Minisymposium 12: Genome evolution
Abs #
25001: A role for noncoding RNAs in ABA stress responses
Noncoding RNAs (ncRNAs) represent an emerging class of transcripts that lack significant open reading frames and encode RNA as their final product. Analyses of the AtGUT15 and AtCR20 genes of Arabidopsis, members of a noncoding RNA gene family, indicate that their physiological functions are associated with the plant ABA signaling network. These genes are devoid of phylogenetically conserved ORFs and possess a conserved secondary structure maintained during evolution by compensatory mutations. T-DNA insertion mutants for both genes (atgut15-1 and atcr20-1) and a homozygous double mutant line (gut15/cr20) show no obvious altered phenotype under normal growth conditions. However, the gut15/cr20 double mutant exhibits hypersensitivity to ABA under special conditions. Consistent with this, the double mutant is defective in several stress responses. Neither single mutation alone has a marked effect on plant development and growth at any tested condition. The implications of these findings are: 1) The AtGUT15 and AtCR20 gene family appears to be a necessary component of the early stage of development under specialized conditions. 2) AtGUT15 and AtCR20 share redundant functions, at least partially. 3) ncRNAs like GUT15 and CR20 can be used by plants as a modulator to interrelate stress and ABA signaling networks for controlling growth and development in response to the shifting environment. The connection between ABA signaling and RNA metabolism has emerged previously through the identification of several RNA-binding proteins genes, mutations of which cause ABA hypersensitivity. A very intriguing scenario would be that some ncRNAs, like GUT15 and CR20, interact with these RNA binding proteins and thereby modulate ABA signal transduction.
