Technological and Physiological Aspects of GC-MS Based Metabolite Profiling for Plant Stress Responses

Comparative metabolomics contributes to an enhanced understanding of the salt and drought acclimation processes in legumes and other plant species. Metabolomic approaches specifically address the phenomena and potential function of complex metabolic acclimation patterns rather than focusing on single metabolite changes. The comparative metabolic phenotyping of related species from a common genus, in this case study, legumes of the Lotus family, provides new insights into the conservation or the diversity of metabolic responses. Using non-targeted GC-MS based metabolite profiling technology we compared the systems responses of selected model and forage species to non-lethal water limitation and elevated NaCl in the soil. A global reprogramming of metabolic pathways was observed for both the salt and the drought stress cues. Metabolic changes were gradual and progressive rather than stepwise transitions from non-stressed to stressed metabolic states. Our compendium of robust metabolome analyses revealed conserved metabolic responses to salt and to drought stress. Metabolic changes elicited by drought and salt acclimation were in part shared within each of the Lotus species, but only few of the common salt and drought responsive metabolites were also shared between all species. The implications of these results are discussed with regard to the current insights into legume water and salt stress physiology.