MECHANISMS OF CROSS-TALK IN SECONDARY METABOLISM PATHWAYS IN ARABIDOPSIS REVEALED BY INTEGRATIVE FUNCTIONAL GENOMICS

Abstract

Phenylpropanoids play a critical role in plant defense against biotic and abiotic stresses. To understand the properties of the phenylpropanoid metabolic network and its association with other such networks, we perturbed the flavonoid sub-network using a bacterial oxidoreductase gene, QuoA, and studied the perturbational responses at system levels. Results here suggest that phenolamide pathway plays a major role in channeling of metabolic intermediates to the lignin pathway in the perturbed QuoA lines. This is the first report showing an approach that leads to simultaneous accumulation of both lignins and anthocyanins at metabolite levels. Gene-metabolite relationships at the branch points in the network were found to control the branch pathways. Crosstalk between phenylpropanoid and other distant networks was discovered and their common regulatory mechanisms identified, which overlapped with stress response pathways. Overall, this study has demonstrated the utility of genetic perturbations to reveal novel properties of secondary metabolism network.