Overexpression of the VaERD15 gene increases cold tolerance in transgenic grapevine

Abstract

In plants, the Early Responsive to Dehydration (ERD) genes are rapidly activated in response to drought and other abiotic stresses. Here, we characterize the VaERD15 gene from the cold-resistant grapevine Vitis amurensis accession 'Shuangyou', and its counterpart VvERD15 from the cold-sensitive V. vinifera cultivar 'Red Globe'. To evaluate a role for VaERD15 in promoting cold tolerance, we expressed the VaERD15 in transgenic V. vinifera 'Red Globe' and evaluated its influence on type and cold stress-related physiological and biochemical indices. We also assessed the response of the ERD15 promoter and its deletion fragments from 'Shuangyou' and 'Red Globe' to low temperature, ABA, SA and PEG. Additionally, several proteins interacting with VaERD15 were identified and the expression profiles for the respective genes were evaluated in response to low temperature. We found that the VaERD15 protein contains a PAM2 domain and localizes in the nucleus and cell membrane. Under low-temperature stress, the expression of ERD15 in 'Shuangyou' was greater than that in 'Red Globe’. Transgenic 35S::VaERD15 plants showed greater cold tolerance and had lower electrical conductivity and malondialdehyde content than non-transgenic controls, while the contents of proline, soluble sugar, soluble protein and the activities of SOD, POD and CAT were higher than those in non-transgenic controls. The ERD15 promoter and its deletions could respond to low temperature, ABA, SA and PEG, but the degree of response to the treatments varied. Proteins interacting with VaERD15 were identified as xyloglucan endotransglucosylase/hydrolase protein 7, glutamine synthetase, 40S ribosomal protein 23 and disulfide-isomerase LQY1, and the corresponding genes responded to cold temperatures to varying degrees.