus contamination of coconut (Cocos nucifera) nutmeat (copra) using ammonia treatment. (Abstr.) Phytopathology 102(Suppl. 4):S4.1. http://dx.doi.org/10.1094/PHYTO-102-7-S4.1 Detection of aflatoxigenic Aspergillus flavus contamination of coconut rotation for SDS management is not well understood. In this study, the effect (Cocos nucifera) nutmeat (copra) using ammonia treatment of long-term crop rotations in reducing SDS was studied in 2010 and 2011, in H. D. ABBAS (1), W. Shier (2), M. A. Weaver (1), B. W. Horn (3) a field trial established in Iowa since 2002. The trial included three rotation (1) USDA-ARS BCPRU, Stoneville, MS, U.S.A.; (2) University of treatments: corn-soybean, corn-soybean-oat/red-clover, and corn-soybean- Minnesota, Minneapolis, MN, U.S.A.; (3) USDA-ARS, National Peanut oat/alfalfa-alfalfa. SDS incidence and severity, root rot and root growth, yield, Research Laboratory, Dawson, GA, U.S.A. and F. virguliforme and soybean cyst nematode (SCN) populations in soil Phytopathology 102:S4.1 were assessed. In both years, the 2-year rotation showed greater (P<0.001) SDS incidence and severity, and lower yield, compared to the 3- and 4-year For many crops government regulations define mycotoxin contamination rotations. Roots from the 2-year rotation showed more severe rot and reduced levels that represent the primary determinants of quality, value and possible uses of crops. Quality can be raised in some crops by lowering the mycotoxin growth (P<0.05) compared to the longer rotations. SCN populations did not differ among rotations. Quantification of F. virguliforme in soil using real- level through removal infected products. In the case of copra, the dried time PCR suggested a greater pathogen population in the 2-year rotation com- nutmeat of the coconut, hand sorting to remove Aspergillus flavus-contami- nated copra is an effective remediation strategy. However, typically only pared to the 3-year rotation, but the mechanisms behind the reduction in SDS about one third of A. flavus contaminants in plants are aflatoxigenic, so it need further clarification. These findings suggest that long-term crop rotations may offer an alternative management practice for reducing risk of SDS. would be useful to have a method to visually distinguish aflatoxigenic from non-aflatoxigenic A. flavus contamination of copra. We have applied to copra the cultural method for identifying aflatoxigenic A. flavus in which ammonia Identification of quantitative trait loci for partial resistance to exposure is used to raise the pH, changing the color of anthraquinone Phytophthora sojae in soybean N. ABEYSEKARA (1), R. Matthiesen (1), S. Cianzio (1), M. Bhattacharrya pigments associated with the aflatoxin biosynthetic pathway from yellow to a much more visible red. Aflatoxigenic A. flavus was readily differentiated from (1), A. Robertson (1) (1) Iowa State University, Ames, IA, U.S.A. non-aflatoxigenic A. flavus on copra by the appearance of red color after Phytopathology 102:S4.1 ammonia exposure, particularly along break lines. These studies suggest ammonia exposure would be a useful addition to aflatoxin remediation Stem and root rot caused by the oomycete pathogen Phytophthora sojae, is an practices in copra and possibly other crops. economically important disease of soybean across the world. The disease is managed primarily by planting cultivars with single-gene mediated resistance. Long-term crop rotations suppress soybean sudden death syndrome in Iowa However, this type of resistance is becoming ineffective due to the emergence N. ABDELSAMAD (1), G. C. Mbofung (1), A. E. Robertson (1), M. Liebman of new pathogen races. Partial resistance (PR) or field tolerance to P. sojae, (1), L. F. Leandro (1) which is polygenic in nature, has also been reported in soybean. It provides (1) Iowa State University, Ames, IA, U.S.A. broad-spectrum, low level of root resistance against all physiological races of Phytopathology 102:S4.1 the pathogen. Therefore, incorporation of PR into soybean cultivars would provide a more durable form of disease management. The main objectives of Sudden death syndrome (SDS) of soybean caused by Fusarium virguliforme is this study were to identify molecular markers linked to quantitative trait loci one of the most damaging diseases of soybean in the US. Management of SDS relies on selection of resistant varieties, cultural practices to improve soil (QTL) for PR to P. sojae (PRPS), and to validate the rice method as a more objective screening method for PR. Two