Abstract
Introduction - Hydroponics has been shown as a possible way to produce high quality plant biomass with improved phytochemical levels. Nevertheless, effects of plant biotic and abiotic environment can lead to drastic changes and plant growth conditions must be optimised. Objective - To evaluate how much microbes and Agrobacterium rhizogenes TR7 wild strain may affect the tropane alkaloid profile in Datura innoxia Mill. plants cultivated in hydroponic conditions. Methodology - Datura innoxia Mill. plants were cultivated in hydroponic with sterile or non-sterile conditions. For half of the non-sterile plants, Agrobacterium rhizogenes TR7 strain was added to the nutrient solution for hydroponics. The tropane alkaloid content of leaves and roots was analysed by UFLC/ESI-HRMS and MS/MS. The metabolite profiles were compared using partial least square-discriminant analysis. Results - In sterile conditions, aerial parts contained more scopolamine than the roots. However, the diversity of tropane alkaloids was greater in roots. Furthermore, 21 known compounds and four non-elucidated tropane alkaloids were found. The tropane alkaloid profile was shown to be statistically different between sterile and non-sterile hydroponic conditions. The levels of 3-acetoxy-6-hydroxytropane and 3'-hydroxylittorine were higher in plants inoculated with A. rhizogenes. Five other tropane compounds were found in higher amounts in non-axenic control plants. Hyoscyamine and scopolamine total contents were much higher in the whole plant co-cultivated with A. rhizogenes TR7 than in controls. Furthermore, the leaves and roots of axenic plants contained more alkaloids than non-sterile ones. Conclusion - In hydroponic conditions, microbes induced variations of the phytochemical levels. Addition of A. rhizogenes TR7 into the nutrient solutions improved the total hyoscyamine and scopolamine production.