Text by Lauri Laanisto
Jeroni Galmes´ name has so far been missing from this blog. I don´t understand how… Anyhow, he is one of the guys from the Party islands (Majorca, to be more precise). There lives and works a bunch of plant physiologist with whom Ülo has been cooperating for a long time already. Jaume Flexas being probably the most familiar for the reader.
Jeroni´s work is a bit difficult for me to explain. It´s pretty hardcore physiology, typically related to photosynthetic efficiency in different plant species on various temperatures. And he also tries to filter out the phylogenetic signal from photosynthetic mechanisms. This paper is no different. Read it yourself!
Full citation: Galmes, J., Kapralov, M. V., Copolovici, L. O., Hermida-Carrera, C., & Niinemets, Ü. (2015). Temperature responses of the Rubisco maximum carboxylase activity across domains of life: phylogenetic signals, trade-offs, and importance for carbon gain. Photosynthesis Research, 123(2), 183-201. (link to full text)
Temperature response of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalytic properties directly determines the CO2 assimilation capacity of photosynthetic organisms as well as their survival in environments with different thermal conditions. Despite unquestionable importance of Rubisco, the comprehensive analysis summarizing temperature responses of Rubisco traits across lineages of carbon-fixing organisms is lacking. Here, we present a review of the temperature responses of Rubisco carboxylase specific activity (kccat) within and across domains of life. In particular, we consider the variability of temperature responses, and their ecological, physiological, and evolutionary controls. We observed over two-fold differences in the energy of activation (ΔH a) among different groups of photosynthetic organisms, and found significant differences between C3 plants from cool habitats, C3 plants from warm habitats and C4 plants. According to phylogenetically independent contrast analysis, ΔH a was not related to the species optimum growth temperature (T growth), but was positively correlated with Rubisco specificity factor (S c/o) across all organisms. However, when only land plants were analyzed, ΔH a was positively correlated with both T growth and S c/o, indicating different trends for these traits in plants versus unicellular aquatic organisms, such as algae and bacteria. The optimum temperature (T opt) for kccat correlated with S c/o for land plants and for all organisms pooled, but the effect of T growth on T opt was driven by species phylogeny. The overall phylogenetic signal was significant for all analyzed parameters, stressing the importance of considering the evolutionary framework and accounting for shared ancestry when deciphering relationships between Rubisco kinetic parameters. We argue that these findings have important implications for improving global photosynthesis models.