The photolyase gene from the plant pathogen Fusarium oxysporum f. sp. lycopersici is induced by visible light and alpha-tomatine from tomato plant

Abstract

Survival of irradiated spores from Fusarium oxysporum with ultraviolet radiation (UV) was increased following exposition to visible light, indicating that this phytopathogenic fungus has a mechanism of photoreactivation able to counteract the lethal effects of UV. A genomic sequence containing the complete photolyase gene (phr1) from F. oxysporum was isolated by heterologous hybridisation with the Neurospora crassa photolyase gene. The F. oxysporum phr1 cDNA was isolated and expressed in a photolyase deficient Escherichia coli strain. The complementation of the photoreactivation deficiency of this E. coli mutant by phr1 cDNA demonstrated that the photolyase gene from F. oxysporum encodes a functional protein. The F. oxysporum PHR1 protein has a domain characteristic of photolyases from fungi (Trichoderma harziaium, N. crassa, Magnaporthe grisea, Saccharomyces cerevisiae) to bacteria (E. coli), and clusters in the photolyases phylogenetic tree with fungal photolyases. The F. oxysporum phr1 gene was inducible by visible light. The phr1 expression was also detected in presence of alpha-tomatine, a glycoalkaloid from tomato damaging cell membranes, suggesting that phr1 is induced by this cellular stress.