Lisa Koch (Friedrich-Alexander-Universität Erlangen-Nürnberg, FAU)
Lisa Koch is operating the photosynthesis measuring device. Photo: Franziska Eidloth
Lisa Koch's Master thesis was awarded with the Prize for the Best Plant Science Master Thesis, which was carried out at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) in the year 2022
Title: Influence of elevated temperature in combination with different nitrogen concentrations on the growth and development of potato plants
Overexpression of the tuberigen StSP6A in combination with high nitrogen feeding regimes is able to overcome the inhibiting properties of high nitrogen treatment and heat on the tuberization process and therefore increase yield under otherwise inhibiting conditions.
The combinatory effects of elevated temperature and nitrogenous fertilizer on the development and yield of potato plants (Solanum tuberosum L.) have not been described yet. Research on this topic is of great importance as climate change and a growing world population result in an endangered food stability. Potato belongs to the most important staple crops worldwide. Potato plants are susceptible to elevated ambient temperature resulting in a reduced yield.
Nitrogen (N) is an essential factor for plant growth and development and large amounts of nitrogenous fertilizers are applied in agriculture to enhance yield of various plants. There are many efforts to increase nitrogen use efficiency in order to reduce the negative impact on the environment by massive usage of fertilizers. In addition, growth of potato plants is favored by nitrogen; however, tuberization is inhibited by high N fertilization.
In this thesis, the effects of deficient/ excess N in combination with heat on potato plant growth and tuber development were investigated. Low N resulted in small plants with an early onset of tuberization and leaf senescence. These processes were either delayed or enhanced by heat, respectively. Both plant and tuber development were hampered by low N as compared to plants grown with medium (optimal) N supply.
High N resulted in big bushy plants while tuberization was strongly delayed which resulted in a shift in the source-sink-balance towards green biomass at the expense of tuber yield. Yield was highest in plants grown with medium N concentration under control conditions. However, these plants exhibited the strongest heat mediated yield reduction.
Under elevated temperature the yield did not significantly differ between different N regimes. This showed that N fertilization might have no positive effect on yield under heat, which is problematic from a climate change point of view.
The inhibition of tuberization through high N was overcome in transgenic plants that overexpressed StSP6A, a key tuberization gene, under control of the StLS1 promoter (active in green tissues). Instead of decreased yield under high N availability, the transgenicity resulted in even higher yield than under medium N supply. This was also true under elevated temperatures, where highly fertilized plants performed best. This suggests that a combination of StSP6A overexpression and high N seems to be a good possibility to ensure a stable potato yield under elevated temperature.
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Lisa Koch conducted this work at the Department of Biochemistry in the group of PD Dr. Sophia Sonnewald.