recombinant inbred line populations drainage, and avoiding planting in cool, wet soils. The effectiveness of crop were developed by crossing the plant introduction, PI399036, with two germplasm lines, AR2 and AR3. PI399036 carries high level of PRPS. AR2 and AR3 show low PRPS but carry genes for resistance to iron deficiency chlorosis. Both populations were advanced to the F7 generation and screened The abstracts are published as submitted. They were formatted but not for PRPS using the rice method. Roots of both the P. sojae-infected and edited at the APS headquarters office. uninfected plants were evaluated 30 days after planting using a WinRhizo root scanner. Dry root and shoot weights were also obtained to quantify the levels http://dx.doi.org/10.1094/PHYTO-102-7-S4.1 of PR in the populations. Data analysis is on progress and the mapping data © 2012 The American Phytopathological Society will be presented. Vol. 102 (Supplement 4), No. 7, 2012 S4.1 A novel Marafivirus from Ranunculus repens kasugamycin and the biocontrol support registration of their products for the N. Abou Ghanem-Sabanadzovic (1), A. Lawrence (2), S. SABANADZOVIC (3) management of bacterial blast and these will be the first treatments ever (1) Institute for Genomics, Biocomputing and Biotechnology, Mississippi registered in the United States for effective management of this disease. State University, Mississippi State, MS, U.S.A.; (2) Institute for Imaging and Analytical Technologies, Mississippi State University, Mississippi State, MS, Occurance of resistance to respiratory inhibitiors in Corynespora U.S.A.; (3) Department of Biochemistry, Molecular Biology, Entomology and cassiicola isolates from Florida tomatoes Plant Pathology, Mississippi State University, Mississippi State, MS, U.S.A. H. M. ADKISON (1), E. Margenthaler (1), V. Burlacu (1), R. Willis (1), G. E. Phytopathology 102:S4.2 Vallad (1) Creeping buttercup plant (Ranunculus repens), displaying mosaic symptoms, (1) University of Florida Gulf Coast Research and Education Center, Wimauma, FL, U.S.A. collected during a survey on plant viruses present in the Great Smoky Phytopathology 102:S4.2 Mountain National Park was submitted to lab analyses in order to characterize the putative agent. Electron microscope observations of partially purified Target spot, caused by Corynespora cassiicola, is an important fungal disease preparations indicated the presence of putative empty and intact isometric of tomato in Florida. There are few published reports about pathogen diversity particles. Nucleic acid extracts from this sample reacted positively in RT-PCR and fungicide resistance for C. cassiicola. Observations at grower sites and in when tested with degenerate primers for viruses belonging to the family field trials have raised concerns about the efficacy of certain fungicides for Tymoviridae. Initial BLAST analyses indicated the presence of a novel virus, target spot management. Using an agar plug-based assay, 11 field isolates which prompted further characterization. Polyadenylated viral genome, of 6.6 were tested for sensitivity to azoxystrobin, boscalid, fluopyram, and kb in size, contains a single open reading frame potentially coding for a 237 K penthiopyrad. All isolates exhibited high levels of tolerance to azoxystrobin at polyprotein with signature motifs of the replication polyprotein and viral coat 50 µg/ml, and two isolates were tolerant to boscalid at 50 µl/ml. To confirm proteins. In phylogenetic analyses, performed on viral RdRp and CP, the virus our findings, tomato seedlings were treated with 0.5, 1.0, and 1.5 times the grouped with marafiviruses. In-depth comparisons of overall polyprotein maximum labeled field rates of azoxystrobin, boscalid, chlorothalonil, sequences and several domains showed that this virus, for which we propose fluopyram, mancozeb, and penthiopyrad, and inoculated with two boscalid- the name Ranunculus mosaic virus, is a new member of the genus Marafivirus sensitive and -insensitive isolates in growth room trials. All four isolates as it shares limited identies with known marafiviruses. showed an increase in disease severity greater than the control with treatment of azoxystrobin, regardless of the rate; whereas mancozeb performed better Plants vs. pathogens: VEGEVADERS—A game of infiltration and than chlorothalonil. All SDHI fungicides gave fairly consistent suppression of detection the two boscalid-sensitive isolates, while boscalid and penthiopyrad were
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