This article appears in the June 2017 issue of Potato Grower.
Vitamins are chemical compounds that our bodies need in small amounts to be healthy. We obtain vitamins from our diet, mostly from plant sources. Plants, too, need their vitamins to function properly. But unlike us, plants can make vitamins on their own. Vitamins have a wide range of essential functions, from antioxidants to energy producers. A specific group of vitamins, the B group, may offer a new potential strategy to control diseases in crops. Recent laboratory research in tobacco, grapevine, rice and cucumber has shown that application of vitamin B-1 prepares plants to fight off pathogen attacks more rapidly and efficiently. This mechanism is called priming and can somewhat be compared to vaccination in humans.
Potato virus Y (PVY) is an economically important disease of potato with a worldwide distribution that can potentially cause significant yield losses in solanaceous crops, including potatoes. The emergence of new strains of PVY in the U.S. in the last couple decades has made the disease ever more difficult to control. This issue prompted researchers at Oregon State University’s Hermiston Agricultural Research & Extension Center to test the potential use of vitamin B-1 to prevent PVY buildup and spread in potato. The research was recently published in the American Journal of Potato Research and was partly funded by the Oregon State University Agricultural Research Foundation.
Experiments were conducted in a greenhouse to have better control of environmental conditions. Researchers used virus-free Ranger Russet, a commonly grown variety in the Columbia Basin of Oregon and Washington. Plants were challenged with a recombinant strain of PVY, PVYN:O, by mechanical inoculation. They sprayed different concentrations of vitamin B-1 solutions that were applied at different intervals using a spray bottle until run-off. Each treatment was repeated three times.
The spread of the virus throughout the potato plants and the level of the virus were tracked by using immunological and molecular techniques. In general, results have been promising. The researchers’ data show that spraying vitamin B-1 on potato foliage can limit the level of PVY in the plant. While application of low concentrations of vitamin B-1 (338 parts per million) had little effect on the overall virus level in potato foliage regardless of the number of applications, intermediate concentrations of vitamin B-1 (3,380 parts per million) decreased the overall virus level in potato foliage about two-fold when applied twice, once before virus inoculation and once four weeks later.
The most dramatic decrease in virus level occurred when potato plants received two applications of the highest concentration of vitamin B-1 (33,800 parts per million). This latest treatment decreased the overall virus level about 80 times compared to the untreated check. Also, one application of the highest vitamin B-1 concentration decreased the virus level three times. Additional research is warranted to validate these findings in a field environment and to test the possibility of spraying vitamin B-1 to control other strains of PVY in other potato varieties.
It is important to note that vitamin B-1 application did not completely stop the virus spread, nor did it prevent foliar symptoms such as mosaic. Therefore, vitamin B-1 application should be considered as an additional tool, rather than a single, bulletproof strategy, compatible with efficient, integrated, sustainable management of PVY in potato production systems. In addition, current vitamin B-1 prices range from $100 to $200 per pound and may be cost prohibitive. A decrease in vitamin B-1 production costs is a prerequisite for the implementation of vitamin B-1 field application to control potato diseases.
Contributing authors of this study are Amber C. Vinchesi, Silvia I. Rondon and Aymeric Goyer with Oregon State University Hermiston Agricultural Research and Extension Center.