Author(s): Hugouvieux V, Kwak JM, Schroeder JI
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Abstract The plant hormone abscisic acid (ABA) regulates important stress and developmental responses. We have isolated a recessive ABA hypersensitive mutant, abh1, that shows hormone specificity to ABA. ABH1 encodes the Arabidopsis homolog of a nuclear mRNA cap binding protein and functions in a heterodimeric complex to bind the mRNA cap structure. DNA chip analyses show that only a few transcripts are down-regulated in abh1, several of which are implicated in ABA signaling. Consistent with these results, abh1 plants show ABA-hypersensitive stomatal closing and reduced wilting during drought. Interestingly, ABA-hypersensitive cytosolic calcium increases in abh1 guard cells demonstrate amplification of early ABA signaling. Thus, ABH1 represents a modulator of ABA signaling proposed to function by transcript alteration of early ABA signaling elements.
This article was published in Cell
and referenced in Journal of Biodiversity, Bioprospecting and Development