Resistance (R) genes have a proven record for protecting plants against biotic stress. A problem is parasite adaptation via Avirulence (Avr) mutations, which allows the parasite to colonize the R gene plant. Scientists hope to make R genes more durable by stacking them in a single cultivar. However, stacking assumes that R gene-mediated resistance has no fitness cost for the plant. We tested this assumption for wheat's resistance to Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae). Our study included ten plant fitness measures and four wheat genotypes, one susceptible, and three expressing either the H6, H9, or H13 resistance gene. Because R gene-mediated resistance has two components, we measured two types of costs: the cost of the constitutively-expressed H gene, which functions in plant surveillance, and the cost of the downstream induced responses, which were triggered by Hessian fly larvae rather than a chemical elicitor. For the constitutively expressed Hgene, some measures indicated costs, but a greater number of measures indicated benefits of simply expressing the H gene. For the induced resistance, instead of costs, resistant plants showed benefits of being attacked. Resistant plants were more likely to survive attack than susceptible plants, and surviving resistant plants produced higher yield and quality. We discuss why resistance to the Hessian fly has little or no cost and propose that tolerance is important, with compensatory growth occurring after H gene-mediated resistance kills the larva. We end with a caution: Given that plants were given good growing conditions, fitness costs may be found under conditions of greater biotic or abiotic stress.
Before embarking on the 5-10 yr effort it can take to transfer plant resistance (R) genes to adapted crop cultivars, a question must be asked: is the pest a sufficient threat to warrant this effort? We used the recently discovered female-produced sex pheromone of the Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae),to explore this question for populations in the Upper Great Plains. Methods for pheromone trapping were established and trapping data were used to explore geographic distribution, phenology, and density. The pheromone lure remained attractive for up to 10 d and only attracted male Hessian flies. Traps placed within the crop canopy caught flies but traps placed above the crop canopy did not. Hessian flies were trapped throughout North Dakota starting in the spring and continuing through the summer and autumn. Densities were low in the spring but increased greatly during the early part of the summer, with peak adult emergence taking place at a time (July/August) when spring wheat was being harvested and winter wheat had not yet been planted. In the autumn, adults were found at a time when winter wheat seedlings are growing. The discovery of flies on Conservation Reserve Program land supports the idea that pasture grasses serve as alternate hosts. We conclude that the Hessian fly is a risk to wheat in the Upper Great Plains and predict that global warming and the increasing cultivation of winter wheat will add to this risk.
We studied whether adaptation of the Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae), to plant resistance incurs fitness costs. In this gene-for-gene interaction, adaptation to a single H resistance gene occurs via loss of a single effector encoded by an Avirulence gene. By losing the effector, the adapted larva now survives on the H gene plant, presumably because it evades the plant's H gene-mediated surveillance system. The problem is the Hessian fly larva needs its effectors for colonization. Thus, for adapted individuals, there may be a cost for losing the effector, with this then creating a trade-off between surviving on H-resistant plants and growing on plants that lack H genes. In two different tests, we used wheat lacking H genes to compare the survival and growth of a nonadapted strain to two H-adapted strains. The two adapted strains differed in that one had been selected for adaptation to H9, whereas the other strain had been selected for adaptation to H13. Tests showed that two H-adapted strains were similar to the nonadapted strain in egg-to-adult survival but that they differed in producing adults with smaller wings. By using known relationships between wing length and reproductive potential, we found that losses in wing length underestimate losses in reproductive potential. For example, H9- and H13-adapted females had 9 and 3% wing losses, respectively, but they were estimated to have 32 and 12% losses in egg production. Fitness costs of adaptation will be investigated further via selection experiments comparing Avirulence allele frequencies for Hessian fly populations exposed or not exposed to H genes.
The Medical Computer Facility at the Fox Chase Cancer Center has installed X-terminals in patient examination rooms and at nursing stations for clinical data access by physicians and nurses. The X-terminals are connected to UNIX operating system RISC processors via Ethernet. The RISC processors communicate with databases on a minicomputer cluster. Simultaneous presentation of textual (e.g., pathology and radiology reports) and graphical (e.g., clinical laboratory results) clinical data is provided under X-Windows. CT and MRI images can also be displayed in windows. Our experiences implementing X-terminal clinical workstations in a production environment will be discussed.
e17512 Background: Cancer awareness month campaigns are a health promotion tool used to increase public awareness about a specific cancer, its prevention, and treatment. Cancer awareness month campaigns could be most impactful in promoting awareness of cancers for which established screening guidelines exist. Currently, the United States Preventive Task Force endorses screening the general population for colon, cervical and breast cancers. We aimed to assess the effectiveness of campaigns by identifying internet search volume and monthly cancer diagnoses. Methods: GoogleTrends was utilized to identify the relative monthly volume of search terms from 2004 to 2009 as a proxy for public awareness. Search trends for“breast cancer”, “colon cancer”, and “cervical cancer” were analyzed and an average monthly search volume index (SVI) was determined. Surveillance, Epidemiology and End Result (SEER) data was analyzed during the same time period. These data were compared using Pearson's correlation coefficient and the chi square test for seasonality. The monthly trends were compared to corresponding cancer awareness month campaigns (breast cancer-October, colon cancer-March, cervical cancer-January). Results: Internet search volume was highest for colon cancer and breast cancer in the respective cancer awareness campaign months. The frequencies of breast cancer and colon cancer diagnoseswere not significantly higher in the respective cancer awareness months. Cervical cancer search volume and cancer diagnoses did not correlate with awareness campaign months. Search volume and cancer diagnoses were not well correlated for breast cancer (r=0.089) or cervical cancer (r=0.228); however, they were significantly correlated for colon cancer (r=0.386; p-value=0.0008). Conclusions: Cancer awareness month campaigns appear to raise public awareness as estimated by internet search volume for breast cancer and colon cancer. Cervical cancer awareness month campaigns do not have the same effect. There is no significant correlation between cancer awareness campaign months and cancer diagnosis incidence for either breast cancer or cervical cancer, whereas there is a significant correlation for colon cancer.
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