Impact of various factors responsible for fluctuation in plant secondary metabolites

It is common perception that the content of secondary metabolites in pure lines of advanced generations of pedigree selections or intra-and inter-specific crosses should be stable like other qualitative and quantitative traits, but in fact this is usually not the case. In this review article, we try to give probable explanations on why the content of secondary metabolites fluctuates in subsequent generations of pure lines as well as advanced generations (F-7 onward) of intra-and inter-specific crosses. Genetic, ontogenic, morphogenetic and environmental factors are extremely important in the biosynthesis and accumulation of secondary metabolites. The biosynthesis of PSMs depend upon these various factors, change in only one factor may alter the content of PSMs though other factors remain constant. We here present a detailed view of the possible roles of the various factors in secondary metabolite instability. A good understanding of the mechanisms involved in secondary metabolite synthesis, degradation and accumulation in plants is required for the future formulation of strategies for the genetic improvement of secondary metabolite production in plants. (C) 2015 Elsevier GmbH. All rights reserved.