Abstract

The cultivated potato (Solanum tuberosum) is sensitive to freezing and drought stress, limiting their distribution and productivity. This research aimed to study drought and frost responses in non-transgenic (WT) and transgenic potatoes (Lines-Z45), genetically transformed with ScCBF1gene cloned from Solanum commersonii, a wild potato highly tolerant to abiotic stress. S. tuberosum cv Cardinal and S. commersonii DunPI243503 clone13 were genetically modified with 35Sp::ScCBF1gene. Freezing tolerance was studied by ion-leakage test in non-acclimated and cold-acclimated plants. Experimental design was a randomized complete block with three replications per experiment. Three independent experiments were performed in time. In S. commersonii, the comparative analysis of frost tolerance showed that Lines-Z45, significantly improved their frost tolerance. Moreover, the results showed that lines-Z45 improved frost tolerance after cold-acclimation. In relation to S. tuberosum, Lines-Z45 significantly improved frost tolerance compared with their WT. However, no significant differences were observed between cold-acclimated and non-acclimated plants. The same transgenic lines-Z45 were evaluated for drought tolerance both in Vitro and greenhouse conditions. For each genotype and drought treatment, three independent experiments were conducted using three replicates per experiment. In Vitro, different drought stress levels were induced by using PEG4000. Simulated drought stress in Vitro adversely affected plant growth in potato plantlets. Lines-Z45 in both Solanum species showed higher vegetative growth and plant survival. Also, Lines-Z45 showed significant best root development according to WinRhizo Pro-software. Greenhouse results, supported in Vitro testing, decreasing of stomatal conductance and photosynthetic parameters occurred in all genotypes during drought stress, WT were more adversely affected than Lines-Z45. QT-PCR analysis showed that ScCBF1 expression was associated with D1-Pyrroline-5-carboxylatesynthase gene expression and free proline synthesis in stems and leaves under stress. ScCBF1 gene was able to induce cold and drought tolerance, however the gain in drought tolerance was most relevant than freezing tolerance, in terms of agriculture needs. Acknowledgements, this research was carried out with financial support from FONDECYT (FI11075021) and MINAGRI (501364-70)