Effects of thiamine treatment on potato to control potato virus Y and zebra chip

In 2012, Oregon State harvested almost 17,000 hectares of potatoes with a production value of $172,838,000, making potatoes the seventh most important commodity for Oregon. Potato Virus Y (PVY) and Liberibacter, or Zebra Chip (ZC), are major potato pathogens affecting yield. Thiamine, a water-soluble B-complex vitamin (a.k.a. vitamin B₁₎ has been shown in many crops to boost the plant’s immunity, thereby increasing resistance against pathogens by inhibiting disease progression and reducing pest populations. Our objectives for this study were to test the effect of thiamine application on potato resistance to PVY and ZC, two diseases vectored by aphids and potato psyllids, respectively. We conducted screenhouse studies to determine whether thiamine provided resistance against aphids/PVY and against psyllids/ZC. We tested different densities of aphids and psyllids (0, 1, 5, 10/plant) on potatoes using four treatments of thiamine at different concentrations (0 mM, 1 mM, 10 mM, 50 mM). On plants with disease-positive insects (“hot” insects), we monitored disease symptoms and progression by collecting leaves and performing ELISA and RT-PCR. On disease-free plants (“clean” insects), we monitored insect feeding symptoms and damage to the plant by counting insect progeny to determine reproductive success on the host. We will report on the effect of thiamine application on plant resistance to PVY and ZC, and on insect behavior.