Press release: A single gene raises the usable caloric value of grain

Nr. 25/2013 - 19.02.2013

Researchers discover an enzyme mutation that can improve our food security

(pug) An international researcher's team affiliated with the University of Göttingen has found a genetic mutation in an enzyme that naturally enhances the caloric value and starch digestibility of the cereal grain sorghum. In our current times of expanding populations and forecasts of climatic change scenarios, improvements such as these are particularly important for agriculture and are ultimately necessary to further increase food production to cover global nutritional needs and ensure food security. These results have been published in the prestigious journal Nature.

Widespread malnutrition of the population is especially characteristic of the African continent. In many regions of Africa, the grain species Sorghum bicolor is an indispensable staple food because it is very heat-resistant and drought-tolerant. Due to the exceptionally harsh climatic conditions, it is either very difficult to cultivate other grain species or the yields are extremely low. A central problem of sorghum grain, however, is that it supplies proportionately fewer calories and thus cannot ensure Africa's food security.

To date, the focus of research has tended to ignore the aspect of improving the caloric value of staple foods, an enhancement that would be of great relevance in Africa. This is where starch metabolism plays a major role, considering that starch constitutes the majority of calories in grain. "We have identified a naturally occurring genetic mutation in pullulanase, an enzyme involved in starch metabolism that improves the digestibility of sorghum grain and increases its caloric value," explained Anna Kristina Rada, Master's candidate at the Department of Crop Sciences at Göttingen University. She conducted field trials in Gatton (Queensland, Australia) during a research fellowship at the University of Queensland.

Gene mutations that are instrumental in starch metabolism can sometimes have adverse effects on crop yield. Consequently, the benefit of such genes for use in modern breeding programs is negligible. "We were lucky that the genetic mutation we discovered in the pullulanase enzyme improved digestibility, regardless of genotypic background and without negatively affecting the plant's growth or yield. That means that this gene could enjoy virtually unlimited utilization for modern plant breeding and thereby increase the usable caloric value of sorghum grain," added Anna Rada. The gene therefore has the potential to enhance food security, particularly in regions characterised by extreme farming conditions – without exploiting scarce resources such as arable land and water.

Original publication: Gilding et al. (2013) “Allelic variation at a single gene increases food value in a drought-tolerant staple cereal.” Nature Communications, http://dx.doi.org/10.1038/ncomms2450

Contact address:
Maik Eckardt
Georg-August University Göttingen
Press, Communications and Marketing
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Phone +49 (551) 39-7827
E-mail: maik.eckardt@zvw.uni-goettingen.de
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