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Biomarkers for crop stress

Potato research in Canada is a mixture of puzzle pieces with each project aimed at defining one puzzle unit.


January 31, 2012
By Rosalie I. Tennison

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Potato research in Canada is a mixture of puzzle pieces with each project aimed at defining one puzzle unit. An Agriculture and Agri-Food Canada (AAFC) scientist is taking all the pieces and fitting them together to address crop stress. The objective is to develop tools for identifying sources of crop stress that will guide in-season management of potatoes. The research targets detection of nitrogen and water deficiency to give growers the ability to adjust inputs to the crop.

Using research results gathered from AAFC Research Centres across Canada and from partners at the University of Saskatchewan and the International Potato Centre in Peru, Dr. Helen Tai and a team of researchers are developing a tool that identifies what is causing the stress. The tool will also assist breeders to develop breeds that are nitrogen efficient.

“There are economic and environmental issues surrounding nitrogen management in potatoes,” Dr. Tai explains. “Fertilizer use presents an additional input cost for growers. Nitrate leaching and nitrous oxide emissions resulting from excess nitrate fertilizer use are an environmental problem.” An additional complication occurs under drought conditions because plants will undergo nitrogen deficiency even if sufficient quantities of nitrate is present in the soil since there is no water to solubilise it. So, indicators of both nitrogen and water use stress in potatoes are being developed.

“We are trying to develop a gene expression diagnostic tool that will help us measure the stress in a plant and, eventually, in a field that will help growers use water and nitrogen more efficiently,” Dr. Tai continues. Gene expression diagnostic tools are currently being used in medicine and adopting these technologies for agriculture is part of Dr. Tai’s research. The team is conducting field studies in Alberta, Saskatchewan, Manitoba, Quebec, New Brunswick, and Peru. These studies will examine the performance of the gene expression diagnostic across conditions of drought, variable nitrogen sources, and different potato varieties.

“We hope to demonstrate the utility of gene expression diagnostic biomarkers for crop management by the end of the project in 2013, but it will be longer than that before growers will be able to access the test themselves,” admits Dr. Tai. “What gene expression diagnostic offers is the potential to test for multiple stresses in one go. For example, drought, nitrogen and disease testing can be done all at once to allow growers to make better management decisions.” Stress can be caused by many factors, she explains, but, if growers can have more accurate determinations of what is causing it, they could make corrections before crop development is affected.

Dr. Tai admits that the tool will not solve all problems, but it is a step towards developing more efficient use of fertilizer inputs that can reduce the environmental impact of potato production. She suggests that growers can use the diagnostic tools to optimize use of fertilizer to plant needs rather than by scheduled applications.

The development of this molecular tool will give other researchers assistance with their research and what has been learned during its development can be used in other applications as well. Dr. Tai says work being done at Outlook, Saskatchewan, is focussing on varieties that are tolerant to lower levels of nitrogen and comparing them to varieties that require higher levels. The  gene expression diagnostic tool is being developed for indication of nitrogen use efficiency at this site and will be used to assist breeders in selection of high performance varieties.

“The research is advancing in part because of recent developments in the field of genomics,” Dr. Tai says. “The test we developed is very promising, and we are looking into ways to make it accessible to growers.” By combining puzzle pieces, Dr. Tai and the team are able to make progress on gene expression diagnostic markers and are looking forward to bringing the tool to other researchers, breeders, and to growers in the near future.