In their studies, the researchers examined sucrose transport in the thale cress, Arabidopsis thaliana, and in rice plants. In order to track down the function of the SWEET proteins, they switched off the corresponding genes in a series of plants. This enabled them to discover that, when their SWEETs do not work, plants have a considerably higher sucrose content in their leaves. "Because the sugar cannot be transported away, it accumulates in the leaf tissue, and other parts of the plant, like the roots and seeds, do not receive an adequate supply of sucrose," explains Alisdair Fernie from the Potsdam-based Max Planck Institute.
This discovery represents an important development for plant breeding as, in many cases, the parts of plants used by humans, like seeds and tubers, do not form any carbohydrates themselves but are, instead, supplied by the leaves. "We can now regulate these molecular pumps precisely and thereby increase the transport of sucrose to the plant seeds. One day, it may be possible to increase the harvest yield of agricultural crops in this way," explains Wolf Frommer from the Carnegie Institution. Moreover, the SWEETs provide a promising starting point for the protection of plants against pest infestations. Some pests, for example the bacterium Xanthomonas oryzae, which causes leaf streak in rice, misuse these transporters to access the plant's sucrose and feed on it themselves. For this reason, the scientists would now like to clarify the role of these transporters in pest infestation in greater detail.
The researchers suspect, moreover, that the corresponding pump proteins have a similar function in humans and animals. If confirmed, this would constitute a very important discovery for diabetes and obesity research, as the identity of the protein responsible f
|Contact: Alisdair Fernie|