Occurrence of Race 3 of Phytophthora nicotianae in North Carolina, the Causal Agent of Black Shank of Tobacco.

Black shank, caused by the oomycete Phytophthora nicotianae, causes significant annual yield losses in tobacco. Race 3 of P. nicotianae is reported here for the first time from North Carolina. It was identified from a North Carolina tobacco field with a history of tobacco varieties with Phl gene resistance and numerous field sites with no known deployment of varieties with the Phl gene. Race 3 was originally described from cigar-wrapper tobacco in Connecticut in the 1970s, but has not been reported in any other location since. Race 3 was defined as overcoming the Phl gene from Nicotiana longiflora but not the Php gene from N. plumbaginifolia. Stem and root inoculations were conducted on a set of host differentials to determine the virulence of North Carolina isolates. Stem inoculation was unable to distinguish between races 0 and 3 of P. nicotianae and is not a reliable method of identifying these virulence types. Race 1 gave a unique phenotype using stem inoculation. Root inoculation was the only reliable means of distinguishing between races 0 and 3. This is the first report of race 3 in North Carolina and the first report of damage to seedlings from root inoculations and to plants containing the Phl gene in naturally infested soil.

An Assessment of the Genetic Diversity in a Field Population of Phytophthora nicotianae with a Changing Race Structure.

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.

Radon in treatment of infiltrating carcinoma of urinary bladder.

Shown here are the results from the use of radon in the treatment of 146 patients with infiltrating carcinoma of the bladder. Ninety-four per cent of the tumors had invaded the muscle of the bladder; 54 per cent were Stage B2 or worse. Ninety per cent of the radon implantations were done cystoscopically. Twenty-one per cent of the patients survived five years or longer, free of recurrence. An additional 8 per cent were cured by follow-up treatment of recurrences. Complications and morbidity are minimal. Survival results compare favorably with more dangerous and debilitating methods of treatment.

Total retropubic prostatectomy for carcinoma of the prostate.

Results in 96 patients who had total retropubic prostatectomy were reviewed. The most common complications were impotence and difficulty with urinary control. The most serious were rectal injury and vesical neck contracture. Twenty-eight of 33 patients who were followed for five years after operation and eight of twelve who were followed for ten years were alive without evidence of recurrence of cancer. Evidence of recurrence was found only in patients in whom cancer had spread beyond the parenchyma of the prostate before operation. There were no operative deaths.