Abstract:To explore the effects of DELLA protein deficiency on drought tolerance in Arabidopsis, we treated DELLA proteins deficient mutant della by drought stress. The survival rate, germination rate, water loss rate, and contents of proline, soluble sugar, and malondialdehyde were measured. Meanwhile, the gene expression patterns of the late embryogenesis abundant protein coding genes LEAs, which play important roles in dehydration protection of plant cell, and ABA responsive genes, such as LOX3, COR15b, and COR413, were investigated by qPCR. The results showed that: (1) after 21 days of drought stress and rewatering treatment, the survival rate of della mutant was significantly higher than that of wild type Ler; (2) the germination rate of della mutant was markedly higher than that of Ler on 1/2 MS with mannitol; (3) the water loss speed of leaves detached from della mutant was distinctly slower than that of Ler; (4) the contents of proline, soluble sugar, and malondialdehyde in della mutant were lower than that of Ler; (5) the upregulated expression of LEA genes in della mutant was higher than that of Ler, while the upregulated expression of ABA responsive genes was lower. These results suggest that the deficiency of DELLA proteins improves the drought resistance in Arabidopsis.