Location: Sugarbeet and Potato Research
2016 Annual Report
Accomplishments
1. Gibberellins are involved in 1,8-cineole-mediated inhibition of tuber sprout growth. At harvest and for an indeterminate period thereafter, potatoes are in a state of physiological dormancy and will not sprout. However, dormancy is lost during storage yielding sprout growth which is accompanied by changes in tuber physiology leading to loss of nutritional and processing quality. Suppression of sprout growth is essential in successful potato storage management. Unlike other registered sprout inhibitors, the natural product cineole is known to reversibly mediate inhibition of sprout growth, suggesting a non-herbicidal mechanism of action that may be related to exploitable hormonal control. ARS scientists in Fargo, North Dakota determined that cineole inhibits sprout growth, in part, through reversible inhibition of gibberellin biosynthesis. These results are important in the future development of modern technologies to control sprouting in bulk stored potatoes.
2. Wound healing in potatoes. Potato tubers are unavoidably skinned and bruised (wounded) during harvest/handling and require rapid wound-healing (WH) to avoid costly rot type infections, nutritional deterioration and other losses during storage. Currently, there are no means available to hasten WH; yet little is known about the biological mechanisms regulating the critical WH processes for rapid development of an initial protective barrier (suberin) and subsequent initiation of cell division required for development of a more durable protective wound periderm. ARS scientists in Fargo, North Dakota along with a Pennsylvania State University biologist, determined the wound-induced changes in hormones that are required for this cell division process. Although the hormones cytokinin (CK) and indole acetic acid (IAA) are required in the regulation of cell division, the existence of certain CK related products indicated that there was only a fleeting presence of biologically active CK during WH, which suggested tight CK mediated regulation. IAA content increased markedly at 7 days after wounding when cell division processes fully initiated, suggesting that its regulatory role was less sensitive. Notably, gibberellin hormones, which are typically involved in growth, were not present during WH and consequently do not play a role in WH processes. These results provide new insight into the regulation of wound periderm formation, which is critical in the development of new technologies to hasten WH and thereby reduce rot and nutritional/quality deterioration for growers, processors and consumers.
Review Publications
Lulai, E.C., Suttle, J.C., Olson, L.L., Neubauer, J.D., Campbell, L.G., Campbell, M.A. 2016. Wounding induces changes in cytokinin and auxin content in potato tuber, but does not induce formation of gibberellins. Journal of Plant Physiology. 191:22-28.
Suttle, J.C., Olson, L.L., Lulai, E.C. 2016. The Involvement of Gibberellins in 1,8-Cineole-Mediated Inhibition of Sprout Growth in Russet Burbank Tubers. American Journal of Potato Research. 93(1):72-79.
Suttle, J.C., Campbell, M.A., Olsen, N.L. 2016. Potato tuber dormancy and postharvest sprout control. In Pareek, S. Postharvest Ripening Physiology of Crops. CRC Press. 449-476.
