Metabolic profiling of in vitro micropropagated and conventionally greenhouse grown ginger (Zingiber officinale)

Ginger is an important medicinal and culinary herb, known worldwide for its health promoting properties. Because ginger does not reproduce by seed, but is clonally propagated via rhizome division and replanting, it is susceptible to accumulation and transmittance of pathogens from generation to generation. In addition, such propagation techniques lead to slow multiplication of particularly useful stocks. We have developed an in vitro propagation method to alleviate these problems. Metabolic profiling, using GC/MS and LC-ESI-MS, was used to determine if chemical differences existed between greenhouse grown or in vitro micropropagation derived plants. Three different ginger lines were analyzed. The constituent gingerols and gingerol-related compounds, other diarylheptanoids, and methyl ether derivatives of these compounds, as well as major mono- and sesquiterpenoids were identified. Principal component analysis and hierarchical cluster analysis revealed chemical differences between lines (yellow ginger vs. white ginger and blue ring ginger) and tissues (rhizome, root, leaf and shoot). However, this analysis indicated that no significant differences existed between growth treatments (conventional greenhouse grown vs. in vitro propagation derived plants). Further statistical analyses (ANOVA) confirmed these results. These findings suggest that the biochemical mechanisms used to produce the large array of compounds found in ginger are not affected by in vitro propagation.