Transformation of Cichorium intybus with the HvBADH1 gene enhanced the salinity tolerance of the transformants

Drought, salinity, and freezing are three major abiotic stresses that adversely affect plant growth and crop yield. Previous reports have demonstrated that the overexpression of the betaine aldehyde dehydrogenase (BADH) gene can improve the tolerance of plants to osmotic and salinity stresses. In the present study, a novel and atypical BADH gene, HvBADH1, was transferred into Cichorium intybus by an Agrobacterium tumefaciens-mediated method. The integration and expression of HvBADH1 in the transformants were confirmed by PCR, Southern blot, and RT-PCR analysis. The stress tolerance traits of the transgenic plants were investigated by evaluating the phenotype of the transformed and wild-type (WT) plants, by measuring seven physiological indicators associated with stress resistance in plants, such as the K+ and Na+ contents, K+/Na+ ratio, malondialdehyde (MDA) content, chlorophyll content, the content of glycine betaine (GB), and relative conductivity in the leaves of the plants. The results revealed that the transgenic tissues had a better K+ retention ability, a reduced sensitivity to stress-induced hydroxyl radical production, an enhanced protection of the photosynthetic system, 4.92–6.95-fold greater amount of GB, and a higher growth rate compared with the WT plant. Accordingly, we concluded that the overexpression of HvBADH1 not only enhanced the salt tolerance of transgenic Cichorium intybus, but also reduced the cellular membrane damage caused by the salinity stress.