Description
5-aminolevulinic acid (ALA) is the common precursor of all biological synthezised tetrapyrroles. Inhibition of ALA synthesis results in decreased amounts of chlorophylls, heme, siroheme and phytochrome. It was previously shown that 4 out of 5 Arabidopsis mutants uncoupling nuclear gene expression from the physiological state of the chloroplast are affected in plant tetrapyrrole biosynthesis. It is common to all four mutants to show a reduced ALA formation.