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Stig Uggerhøj Andersen

Stig Uggerhøj Andersen

Associate professor


Identification and analysis of novel symbiotic mutants (with Niels Sandal)

To characterize the function of  a specific gene, it is important to have access to plant lines carrying a loss-of-function allele of the gene of interest. At the CARB centre, we are using the mobile element Lotus retrotransposon 1 (LORE1) to establish a large mutant population. We have annotated all the LORE1 insertions in this population using high-throughput Illumina sequencing, and we are now screening the population for aberrant symbiotic phenotypes. Once a mutant with an interesting phenotype has been identified, we can quickly identify the causal gene because of the well-characterized mutant population. The project is aimed at the identification and detailed characterization of novel symbiotic mutants to improve our understanding of symbiotic nitrogen fixation.

Natural variation in plant symbiotic and pathogen responses

Plants continuously interact with countless microorganisms of both pathogenic and symbiotic nature. Because the handling of these interactions is vital to the survival of the plant, there is a strong selective pressure on the genetic components regulating them. Based on a collection of Lotus japonicus ecotypes, we use association and QTL analysis to identify the genetic components responsible for the variation in plant-microorganism interactions in natural populations. The project involves bioinformatic data analysis and quantitative phenotyping based on image analysis.

Regulation of plant defense responses during symbiosis

To allow a symbiotic infection, microorganism invasion has to be coordinated with plant pathogen defense systems. So far, little is known about the mechanisms behind this cross-talk. Using the LORE1 resource, we are now establishing a collection of Lotus japonicus defense mutants. By investigating the effects of defense gene mutations on the symbiotic process, we can identify the primary defense signaling pathways influencing symbiosis.