Heterogeneous distribution of metabolites across plant species

Abstract

We investigate the distribution of flavonoids, a major category of plant secondary metabolites, across species. Flavonoids are known to show high species specificity, and were once considered as chemical markers for understanding adaptive evolution and characterization of living organisms. We investigate the distribution among species using bipartite networks, and find that two heterogeneous distributions are conserved among several families: the power-law distributions of the number of flavonoids in a species and the number of shared species of a particular flavonoid. In order to explain the possible origin of the heterogeneity, we propose a simple model with, essentially, a single parameter. As a result, we show that two respective powerlaw statistics emerge from simple evolutionary mechanisms based on a multiplicative process. These findings provide insights into the evolution of metabolite diversity and characterization of living organisms that defy genome sequence analysis for different reasons.

Testing the boundaries of closely related daisy taxa using metabolomic profiling

“…Many chemotaxonomic studies have targeted specific compounds (e.g., Zidorn & Stuppner, 2001;Kite & al., 2003Kite & al., , 2007Saito & al., 2009). One major benefit of this approach is the identification of biologically interesting compounds that may explain differences between taxa in their ecology and evolutionary history (Takemoto & Arita, 2009;Wink & al., 2010;Kang & al., 2011). By contrast, the untargeted approach we took in this study resulted in thousands of features and an extremely large dataset, making it impossible at this time to identify individual compounds and their ecological roles in Olearia (cf.…”

Current Understanding of the Formation and Adaptation of Metabolic Systems Based on Network Theory

“…In particular, the metabolite distributions of flavonoids, a type of secondary metabolite in plant species, are well investigated because of the great divergence of flavonoids. By analyzing this bipartite network, the following universal properties of flavonoid distribution were revealed despite different compositions of flavonoids among families [ 98 , 99 ]. (i) The number of flavonoids in a species and the number of plant species sharing a flavonoid follow a heterogeneous (power-law-like) distribution ( Figure 10 a).…”

“…Moreover, a possible origin of these structural properties was proposed [ 98 , 99 ], and these striking properties are reproduced through simple evolutionary processes: the emergence of new species due to mutations and the development of new flavonoids through modifications in the existing flavonoids.…”

Nested structure acquired through simple evolutionary process

“…We developed an evolving network model based on the model proposed by Takemoto and Arita (2009) to explain plant evolution. In our model, a small initial plant-animal mutualistic network ( Fig.…”

“…To estimate parameter q, we need to consider the time evolution of L. This is derived as L ≈ (1−p)t/(1−q) (Takemoto and Arita, 2009). Since A = (1−p)t, parameter q is estimated as…”