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Fig. 2 | BMC Biology

Fig. 2

From: A polyketide synthase from Verticillium dahliae modulates melanin biosynthesis and hyphal growth to promote virulence

Fig. 2

Verticillium dahliae VdPKS9 is not involved in quinone and oxidative stress responses. A Subcellular localization of VdPKS9 in V. dahliae. The VdPKS9-GFP fusion was introduced into the genome of wild-type strain AT13, and the transformant was incubated on hydrophobic coverslips for 24 h. The expression of the VdPKS9-GFP fusion in hyphae and conidia was observed by fluorescence microscope. Scale bar = 20 μm. B Sequence alignment of VdPKS9 with human quinone oxidoreductase PIG3 isoform 1. Aligned sequence with the dashed box in purple and blue color represents the alcohol dehydrogenase GroES-like domain and zinc-binding dehydrogenase domain, respectively. Genebank accession of PIG3: NP_671713. C Diagram depicting states of quinone transformation in mammals and plants. One-electron transfer of quinone reduction produces a stable free radical anion intermediate: semiquinone. Two-electron reduction of quinone by NAD(P)H-dependent quinone-reducing enzymes yields hydroxyquinone which can also be excreted or oxidized to the semiquinone. In this cycle, the hydroxyquinone and semiquinone states oxidized by molecular oxygen to form superoxide anions that maintain ROS generation [73]. D, F Colony morphology of V. dahliae strains growth on medium supplemented with quinones and oxidative compounds. Wild-type strain AT13 (WT), VdPKS9 deletion strains (ΔVdPKS9), and corresponding ectopic transformants (ECΔVdPKS9) were cultured on Czapek medium that supplemented with quinones (125 and 250 μM 1,2-naphthoquinone and 1,4-benzoquinone, as well as 10 and 30 μM 9,10-phenanthrenedione and menadione) and hydrogen peroxide (H2O2). The phenotypes were photographed 7 days after incubation at 25 °C. D Medium supplemented with quinones compounds. F Medium supplemented with H2O2. Error bars represent standard errors of at least 3 independent repeated measurements, and each experiment was replicated three times. *P < 0.05 (one-way ANOVA). E Medium supplemented with quinone compounds

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