The clock protein FREQUENCY (BcFRQ1) in Botrytis cinerea is required for normal mitochondrial function and has an extra-circadian role in nitrogen metabolism

A functional circadian clock was previously characterized in Botrytis cinerea and demonstrated the crucial role of BcFRQ, the ortholog of core clock component FREQUENCY from Neurospora crassa. It was previously shown that the corresponding knockout mutant Δbcfrq displayed an abnormal developmental phenotype (always-sclerotia) when grown on potato dextrose agar. In the present study, we demonstrate that this phenotype can be reversed back to macroconidia production by adding primary nitrogen sources, suggesting an extra-circadian role for BcFRQ in nitrogen metabolism. We performed an RNAseq study of wildtype and knockout mutant Δbcfrq under varying nutritional and light conditions, to identify the genes involved in 1) perturbed nitrogen metabolism in the mutant Δbcfrq and 2) additional extra-circadian functions of BcFRQ. Comparative gene expression profiling analysis of RNA-seq data for Botrytis cinerea strains (B05.10 and DeltaBcFRQ1) on CM media without nitrogen sources and complemented with Glutamine 0.1M as a primary source of Nitrogen. Samples were treated with constant light (LL), constant darkness (DD) or a light pulse (LP, 4 hours) and harvested at 48 hours.