Overexpression of dehydration-responsive element-binding 1 protein (DREB1) in transgenic Solanum tuberosum enhances tolerance to biotic stress

Abstract

Plant growth and productivity are greatly affected by environmental stresses such as dehydration, high salinity, low temperature and pathogen infection. Plant adaptation to these environmental stresses is controlled by cascades of molecular networks. The dehydration-responsive element-binding (DREB) transcription factors play an important role in the response of plants to environmental stresses by controlling the expression of many stress-related genes. They specifically interact with C-repeat/DRE (A/GCCGAC) sequences present in the promoter regions of target genes. One of the DREB1 cDNA was previously cloned and overexpressed in transgenic potato plants. These transgenic plants displayed an improved tolerance to high salinity and drought stresses. The StDREB1 factor belongs to A-4 group that seem to be involved in biotic stress response. This report investigates the effect of Fusarium solani infection on the StDREB1 transgenic lines. Since a number of pathogenesis-related (PR) proteins are considered as DREB1 target genes, the expression of PR2, PR9 and PR3 genes were tested under biotic stress conditions. The β-1,3-glucanase (PR2) was specifically induced upon infection, whereas the chitinase and the peroxydase were expressed constitutively. The data also show that high levels of DREB1 transcripts accumulated rapidly when wild-type and transgenic plants were infected by F. solani. DREB1 transgenic potato plants accumulated higher levels of pathogenesis-related gene transcripts, such as PR2. These results showed that StDREB1 plays an important role in response to fungal attack in potato.