Tom Theeuwen
Laboratory of Genetics at Wageningen University and Research, The Netherlands
In February 2023 I will defend my PhD thesis and continue as a Postdoc in the Laboratory of Genetics at Wageningen University and Research. In my work I use high-throughput phenotyping in dynamic environmental conditions to reveal potentially relevant physiological properties, and use genetics to reveal the underlying mechanisms. Doing this I hope to reveal how photosynthetic variation manifests itself in nature, and how it can be used to improve photosynthesis in crops.
Title: Exploring the unexplored: Unravelling the cyto-nuclear interactions in Arabidopsis thaliana to improve photosynthesis
Webinar date: Tuesday 4th April 14.00 CEST
Abstract: Natural genetic variation for photosynthetic traits is rapidly gaining more attention as a potential resource to improve plant performance. In these efforts the impact of variation in chloroplast and mitochondrial genomes are largely ignored due to the difficulty in separating their effect from nuclear-derived variation. Using haploid-inducer lines we developed an efficient system to generate new organelle-nuclear combinations, with the resulting genotypes referred to as cybrids. A large cybrid panel representing species wide organelle variation in Arabidopsis thaliana reveals variation for a large range of chlorophyll fluorescence-derived photosynthetic traits. Organellar genomes can result in phenotypic differences, regardless of the nuclear genome (i.e. additivity), as well as differences depending on the nuclear genome (i.e epistasis). One of the discoveries we made using our panel how natural variation for the NDH complex can result in increased photosynthetic performance. In addition, cybrids allow us to assess the extent of nuclear adaptation to naturally occurring organelle mutants. To reveal these nuclear adaptations a large doubled-haploid population, which is a cross between (just) two genotypes, was produced. Phenotyping this population in highly dynamic environments revealed a dozen QTLs connected to different photosynthetic mechanisms. All together it shows that there is ample room for improvement of photosynthetic traits, not only in the nuclear genome but also hidden in the organellar genomes. Moreover, we show that it is essential to phenotype plants in highly dynamic environmental conditions to reveal the full spectrum of natural genetic variation for photosynthetic performance.