At the Gardens:
For our third trip to the UAB gardens we were on a mission to find plants infected with fungal or bacterial pathogens. Due to recent rains (both fungus and bacteria thrive in moisture rich locations) and armed with our newly acquired knowledge of plant pathogens, we found several great examples of both. We also had a bonus: a possible mosaic virus infection.
While at the gardens we also learned how attributes from a pathogen were differing from those of a parasite. The holes in the leaf below were thought to be caused by aphids, a parasite, not a pathogen.
We then took our pathogen infected plants back to the lab to process our results.
In The Lab:
The bacterial infected leaves were first cut into four small squares, dipped into bleach, then water, and finally placed into a small tube containing sterile water and a grinding ball. After the contents of the tube were finely ground, a small amount was placed into a dilution tube labeled 1:10. The contents of that tube were shaken, then a sample of that solution was placed into another dilution tube labeled 1:100. From that tube, another sample was added to a final tube labeled 1:1000.
We then placed ~0.5 ml of the liquid from each tube into YPD medium plates labeled with the same name as its corresponding tube (1:10, 1:100, 1:1000). Using glass beads, we made sure that the solutions were evenly distributed around each plate.
The plates were placed into an incubator. Results should show up within 2 days.
To process our leaves with fungal infections, we started out like with bacteria by cutting the leaves into small pieces, then dipping those pieces in bleach.
These pieces are placed into a V8 medium plate. V8 is used as the agar because it is an excellent substance to promote fungal growth. The plates are placed in the incubator and results should be expected in 3 to 7 days.
Finally, just like we did in “Garden Investigation Trip,” to check our leaf for mosaic virus, we used a kit designed to test for a viral infection. The top pink control line showed up almost immediately, but it took nearly two hours for a very faint line to appear below that control line. The line is so faint that it does not appear in the photo.
The entire experience of the day was fun and I can’t wait to get out into nature to try to find phytopathogens on my own!