| dc.description.abstract | Phenotypic plasticity is the ability of genetically identical organisms to produce
differing phenotypes in response to environmental heterogeneity. While there are two
central models for the genetic basis of phenotypic plasticity few studies have identified
the genetic and molecular basis of plasticity. I used three recombinant inbred lines
(RILs), of Arabidopsis thaliana generated by crossing two natural genotypes, and
obtaining progeny after recombination, for a global gene expression study. Of the three
RILs, one bolted (transition to reproductive tissue) later if the seeds experienced a coldstratification
period relative to the seeds that did not experience this cold-treatment
(sensitive-positive), one bolted earlier if the seeds experienced the cold-stratification
relative to the non-cold treated seeds (sensitive-negative), and one did not change when it
bolted regardless of the cold stratification of seeds (homeostatic). I found different sets of
genes differentially expressed in the three RILs suggesting that the response to the same
regime of cold-stratification is via different pathways. The homeostatic genotype
increased transcription of protein metabolism genes in response to cold stratification;
whereas the plastic genotypes differentially expressed genes involved in stress response.
This cold-stratification which is a common dormancy breaking cue for these plants may
also be perceived as a stress, as the plants differentially expressed stress genes. Thus both
gene expression and perception of environment may be involved in plastic responses to
environmental heterogeneity. | en |
