A novel wheat α-amylase inhibitor gene, TaHPS, significantly improves the salt and drought tolerance of transgenic Arabidopsis.

On the basis of microarray analyses of the salt-tolerant wheat mutant RH8706-49, a previously unreported salt-induced gene, designated as TaHPS [Triticum aestivum hypothetical (HPS)-like protein], was cloned. Real-time quantitative polymerase chain reaction analyses showed that expression of the gene was induced by abscisic acid, salt and drought. The encoded protein was found to be localized mainly in the plasma membranes. Transgenic Arabidopsis plants overexpressing TaHPS were more tolerant to salt and drought stresses than non-transgenic wild-type (WT) plants. Under salt stress, the root cells of the transgenic plants secreted more Na⁺ and guard cells took up more Ca²⁺ ions. Compared with wild-type plants, TaHPS-expressing transgenic plants showed significantly lower amylase activity and glucose and malic acid levels. Our results showed that the expression of TaHPS inhibited amylase activity, which subsequently led to a closure of stomatal apertures and thus improved plant tolerance to salt and drought.