A WAY of introducing genetics into plants which allow them to better utilise photosynthesis, is being championed by scientist in Holland.

Researchers there have found a method that can completely replace the organelles (specifically, the chloroplasts, which are essential for photosynthesis, and mitochondria, which generate energy) of one plant with the organelles of another plant, while the chromosomes remain unchanged. They conducted their research using the thale cress plant (Arabidopsis thaliana) as the model.

It has always been assumed that each plant carries chloroplasts that contribute to the optimum growth and development of the plant. However, this has been shown to be false, as demonstrated by researchers at Wageningen University and Research (WUR), in a scientific publication published this week in Nature Plants.

Researcher Erik Wijnker explained: “Now that it is possible to replace the organelles of a plant using an efficient genetic trick, we can compare the original plants with plants that have the ‘new’ organelles. This makes it easy to determine which new combinations of organelles and chromosomes lead to the best plant properties.

"For example, for a certain type of chloroplast, we now know beforehand that, if we put them in a thale cress, photosynthesis will be improved.”

Plants use only a fraction of absorbed sunlight for photosynthesis. Improving that process is the key to more efficient plant growth, which can reduce the footprint of agriculture on the environment, said the research paper.

For many years it was thought that photosynthesis could not be improved, but recently various methods have been developed, including at WUR, to improve plant photosynthesis to such an extent that more of the captured sunlight can be used for biomass production. If this is successful, plants with improved photosynthesis can make an important new contribution to tackling food shortages, but without causing any further damage to the climate.

At the moment, virtually no use is made of the natural variation in chlorophlasts and mitochondria in commercial plant breeding. Researcher Pádraic Flood said: “There is an enormous natural variation in chloroplasts, but researchers lacked simple methods to determine which chloroplasts possessed the desired properties.”

The contribution of chlorophyll and mitochondria to the growth of the plant is notoriously difficult to assess. The method described in the publication makes this easier and in turn, makes using this knowledge much more accessible to breeding businesses.

PhD candidate Tom Theeuwen added: “The trick we have used for thale cress is based on genetic modification and its use for crops is subject to strict rules in Europe, but with the current modern breeding methods, it is fortunately highly possible to make similar new combinations of organelles and chromosomes in a short period of time.

"Now that we have shown that this can lead to plants that perform better, a number of companies are interested to know whether this also applies to crops. It offers us a new way of investigating whether we can better understand and improve plant photosynthesis, by creating and testing new combinations.”