We all know it: That one plant on the windowsill that we provide with the most pleasing light and water conditions, that we care for thoroughly and that still goes limp... just unless you remember to add that tiny bit of fertilizer to its soil.
Plants have the sublime ability to capture the energy of sunlight and turn it into chemical energy by fixing atmospheric carbon dioxide into sugar, a form of energy that can be stored and used to produce biomass according to the plant’s need. This process is called photosynthesis. Facing the struggle of feeding an increasing world population, the improvement of photosynthesis in crop plants is believed to be a helpful tool to build more productive plants. This idea is not too odd: evolution has reacted to unfavorable environmental conditions by improving the photosynthetic apparatus of many different plant species which enhanced the plant’s fitness. Based on its metabolic adaptions, this mechanism is referred to as C4 photosynthesis. Understanding the process of evolution towards C4 photosynthesis and pushing the relevant buttons in our less-efficient crop plants can lead to our desired yield increase.
But wait… what did our moody house plant teach us? Optimal use of sunlight and atmospheric CO2 is obviously not enough to satisfy our green roommate. Any living organism relies on a broad spectrum of nutrients to develop and maintain metabolic processes. The importance of a well-balanced diet for human health is omnipresent and, in fact, the same applies for plant nutrition. Plants derive the vast amount of their nutrients from the soil and one major nutrient that is essential for plant metabolism is sulfur. Sulfur takes over a wide variety of important tasks in animals and plants. Incorporated in amino acids, the essential building blocks of proteins, sulfur is involved in all life-depending processes in all living organisms. As an element of non-essential but advantageous metabolites it protects the plant from herbivore attack or prevents the plant equivalent of sunburn. Undernourishment can therefore have disastrous consequences for the plant.
When you consider the importance of photosynthesis and nutrition for the plant’s wellbeing, important questions arise: Which role does the plant’s supply with sulfur play in the evolution of C4 photosynthesis? How does the higher productivity affect all the metabolic events around this essential nutrient? Or does sulfur nutrition even influence the evolution of this complex trait itself? Which role does the environment play? And would a C4 plant on the windowsill be more forgiving if we forget to buy that new pack of fertilizer? Within the CEPLAS C4 photosynthesis division we aim to answer these questions, contributing to the overall goal to unravel the building blocks of a C4 plant.
Silke Weckopp, Botanical Institute, University of Cologne
Under the heading Planter’s Punch we present each month one special aspect of the CEPLAS research programme. All contributions are prepared by our young researchers.
Hibberd, J. M., Sheehy, J. E. and Langdale, J. A. (2008). "Using C4 photosynthesis to increase the yield of rice-rationale and feasibility." Curr Opin Plant Biol 11(2): 228-231. [Abstract]
Koprivova, A., Melzer, M., von Ballmoos, P., Mandel, T., Brunold, C. and Kopriva, S. (2001). "Assimilatory sulfate reduction in C3, C3-C4, and C4 species of Flaveria." Plant Physiol 127(2): 543-550. [Abstract]
Weckopp, S. C. and Kopriva, S. (2014). "Are changes in sulfate assimilation pathway needed for evolution of C4 photosynthesis?" Front Plant Sci 5: 773. [Abstract]