Martina Zanella

Regulation of photosynthetic carbon metabolism.

The aim of my PhD project is to investigate the role of light in regulating the process of photosynthesis in plants. As autotrophic organisms, plants are capable of capturing light energy and converting it to chemical energy. They use this energy to transform water and atmospheric carbon dioxide into carbohydrates; a primary energy source both for the plants themselves and for animals and microorganisms that depend on them. The biochemical process by which plants make carbohydrates during photosynthesis is called the Calvin-Benson cycle, named after the scientists who discovered it. This cycle is driven by a set of enzymes – proteins found inside the chloroplast organelles in green leaves.

Being sessile organisms, plants have developed a variety of strategies to cope with the wide range of different environmental conditions that they experience, both diurnally and throughout their life cycle. One of the most obvious fluctuating parameters is the constant change in light intensity connected to the day/night cycle. Numerous regulatory mechanisms have evolved to adapt the speed at which the Calvin-Benson cycle operates to bring it into line with the input of light energy.

My research will focus on evaluating the impact of such light-dependent regulatory mechanisms using the model plant Arabidopsis thaliana. I will create a set of Arabidopsis transgenic plants that instead of their normal, regulated enzymes carry altered versions of the enzymes that are insensitive to light-dependent regulation. It is likely that photosynthesis in these plants will behave quite differently from the originals when exposed to variations in light intensity.

Because Arabidopsis is the number 1 model plant for scientific investigation, many different techniques are already available to help me achieve this goal quickly and thereby gain a much deeper understanding of the light regulatory effects on photosynthesis. This fundamental knowledge will be of great value not only for the scientific community, but also for more applied fields like agronomy and crop science. This is important because agriculture faces a looming challenge in terms of providing food, fibre and fuel for an increasing population, despite diminishing fossil fuel reserves and greater climate instability.