The MAIN RESEARCH LINES leading up to my scientific profile are:
1. Effect of environmental conditions associated with Climate Change in the physiology and yield of plants As is shown in the point 2 of this document and the information described in the CV, an important part of my scientific career has focused on studying the capacity of the atmospheric N2 fixing and non-fixing plants to future environmental conditions (CO2, effect of drought, rising temperatures) detailed for the Mediterranean area by the Intergovernmental Panel on Climate Change (IPCC, 2007). Those studies have been conducted under controlled conditions (growth chambers and greenhouses), semi-controlled (temperature gradient greenhouses) and natural conditions (Free Air CO2 Exchange, FACE). In these studies I have proceeded to study the effect of Climate Change on yield and physiological characters responsible for the adaptation of plants to water shortage, high temperature in interaction with the elevated CO2. The results obtained so far indicate the effect of elevated CO2 on plants, regardless of being fast and slow growing plants, will be conditioned by their interaction with other environmental factors (temperature, water availability and nutrition of soil and so on. ). Despite the diversity of species analyzed, in most of them, it was found that the environmental effect on C and N management are the major drivers of the stimulating effect of CO2 on plant growth.
2. Response of photosynthetic metabolism and its interaction with the C "management" in cereals, forage plants and other crop species The research developed in recent years has focused on the study of the formation (photosynthesis), use (respiration) and translocation (to other organs) of photoassimilated by plants and its implication on their productivity under optimum growth conditions and stressful growth conditions. As it has been described above, the use of C and N isotopes has contributed to highlight the relevancy of C "management" and its implication in rubisco activity and finally on plant growth. Discrimination against the heavy stable isotopes during diffusion through the stomata, the enzymatic processes (determined by rubisco), translocation and respiration are responsible for the plants to acquire a specific composition of stable isotopes in different plant material and external sources and sinks. These different signatures may be used to distinguish among others, assimilation and management of C and N at a time, which can be of particular relevance to the development of plants and their final product and its interaction with the environment where they grow.
In those works I have applied an online labelling methodology with stable isotopes. For this purpose the clamp measurement of photosynthesis of an IRGA was connected to an isotope mass spectrometer (IRMS). The system has been used to supply to the leaves 13CO2 of a known isotopic composition and it was observed how the 13C was incorporated into the leaves during photosynthesis, how it is assimilated through different metabolic pathways and then respired through the spikes, leaves, stems, roots and nodules (in the case of forage plants). Our group has been pioneer in a new methodology for analysing the isotopic composition of respired CO2. The IRGA was coupled to a specially designed chamber that enabled the accumulation of CO2 respired by the leaves, ear, roots and nodules. Studies carried out in the OPTIWHEAT and AGL (2006-13541-C02-01) projects where we analyzed the effect of drought and nitrogen deficiency on cereal plants have found that unlike to what followed by classical growth methodology (which "assumes" that there is not C loss through respiration), plants invested a large part of the C assimilated in their respiration. 3. C and N Isotopes applied to plant fluxomics As described in the literature, the fluxomic is a discipline that aims at analyzing the flows that occur at the cellular and organ level. The labelling of plant with 15N and 13C as tracers and characterization of the distribution of labelled compounds into the different plant organs provides an information of great importance in studies determining the flow of C and N in plants. After supply of stable isotopes to cell cultures or organs (pulse), the isotopes are distributed through the network of cellular metabolic activities or organs. The interaction between the C and N metabolism can be studied further by analyzing the isotopic composition of 15N and 13C marked on each of the metabolites such as amino acids (especially glutamate, glutamine, aspartate, asparagine), sugars (especially glucose, fructose and sucrose) and organic acids (especially malate and citrate). The double labelling of carbon and nitrogen allows the characterization of compounds (sugars, amino acids, starch, etc.) which are treated and transported to different tissues. As mentioned above, this point is of particular importance in studies related to the increase of CO2, where the photosynthetic activity and consequently the production of plants is influenced by the C source/sink of C and N in different tissues. Besides the role of amino acids as a source of N, the labelling studies conducted by our group under conditions of drought stress revealed the fact that these substances might also play an important role as osmoregulant agents. Similarly to what described by other studies these results reveal that amino acids (proline, D-D-Pinitol or Ononitol, etc.) contribute to reduce the effect by stressing the protection of macromolecular structures and functions, and can thus serve as a form of metabolically compatible storage during periods of stress. In this sense, our group at the University of Barcelona has developed in the context of the current project OPTIWHEAT (along with the PERMED project) the methodology for the analysis of metabolites marked with N or C.
4. Proteomic two-dimensional characterization “Proteome" refers to all proteins encoded by the genome of an organism, and therefore "proteomics" may be understood as a comprehensive study of proteins by the proteome, including changes in structure and abundance in response to environmental and developmental conditions. Proteomics has emerged as an important topic in assessing the responsiveness of the plants. In this way, recent studies conducted by our group at the PERMED project where alfalfa plants where exposed to drought conditions, have detected 111 proteins affected by low water availability. Our study showed that drought adversely affected the proteins involved in carbon metabolism, amino acids synthesis, energy process, defence etc. This work highlights the fact that direct assessment of protein expression through the analysis of proteomics and the application of integrated methodological approaches are very advantageous for the identification of proteins involved in the responsiveness of seedlings grown in different environmental conditions. This information could be of great importance for understanding the ability of plant response to CO2 levels expected in the following decades, which may help in future breeding programs.