Comparative Analysis of the Wood Metabolites of Three Poplar Clones Using UPLC-Triple-TOF-MS

Poplar, a woody tree species, is widely used for industrial production and as a protective forest belt. Different clones of poplar exhibit clear variation in terms of morphological and physiological features, however, the impact of the genetic variation on the composition and abundance of wood metabolite have not been fully determined. In this study, ultra-high pressure liquid chromatography-triple time of flight-mass spectrometer (UPLC-Triple-TOF-MS) was used to explore the metabolite changes in poplar wood from three clones, including Populus deltoides CL. '55/65', P. deltoides CL. 'Danhong', and P. nigra CL. 'N179'. A total of 699 metabolites were identified. Clustering analysis and principal component analysis display that the metabolic differences of wood have allowed distinguishing different species of poplar. Meanwhile, eight significantly different metabolites were screened between P. deltoides and P. nigra, which may be considered as valuable markers for chemotaxonomy. In addition, the highly discriminant 352 metabolites were obtained among the three clones, and those may be closely related to the distinction in unique properties (e.g., growth, rigidity and tolerance) of the poplar wood cultivars. This study provides a foundation for further studies on wood metabolomics in poplar, and offers chemotaxonomic markers that will stimulate the early screening of potentially superior trees.