Salt and Drought Stress Tolerances in Transgenic Potatoes and Wild Species

Transgenic potatoes were employed to test whether a diverse range of gene actions can induce different stress tolerance(s). To select available transgenic lines, we measured growth profiles under non-stress conditions in our evaluation of transgenic lines and confirmed productivity under stress(es). We performed microarray analyses to clarify the abiotic stress tolerance mechanism controlled by AtDREB1A. Two transgenic lines out of over 200 independent genotypes displayed stable tuber production under high salinity stress conditions. We identified five significant genes that were induced by abiotic stress with AtDREB1A in potato; the reported homologs in Arabidopsis are downstream of the AtDREB1A gene. Our results suggest that the AtDREB1A gene acts as a transcriptional factor against abiotic stresses in potato, and that potato may have mechanisms in abiotic stress tolerance(s) controlled by a native transcriptional factor similar to AtDREB1A. Besides uses of the exotic genes which can enhance abiotic stress tolerance, exploitation of the native genes in cultivated potatoes is also valuable for elucidating the basic knowledge and for orienting towards uses in crop improvement. Further challenges would be comparing the stress responses between cultivated potatoes and wild species in more detail, in order to examine (1) whether alternative tolerance mechanisms are possible, and (2) if so, whether effective germplasm enhancement could be carried out based on wild species to improve drought and salt stress tolerance of cultivated potato.