Fig. 8

Contrasting transcriptional responses of core components of ABA signaling to exogenous ABA or osmotic stress-derived endogenous ABA between maize roots and leaves. The expression patterns of core ABA signaling components genes are illustrated based on real-time PCR results. The transcripts of ZmPYLs homologous to monomeric- and dimeric-type Arabidopsis ABA receptors were up- and down regulated by ABA or polyethylene glycol (PEG) in maize roots, respectively. This expression trend was reversed in leaves in the presence of ABA or dehydration. The transcripts of PP2Cs and SnRK2s were increased by ABA or osmotic stress in roots; in maize leaves, they were induced or maintained at constant levels, depending on the isoform within each family. Differences in core signaling components in the presence of exogenous ABA versus stress-induced endogenous ABA were observed in leaves and roots