Exploiting cryptic genetic variation to identify novel components of the KLUH-dependent growth pathway

• Applicant: Antoine Nicolas, Ph.D.
• Subject Area: Plant Genetics and Genomics
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 522967024

Plants are characterized by continuous growth throughout their lives, and mobile signals play a key role for controlling this growth. The cytochrome P450 KLUH/CYP78A5 promotes the maintenance of cell proliferation in a non-cell autonomous manner and contributes to the synthesis of a presumed novel growth signal in plants that has not yet been identified, despite intensive efforts. In this project I will used a novel approach based on cryptic genetic variation (CGV) to identify factors that interact with the KLUH-dependent growth pathway in order to provide novel leads for elucidating its function. For this purpose, the host lab generated kluh mutant lines in 48 different Arabidopsis thaliana accessions. Preliminary results on several accessions suggest that there is CGV amongst the chosen accessions that affects the strength of the kluh mutant phenotype and that can be used to identify factors that interact with the KLUH-dependent growth pathway. I exploit this CGV to achieve three objectives. First, I will describe the standing variation for the kluh mutant phenotype strength in the 48 different accessions of A. thaliana in detail. Based on these analyses pairs of accessions will be selected, with one accession per pair responding very strongly to the loss of KLUH function across all the traits, the other responding only weakly. Second, by using transcriptomics on these pairs of accessions I will identify molecular correlates to the phenotype strength in the different accession. Third, I will generate F2 populations by crossing kluh mutants from the pairs of accessions selected above and perform QTL analysis on these population to identify KLUH modifier loci. Taken together, these results will give data on CGV affecting the KLUH-dependent pathway and its molecular correlates and will permit us to identify novel components of the KLUH-dependent growth pathway.

• DFG Programme: WBP Position