Expression of , a Novel YSK-Type Dehydrin Gene from Bermudagrass, Responses to Drought Stress through the ABA-Dependent Signal Pathway.

Dehydrin improves plant resistance to many abiotic stresses. In this study, the expression profiles of a dehydrin gene, , were estimated under various stresses and abscisic acid (ABA) treatments in two bermudagrasses ( L.): Tifway (drought-tolerant) and C299 (drought-sensitive). The expression of was up-regulated by high temperatures, low temperatures, drought, salt and ABA. The sensitivity of to ABA and the expression of under drought conditions were higher in Tifway than in C299. A 1239-bp fragment, CdDHN4-P, the partial upstream sequence of the gene, was cloned by genomic walking from Tifway. Bioinformatic analysis showed that the CdDHN4-P sequence possessed features typical of a plant promoter and contained many typical elements, including a transcription initiation site, a TATA-box, an ABRE, an MBS, a MYC, an LTRE, a TATC-box and a GT1-motif. Transient expression in tobacco leaves demonstrated that the promoter CdDHN4-P can be activated by ABA, drought and cold. These results indicate that is regulated by an ABA-dependent signal pathway and that the high sensitivity of to ABA might be an important mechanism enhancing the drought tolerance of bermudagrass.