In vitro evaluation of dehydration tolerance in AtDREB1A transgenic potatoes

Abiotic stresses have negative effects on potato growth and production. To enhance the abiotic stress tolerance of the commercial potato cultivar, Desiree, rd29A::AtDREB1A transgenic lines have been developed. The salinity and freeze tolerance of these transgenic lines has previously been demonstrated; however, their dehydration tolerance remains to be elucidated. First of all, we have tackled the reproducible tolerance evaluation methodology, which have been the hurdle for selecting the stable dehydration tolerant phenotypes in potato. A novel in vitro method was developed using the rotary liquid culture combined with PEG. This method enhanced oxygen diffusion into the medium and diminished root damage/injury during plant transfer, thereby reducing the side effects caused by hypoxia and penetration of osmotica. In the present study, we evaluated the dehydration tolerance of twelve transgenic potato lines, and seven of the transgenic lines showed enhanced dehydration tolerance in comparison with the non-transgenic line. However, we observed growth retardation in some dehydration tolerant lines. Therefore, balance between the dehydration tolerance and growth retardation of the transgenic plants should be considered. Four of seven of the transgenic lines displayed enhanced dehydration tolerance without growth retardation, and may represent good candidates for practical application.