Isolation and heterologous expression of a gene encoding 4-hydroxyphenylpyruvate dioxygenase from the wheat leaf-spot pathogen, Mycosphaerella graminicola.

We describe the isolation and sequence of a gene encoding 4-hydroxyphenylpyruvate dioxygenase (HPPD) (EC 1.13.11.27)) from the wheat leaf-spot fungal pathogen Mycosphaerella graminicola (Septoria tritici), that directs the synthesis of 2,5-dihydroxyphenylacetate (homogentisic acid, HGA). The sequence of the deduced peptide showed homology to HPPDs from other organisms; the greatest identity was to a T-cell reactive protein, also identified as HPPD, from the human fungal pathogen Coccidioides immitis. As observed for HPPD from other sources, expression of the M. graminicola HPPD gene in Escherichia coli cells could be detected by the gradual development of a brown pigment in cultures as a result of the spontaneous oxidation and polymerisation of HGA. Pigment development in these cultures was prevented by the HPPD inhibitor sulcotrione.