Metabolite profiling of leaves of three Epilobium species

BACKGROUND: The ability of plants to adapt to oxygen deficiency is associated with the presence of various adaptations, many of which are mediated by significant changes of metabolism. These changes allow resistant wetland plants to grow even in oxygen-deficient environment. 
AIM: The aim of the study was to carry out metabolic profiling of the leaves of the wetland species Epilobium palustre and Epilobium hirsutum, and the mesophyte species Epilobium angustifolium in order to identify the most characteristic metabolome traits of hypoxia-resistant plants. 
MATERIALS AND METHODS: Metabolite profiling was performed by GC-MS. Statistical analysis of metabolomics data was processed using R 4.2.1 Funny-Looking Kid. 
RESULTS: The resulting profile included about 360 compounds. 70 of these were identified and 50 compounds were determined to a class. Sugars (64) were the most widely represented in the obtained profiles. 16 amino and 20 carboxylic acids, lipids and secondary compounds have been identified. Significant differences were revealed between the profiles of leaf metabolomes of mesophyte E. angustifolium and hydrophytes E. hirsutum and E. palustre. The mesophyte was characterized by high levels of sugars. The metabolomes of wetland Epilobium species practically did not differ from each other and were characterized by the accumulation of amino acids, including GABA shunt intermediates, dicarboxylic acids of the Krebs cycle, and metabolites of glycolysis and lactic acid fermentation, which reflects the stimulation of anaerobic respiration, nitrogen metabolism, and alternative pathways of NAD(P)H reoxidation in wetland plants. 
CONCLUSIONS: Traits of metabolic profiles detected in hydrophyte Epilobium species can be used to assess the degree of plant resistance to oxygen deficiency.