Description
The Clade A PP2C Highly ABA-Induced1 (HAI1, At5g59220) is strongly up-regulated by low water potential in an ABA-dependent manner. Using knockout mutants of hai1, we found that HAI1 functions as a negative regulator of low water potential-induced proline and osmoregulatory solute accumulation. We also found a relatively weak and limited interaction of HAI1 with the RCAR/PYL family of ABA receptors. This, plus its induced expression, suggest that HAI1 remains active during stress and attenuates specific aspects of drought response.