Alejandre-Durán Encarna, Roldán-Arjona Teresa, Ariza Rafael R, Ruiz-Rubio Manuel
Departamento de Genética, Facultad de Ciencias, Edificio Gregor Mendel, Campus Rabanales, Universidad de Córdoba, 14071 Córdoba, Spain.
Fungal Genet Biol. 2003 Nov;40(2):159-65. doi: 10.1016/s1087-1845(03)00089-6.
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.
尖孢镰刀菌经紫外线（UV）照射后的孢子在暴露于可见光后存活率增加，这表明这种植物病原真菌具有一种光复活机制，能够抵消紫外线的致死效应。通过与粗糙脉孢菌光裂合酶基因进行异源杂交，分离出了包含尖孢镰刀菌完整光裂合酶基因（phr1）的基因组序列。分离出尖孢镰刀菌phr1 cDNA并在光裂合酶缺陷型大肠杆菌菌株中表达。phr1 cDNA对该大肠杆菌突变体光复活缺陷的互补作用表明，尖孢镰刀菌的光裂合酶基因编码一种功能性蛋白质。尖孢镰刀菌PHR1蛋白具有从真菌（哈茨木霉、粗糙脉孢菌、稻瘟病菌、酿酒酵母）到细菌（大肠杆菌）的光裂合酶的特征结构域，并在光裂合酶系统发育树中与真菌光裂合酶聚类。尖孢镰刀菌phr1基因可被可见光诱导。在存在α-番茄碱（一种来自番茄的破坏细胞膜的糖生物碱）的情况下也检测到了phr1表达，这表明phr1是由这种细胞应激诱导的。
