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.
| Original language | English |
|---|---|
| Pages (from-to) | 477-487 |
| Number of pages | 11 |
| Journal | Cell |
| Volume | 106 |
| Issue number | 4 |
| DOIs | |
| State | Published - 24 Aug 2001 |
Bibliographical note
Funding Information:We thank Jan Zeevaart (MSU, East Lansing) for measuring ABA contents and Marty Yanofsky, Joanne Chory, Nigel Crawford, and members of the Schroeder lab for comments on the manuscript. We thank Detlef Weigel for providing tagged seeds, Yoshiyuki Murata, Eugene Kim, Gethyn Allen, Naoyuki Kataoka, Alain Tissier, David Waner, Birgitt Klüsener, Nathalie Leonhardt, and Sébastien Thomine for discussions and advice, and Mathew Sharp and Rupal Shaw for assistance. This research was supported by NIH (R01GM60396-01), DOE (94ER201807), and NSF (MCB 0077791) grants (to J.I.S.) and an HFSP fellowship (J.M.K.).