2016_02: Reis and Selenium

What is the topic?

Selenium is the mysterious brother of Sulphur. It is not really clear, for what purpose it is needed, but it is necessary in small amounts. Selenium insufficiency concerns large areas - for instance the West of China or Finnland. Other regions, such as the Indian Punjab, suffer instead from selenium toxicity. The transition from insufficiency to overdose is - comparable to other trace elements, such as Zinc - very narrow. To add Selenium to the fertiliser would be an option, but this would require knowledge about uptake and distribution in the plant. Rice as central staple crop of this planet is of special interest in this context. We therefore investigated, collaborating with the geochemists at KIT, the uptake of Selenium into rice. First, an experimental system had to be developed that allows to measure uptake under standardised conditions. This was far from trivial, but after all a closed container system for rice seedlings allowed to generate high-quality data. Using this system, we could show that uptake and mobility within the plant depends strongly on the Selenium species - Selenite behaved quite differently from Selenate. Further, the efficiency of uptake was strongly altered by competition with other nutrients. The toxicity observed for high concentrations of Selenium, was actually not caused by Selenium itself, but by the depletion of other elements that were outcompeted by Selenium from the uptake transporters. Our future cooperation will therefore try to understand this uptake in more detail with the long-term goal to improve the uptake of Selenium into rice by molecular breeding.

Publication

123. Nothstein AK, Eiche E, Riemann M, Nick P, Winkel LHE, Göttlicher J, Steininger R, Brendel R, v Brasch M, Conrad G, Neumann T. Tracking Se Assimilation and Speciation through the Rice Plant - Nutrient Competition, Toxicity and Distribution. PloS ONE PLoS ONE 11, e0152081 - pdf