  Gene expression levels exhibit stochastic variations among genetically
identical organisms under the same environmental conditions (called gene
expression "noise" or phenotype "fluctuation"). In yeast and Escherichia coli,
positive correlations have been found between such gene expression noise and
"plasticity" with environmental variations. To determine the universality of
such correlations in both unicellular and multicellular organisms, we focused
on the relationships between gene expression "noise" and "plasticity" in
Arabidopsis thaliana, a multicellular model organism. In recent studies on
yeast and E. coli, only some gene groups with specific properties of promoter
architecture, average expression levels, and functions exhibited strong
noise-plasticity correlations. However, we found strong noise-plasticity
correlations for most gene groups in Arabidopsis; additionally, promoter
architecture, functional essentiality of genes, and circadian rhythm appeared
to have only a weak influence on the correlation strength. The differences in
the characteristics of noise-plasticity correlations may result from
three-dimensional chromosomal structures and/or circadian rhythm.
