HerbBi - Herbicide-mediated biphasic responses in plants

• Applicant: Privatdozentin Dr. Regina Belz
• Subject Area: Plant Breeding and Plant Pathology
• Term: from 2010 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 175351470

Biphasic or else hormetic responses signify stimulatory effects on organisms by low-doses of stressors including toxins such as herbicides that change to inhibitory effects at higher doses. This phenomenon of hormesis is becoming a more and more widely accepted occurrence in many toxicological disciplines. In agriculture, pesticide-induced hormesis in plants is known for quite some time and in particular, the appearance of hormesis with the currently most widely used herbicide glyphosate re-entered an interest of research in this area. Herbicide hormesis is important for crop production in two ways. On the one hand, low doses of herbicides can be used to promote crop performance and/or yield. On the other hand, hormesis can occur as side effect of regular herbicide applications when crops, weeds, or wild plants are inadvertently exposed to low doses.At present, a commercial use of herbicide hormesis is considered too risky for general crop production as for most crop/herbicide combinations, the phenomenon is too unpredictable in the field where numerous factors influence the hormetic outcome. Recent findings, however, indicate that herbicide hormesis as a secondary effect after regular applications almost certainly occurs and may have profound impacts in economic, environmental, ecological, and/or evolutionary terms. Since, these low-dose impacts were given little consideration in the past, our knowledge in this area is still marginal. Therefore, hormetic side effects of regular herbicide applications represents the central objective of this project. Our recent findings substantiate herbicide hormesis a possible contribution to the population dynamics of herbicide resistant weeds, a possible selection pressure for and against certain subpopulations of the same weed species within a field leading to a displacement of the size distribution within a total population, and a possible role in cocktail effects of mixed low-dose exposures that are still hard to capture and mathematically predict. Assessing the ecological and practical relevance and importance of these aspects is a priority research area of the current project. In addition, putative transgenerational effects in herbicide-boosted plant populations are addressed. Laboratory, greenhouse and semi-field experiments are conducted to unravel these aspects in close cooperation of an interdisciplinary and international team of collaborators with expertise in weed management, plant physiology, environmental ecology, and mathematical modeling. Based on this, the overall aim of the research project HerbBi is to leverage a fundamental under-standing of herbicide hormesis to better recognize its full impact on crop production, weed control and ecology of non-target plants. As hormesis is widespread across biological and toxicological sciences, the results are similarly important for agronomists as for anyone dealing with chemical stress in medicinal, toxicological, and ecological sciences.

• DFG Programme: Research Grants