Adám Attila L, Kohut Gábor, Hornok László
Agricultural Biotechnology Center, Mycology Group of the Hungarian Academy of Sciences, Institute of Plant Protection, Szent István University H-2103 Gödöllo, Páter K. u.1, Hungary.
J Basic Microbiol. 2008 Jun;48(3):151-9. doi: 10.1002/jobm.200700403.
Delta Fphog1 mutants of Fusarium proliferatum obtained by targeted gene disruption of Fphog1, an orthologue of the Saccharomyces cerevisiae hog1 MAPK gene showed increased sensitivity towards different abiotic stressors including UV-irradiation, heat, salt, osmotic and hydrogen peroxide treatments. Incubation of the Delta Fphog1 mutants under hyperosmotic conditions was accompanied with prolonged growth arrest, inhibition of conidial germination, morphological abnormalities and time-dependent increase of the cell death rate. The wild type Fphog1 gene, under the control of its own promoter, was able to rescue the multistress sensitivity of the mutant strain. Real time qPCR data demonstrated that under salt and sorbitol stress conditions the Fphog1 gene is not subject of transcriptional regulation. Levels of reactive oxygen species (ROS), mitochondrial membrane permeability transition, nuclear disintegration and DNA fragmentation, indicators of programmed cell death (PCD) all showed significant increases under osmotic stress conditions in the Delta Fphog1 mutant in comparison to the wild type strain. These results suggest that an important function of Fphog1 is attenuating apoptotic phenotypes under salt and sorbitol stressors.
通过对酿酒酵母hog1 MAPK基因的直系同源基因Fphog1进行靶向基因破坏获得的层出镰刀菌Delta Fphog1突变体，对包括紫外线照射、热、盐、渗透和过氧化氢处理在内的不同非生物胁迫因子表现出更高的敏感性。在高渗条件下培养Delta Fphog1突变体伴随着生长停滞延长、分生孢子萌发抑制、形态异常以及细胞死亡率随时间的增加。野生型Fphog1基因在其自身启动子的控制下，能够挽救突变菌株的多重胁迫敏感性。实时定量PCR数据表明，在盐和山梨醇胁迫条件下，Fphog1基因不受转录调控。与野生型菌株相比，Delta Fphog1突变体在渗透胁迫条件下，活性氧（ROS）水平、线粒体膜通透性转换、核解体和DNA片段化（程序性细胞死亡（PCD）的指标）均显著增加。这些结果表明，Fphog1的一个重要功能是在盐和山梨醇胁迫下减弱凋亡表型。
