@article{sullivan_parks_cubeta_gallup_melton_moyer_shew_2010, title={An Assessment of the Genetic Diversity in a Field Population of Phytophthora nicotianae with a Changing Race Structure}, volume={94}, ISSN={["1943-7692"]}, DOI={10.1094/pdis-94-4-0455}, abstractNote={ One hundred fifty-three isolates of Phytophthora nicotianae that were collected over a 4-year period from a single field were subjected to amplified fragment length polymorphism (AFLP) analysis to investigate the effect of different types of resistance in tobacco (Nicotiana tabacum) on genetic diversity in the pathogen population. No race 1 isolates were detected in the field prior to initiating the study, but the race was present in multiple plots by the end of the 4-year period. There were 102 race 0 isolates and 51 race 1 isolates characterized. Seventy-six of the 153 isolates had a unique AFLP profile, whereas the remaining 77 isolates were represented by 27 AFLP profiles shared by at least two isolates. Isolates of both races were found in both the unique and shared AFLP profile groups. Twenty-three of the AFLP profiles were detected in multiple years, indicating a clonal component to the pathogen population. Race 1 isolates that were detected over multiple years were always obtained from the same plot. No race 1 profile was found in more than one plot, confirming the hypothesis that the multiple occurrences of the race throughout the field were the result of independent events and not pathogen spread. Three identical race 0 AFLP profiles occurred in noncontiguous plots, and in each case, the plots contained the same partially resistant variety. Cluster analysis provided a high level of bootstrap support for 41 isolates in 19 clusters that grouped primarily by race and rotation treatment. Estimates of genetic diversity ranged from 0.365 to 0.831 and varied depending on tobacco cultivar planted and race. When averaged over all treatments, diversity in race 1 isolates was lower than in race 0 isolates at the end of each season. Deployment of single-gene resistance initially decreased genetic diversity of the population, but the diversity increased each year, indicating the pathogen was adapting to the host genotypes deployed in the field. }, number={4}, journal={PLANT DISEASE}, author={Sullivan, M. J. and Parks, E. J. and Cubeta, M. A. and Gallup, C. A. and Melton, T. A. and Moyer, J. W. and Shew, H. D.}, year={2010}, month={Apr}, pages={455–460} }
 @misc{burkholder_g. m._g._a._h. a._d. w._m. w._m. j._p. v._e. h._et al._2007, title={Phytoplankton and bacterial assemblages in ballast water of US military ships as a function of port of origin, voyage time, and ocean exchange practices}, volume={6}, number={4}, journal={Harmful Algae}, author={Burkholder, J. M. and G. M., Melia and G., Cohen and A., Bowers and H. A., Oldach and D. W., Parrow and M. W., Sullivan and M. J., Zimba and P. V., Allen and E. H., Kinder and et al.}, year={2007}, pages={486–518} }
 @article{sullivan_melton_shew_2005, title={Fitness of races 0 and 1 of Phytophthora parasitica var. nicotianae}, volume={89}, ISSN={["0191-2917"]}, DOI={10.1094/PD-89-1220}, abstractNote={ Deployment of tobacco (Nicotiana tabacum) varieties with complete resistance to race 0 of Phytophthora parasitica var. nicotianae has led to a rapid increase in the field populations of race 1 in North Carolina. In a field study, population levels of race 1 decreased relative to race 0 when cultivars with partial resistance to both races were planted, suggesting that race 1 isolates were less fit than race 0 isolates. Experiments were conducted to quantify differences in aggressiveness and survivability of the two races. Tobacco varieties with low, moderate, or high levels of partial resistance were inoculated with 60 pathogen isolates, and symptom development was monitored for 3 weeks. Race 0 isolates were more aggressive than race 1 isolates on cultivars with moderate or high levels of partial resistance; incubation periods were shorter and root rot severity was greater with race 0 isolates. Isolates of race 1, however, caused greater stunting of plants with moderate and high levels of partial resistance than race 0 isolates. Field microplots were infested with either a single race or an equal mixture of each race. Soil samples were collected at the end of two growing seasons and again the following spring. Pathogen populations declined from 40 to 80% during winter months, but population declines for race 0 were lower than for race 1 in each treatment over each winter. Race shifts from race 1 to race 0 that were observed in the presence of cultivars with partial resistance appear to be primarily the result of differences in aggressiveness of the races, with a possible minor effect of enhanced overwintering survival of race 0 compared with race 1. }, number={11}, journal={PLANT DISEASE}, author={Sullivan, MJ and Melton, TA and Shew, HD}, year={2005}, month={Nov}, pages={1220–1228} }
 @article{sullivan_damicone_payton_2002, title={The effects of temperature and wetness period on the development of spinach white rust}, volume={86}, ISSN={["0191-2917"]}, DOI={10.1094/PDIS.2002.86.7.753}, abstractNote={ Experiments were conducted in controlled environments to determine the influence of temperature and duration of wetness on development of white rust of spinach. Plants of the susceptible cv. Kent were exposed to temperatures of 6 to 28°C and interrupted wetness periods that totaled 3 to 84 h following inoculation. Disease severity was assessed following further incubation in a greenhouse at 20 to 30°C. Disease was observed at all temperatures and increased with wetness duration. The optimum temperature for disease development ranged from 12 to 18°C. Only 3 h of wetness were required for disease development at 12 to 22°C. A minimum wetness period of 6 to 12 h was required for disease development at suboptimal temperatures. A multiple regression model describing the response surface of arcsine square root transformed disease severity was developed that had significant quadratic wetness effects, cubic temperature effects, and interaction between temperature and wetness. The resulting polynomial model provided a good fit to the observed data, accounting for 89% of the variation in transformed disease severity. }, number={7}, journal={PLANT DISEASE}, author={Sullivan, MJ and Damicone, JP and Payton, ME}, year={2002}, month={Jul}, pages={753–758} }