An automated growth enclosure for metabolic labeling of Arabidopsis thaliana with (13)C-carbon dioxide - an in vivo labeling system for proteomics and metabolomics research

BACKGROUND: Labeling whole Arabidopsis (Arabidopsis thaliana) plants to high enrichment with (13)C for proteomics and metabolomics applications would facilitate experimental approaches not possible by conventional methods. Such a system would use the plant's native capacity for carbon fixation to ubiquitously incorporate (13)C from (13)CO(2 )gas. Because of the high cost of (13)CO(2 )it is critical that the design conserve the labeled gas. RESULTS: A fully enclosed automated plant growth enclosure has been designed and assembled where the system simultaneously monitors humidity, temperature, pressure and (13)CO(2 )concentration with continuous adjustment of humidity, pressure and (13)CO(2 )levels controlled by a computer running LabView software. The enclosure is mounted on a movable cart for mobility among growth environments. Arabidopsis was grown in the enclosure for up to 8 weeks and obtained on average >95 atom% enrichment for small metabolites, such as amino acids and >91 atom% for large metabolites, including proteins and peptides. CONCLUSION: The capability of this labeling system for isotope dilution experiments was demonstrated by evaluation of amino acid turnover using GC-MS as well as protein turnover using LC-MS/MS. Because this 'open source' Arabidopsis (13)C-labeling growth environment was built using readily available materials and software, it can be adapted easily to accommodate many different experimental designs.