Investigation of the response to salinity of transgenic potato plants overexpressing the transcription factor StERF94

ABSTRACT

Salinity is one of the most important constraints threatening the cultivation of potato plants (Solanum tuberosum L.). Itaffects plant growth and leads to significant yield loss. Consequently, it is important to improve the tolerance of potatoplants to salinity. In this context, we investigated the involvement of a potato ethylene responsive factor (StERF94) in plantresponse to salinity, since our previous genome-wide analysis showed that it may be related to biotic and abiotic stressresponse. ERF proteins belong to a large family of transcription factors that participate in plant response to abiotic stresses.We have previously identified the StERF94 gene which shows increased expression in potato plants submitted to salttreatment. In this study, transgenic potato plants overexpressing StERF94 were produced and submitted to salt treatment(100 mM NaCl) in vitro and under greenhouse culture conditions. StERF94 transgenic lines showed lower decrease of stemelongation under salt treatment in comparison to non-transgenic wild-type plants. Moreover, these plants showed a lowlevel of H2O2 and Malondialdehyde content, and an increase in catalase and GPX (Gluthation peroxidase) activitiescompared to non-transgenic plants. In a second step, enhanced expression of some target genes for example CuZn-SOD,DHN25 (Dehydrin) and ERD (Early Responsive to Dehydration) was noted in the StERF94 transgenic plants, submitted tosalt treatment. The StERF94 factor was also involved in the activation of osmoprotectant synthesis. Taken together, all thesedata suggest that overexpression of the StERF94 transcription factor increases the tolerance of potato plants to salinity byimproving plant growth, osmoprotectant synthesis and antioxidant activityleading to low oxidative stress damage.