The genes aroA and trnQ are located upstream of psbO in the chromosome of Synechocystis 6803.

We have identified the existence of two genes, trnQ and aroA, located upstream of the psbO gene in Synechocystis sp. PCC 6803. The trnQ gene encodes a glutamine-specific transfer RNA (tRNA(Gln)) and the sequence given is the first reported for any cyanobacterium. The gene seems to exist as a single copy since its deletion results in non-viable mutation. The aroA gene encodes for 5-enolpyruvylshikimate 3-phosphate synthase and its discovery in the genome of Synechocystis 6803 is the first genetic evidence for the existence of the shikimate biosynthetic pathway in cyanobacteria. Interestingly, the partial sequence shares close homologies with the sequences of aroA from Gram-positive bacteria.