Discussion
There were definitely differences between the Xap isolates. However, there were some identical isolates in relation to fuscous cultures and seed origin. The geography of the isolates did have an impact on some of the isolates. For example, Xap 69 and 70, which are both from Colorado had virtually identical DNA. This might also suggest a relationship between the seed origin and the bacterial DNA. Since the bacteria samples came from the same state, it is possible that the seed for both samples came from the same origin. More evidence of a relationship between seed origin and DNA was found in Xap 29. Xap 29 was genetically an “outlier”, it was very genetically different from the other samples. Although it was grown in Manitoba, the bean cultivar was Peruano Higuera T, a seed from Mexico. This would suggest that the DNA is affected by the seed origin more than the growing region. And also that if we had been able to assess Mexican isolates, there quite likely would have been DNA similarities between Xap 29 and the Mexican isolates.
Xap samples 46 and 68 are identical, and they are from Alberta and Manitoba respectively. Xap samples 50 and 82 were also identical to each other and they are also from Alberta and Manitoba respectively. This would suggest that there might be some infected seed transportation between the two provinces.
Cultures that were identical and similar were also sometimes fuscous. There was strong similarity between the fuscous cultures, Xap 5, 11, 21 and 65. Xap samples 5 and 11 were genetically identical despite the fact that they came from Ontario and Saskatchewan respectively. This shows that the location of the growing region in fuscous cultures has little or no effect on the DNA. This also shows that the fuscous cultures are genetically different from the normal Xap cultures, as well as in the Petri dishes. This might also suggest that the fuscous cultures are indeed a subspecies and not a separate species as they are related to other normal strains of Xap bacteria. The fuscous strains also mostly showed high aggressivity, over 50 mm squared lesion area, on tolerant bean cultivars. Xap 23 seemed to be unique, it was aggressive just like the fuscous cultures, yet it was in a different cluster. The agarose gel shows that Xap 23 has some bands that are present in the fuscous cultures(Xap 5,11,21 and 65) and it also has some bands that are present in Xap 25 and 27, normal strains of Xap. This suggests that Xap 23 may be a hybrid of the normal Xap isolates and the fuscous cultures.
The highly aggressive cultures seemed to be mostly fuscous with the exception of Xap 2, 23 and 29. The highly aggressive seemed to be clustered together with the exception of Xap 29 and 81. The moderate and low aggressivity isolates seemed to be spread out between the other two clusters.