| Research Question | We wanted to investigate if Pcc could infest, then infect sweet potatoes, a different host than regular potatoes. We wanted to see if changing the host plant product affects the transfer of bacteria into the host, or if other plant products could become infected by Pcc. |
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| Predictions | Sweet potatoes will be susceptible to bacterial soft rot, as caused by Pcc, since they share some characteristics with common potatoes. Also, since Pcc is present in soil, so it is reasonable to believe that sweet potatoes will come into contact with the bacteria and become infested, then possibly infected. |
| Experimental Design | Materials: - Toothpicks marked at .75” from the bottom - 3 sweet potatoes (roughly 5-8” in length, 2-3” in width) - Paring Knife - 6 Zip-lock quart-sized freezer bags - A sharpie - Paper Towels - Inoculum - Tap Water Procedure: 1. Using the paring knife, cut each potato in half horizontally and separate so that one half is inoculated with the water, and the other half of the same potato is inoculated with the inoculum. Repeat with remaining two potatoes. 2. Taking one toothpick, dip it in the Tap water and insert it into the potato until you reach the .75” mark. Dip it back into the water and repeat until you have 5 holes. NOTE make sure you are dipping the toothpick back into the water before inserting it into the potato. 3. After there are 5 holes, dampen a paper towel, wrap it around the half and place it into a Zip-lock bag and close it tight. Place that bag into another, close it and label it “Control One.” Repeat with the remaining two halves, labeling them “Control Two” and “Control Three.” 4. Take the other half of the first potato you split and inoculate it with the inoculum the same way you did with the first three halves and the water. Repeat the same process of wrapping the towel around the half and double bagging the sweet potato. Label these bags with their corresponding control halves as “Inoculum One, Two, or Three.” 5. Place the bags on a tray and leave them sit for seven days before taking them out and observing the changes if soft rot has occurred. Variables: - Room Temperature: 80˚ Celsius - Only Sweet Potatoes were tested - All Toothpicks were marked .75” from the bottom - Exposed to part sun and Florescent lights - The inoculum was 2 weeks old has was refrigerated - Left some air in the bag when it was shut= |
| Conclusion | We conclude that further testing is required to accurately determine if bacterial soft rot, caused by Pcc, can occur in sweet potatoes. We may not have acquired bacterial soft rot in our sweet potatoes because the inoculum we used was collected from Russett potato's soft rot. We know that the incoculum was still potent, because it caused other groups to attain soft rot in their own Russett potatoes, so we think that maybe a different strain of bacteria causes soft rot in sweet potatoes. We don’t think we have enough evidence to make a confident conclusion on if whether or not sweet potatoes can in fact become infected with bacterial soft rot, as caused by Pcc. |
| Investigation Theme | PGST |
| Grade Level | High School Students (Grades 9,10,11,12) |
| School Name | Mercy McAuley High School |
| Session | Spring 2019 |
| About this Project | This group showed so much enthusiasm and went beyond their initial investigation to include anything that might be infecting potatoes, including mold. They posted many photographs and spent quality time communicating with their mentor. Though the results of the actual experiment were not completely clear, the group recognized that 'plants get sick, too', a concept that had not occurred to them previously. Darth Tater teammates approached the idea that plants get sick, too with enthusiasm and so many questions! Because of early observations they made in their initial potatoes, they used the experimental platform to include other plant infections, not only the potato soft rot. They communicated with their mentors frequently and posted many photographs that helped document the plant diseases they encountered. |