A systems approach uncovers restrictions for signal interactions regulating genome-wide responses to nutritional cues in Arabidopsis.
As sessile organisms, plants must cope with multiple and combined variations of signals in their environment. However, very few reports have studied the genome-wide effects of systematic signal combinations on gene expression. Here, we evaluate a high level of signal integration, by modeling genome-wide expression patterns under a factorial combination of carbon (C), light (L), and nitrogen (N) as binary factors in two organs (O), roots and leaves. Signal management is different between C, N, and L and in shoots and roots. For example, L is the major factor controlling gene expression in leaves. However, in roots there is no obvious prominent signal, and signal interaction is stronger. The major signal interaction events detected genome wide in Arabidopsis roots are deciphered and summarized in a comprehensive conceptual model. Surprisingly, global analysis of gene expression in response to C, N, L, and O revealed that the number of genes controlled by a signal is proportional to the magnitude of the gene expression changes elicited by the signal. These results uncovered a strong constraining structure in plant cell signaling pathways, which prompted us to propose the existence of a "code" of signal integration.
Krouk
Gabriel
G
Center for Genomics & Systems Biology, New York University, Department of Biology, New York, New York, United States of America.
Tranchina
Daniel
D
Lejay
Laurence
L
Cruikshank
Alexis A
AA
Shasha
Dennis
D
Coruzzi
Gloria M
GM
Gutiérrez
Rodrigo A
RA
D000222:Adaptation, Physiological / Q000502:physiology; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D003198:Computer Simulation; D003463:Cues; D005786:Gene Expression Regulation / Q000502:physiology*; D008954:Models, Biological; D018515:Plant Leaves / Q000502:physiology*; D018517:Plant Roots / Q000502:physiology*; D020543:Proteome / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
D029681:Arabidopsis Proteins; D020543:Proteome