Improving photosynthesis efficiency at lower temperatures

Project

Improving photosynthesis efficiency at lower temperatures

In the Netherlands different horticulture crops, such as tomato, cucumber and sweet peppers are mostly grown in heated greenhouses, and the energy used comprises 20% of the total production costs. Decreasing the greenhouse temperature by 2°C would save 16% of the energy consumed for the production of vegetables.

Heating the greenhouses is necessary in order to achieve high yields for the varieties that are currently available in the market. At lower temperatures key enzymes involved photosynthesis and sugar metabolism have a reduced activity and that leads to the accumulation of phosphorylated sugar in leaves (source organs). These sugars trigger feedback inhibition of photosynthesis and result in a limited/delayed fruit development.

Wild tomato accessions, in particular the ones naturally growing in cold and high altitude regions, are potential sources of enzymes with a higher activity at lower temperatures. Within this Towards Biosolar Project we are targeting enzymes involved in the reduction of sucrose accumulation in leaves in particular sucrose synthases (susy) and invertases (inv) (Figure 1), and characterizing the activities of different alleles from several tomato wild species.

Figure 1: Sucrose transport from source cell to sink cell. In source cell (leave), trio-phosphates generated from photosynthesis are partly converted into sucrose. Sucrose then can be used in the source cell or exported to sink cells through companion cell first, then sieve tube elements, and phloem. The transported sucrose through phloem is subsequently unloaded into sink cells (e.g. roots, fruits, tubers) and is processed further by several enzymes such as invertase and sucrose synthase.
Figure 1: Sucrose transport from source cell to sink cell. In source cell (leave), trio-phosphates generated from photosynthesis are partly converted into sucrose. Sucrose then can be used in the source cell or exported to sink cells through companion cell first, then sieve tube elements, and phloem. The transported sucrose through phloem is subsequently unloaded into sink cells (e.g. roots, fruits, tubers) and is processed further by several enzymes such as invertase and sucrose synthase.