A transgenic approach to improve the drought tolerance of potato

摘要

South Africa is classified as a water-stressed country. All technologies, including biotechnological tools, should therefore be utilized to assist in the protection of crops against adverse environmental conditions. A project was initiated in 2012 tocreate a more drought tolerant local potato cultivar using a transgenic approach. The StMYBlR-1 transcription factor (TF) gene was isolated from potato cultivar 'BP1' and subcloned into a plant transformation vector under constitutive {CaMV 355) or inducible (rd29A) promoter control. Transgenic lines of potato 'BP1' with the different constructs were generated. The transgenic StMYBlR-1 gene was stably inserted into the potato genome. The highest expressing transgenic lines were selected with RT-qPCR, which also verified the inducible promoter behaviour under drought stress conditions. It is proposed that the transgenic TF gene will activate delayed response drought-protective genes and in turn render the potato plant more drought tolerant, since less water will be lost by the plant under water-stressed conditions. Relative water content (RWC%) results, visual appearance after 11 days of stress, and survival rates after the 15 d water-stress period of the first greenhouse trial, indicated that two transgenic potato lines, C3 and D6, performed better under drought conditions at 10 days without water (dwow) compared to 'BP1'. The RWC% results could not be confirmed in the second trial. None of the transgenic lines had statistically significantly higherbiomass yields than 'BP1' under drought stressed greenhouse conditions. It can therefore not be concluded that the insertion of the StMYBlR-1 transgene improved the drought tolerance of any of these transgenic potato lines, compared to the non-transformed plants.