GintPDX1 encodes a protein involved in vitamin B6 biosynthesis that is up‐regulated by oxidative stress in the arbuscular mycorrhizal fungus Glomus intraradices

Abstract

Summary• Vitamin B6 is an essential metabolite that has recently been implicated in defense against cellular oxidative stress. In fungi, the de novo biosynthetic pathway of vitamin B6 involves two genes, PDX1 and PDX2. Here, we report a component of the PDX1/ PDX2 vitamin B6 biosynthetic pathway in an arbuscular mycorrhizal (AM) fungus.• Using rapid amplification of cDNA ends, we isolated the full-length cDNA of a PDX-like gene, GintPDX1, from Glomus intraradices. GintPDX1 expression was analysed by real-time reverse transcription-polymerase chain reaction (RT-PCR). GintPDX1 activity and function were investigated by heterologous complementation of the yeast strain Δsnz1, which is deficient in vitamin B6 biosynthesis.• Sequence data revealed that GintPDX1 is highly homologous to other identified PDX1 proteins. GintPDX1 restores prototrophy to the vitamin B6 auxotrophic yeast mutant and reverts its superoxide sensitivity. GintPDX1 is expressed throughout the fungal life cycle, with the highest transcription levels found in the intraradical fungal structures. GintPDX1 expression was induced in response to hydrogen peroxide, paraquat and copper.• The results demonstrate that AM fungi possess at least one component of the machinery necessary for vitamin B6 biosynthesis. Transcriptional regulation of GintPDX1 suggests a role for vitamin B6 as an antioxidant and modulator of reactive oxygen species in G. intraradices.

The antioxidative effect of de novo generated vitamin B6 in Plasmodium falciparum validated by protein interference

“…Additionally, it was shown that cercosporin-sensitive mutant strains can be rescued by complementation with the pdx1 gene of Phaseolus vulgaris [46]. Similar results were observed with a pdx1 (snz1)-deficient Saccharomyces cerevisiae strain which could be complemented with the pdx1 gene of the arbuscular mycorrhizal fungus Glomus intraradices (Gintpdx1) [47]. It has been shown that vitamin B 6 -deficient mutants of Arabidopsis thaliana are highly sensitive against high light and photo-oxidative stress due to the formation of 1 O 2 and the resulting severe lipid peroxidation [48].…”

GintAMT2, a new member of the ammonium transporter family in the arbuscular mycorrhizal fungus Glomus intraradices

“…The efficiency of the primer sets was evaluated by performing Real-Time PCR on several dilutions of DNA. The results obtained for the different treatments were standardized to the elongation factor 1-alpha (GintEF1a) gene levels (Benabdellah et al, 2009). Real Time RT-PCR determinations were performed on at least two independent biological samples from two replicate experiments.…”

“…A microsomal protein fraction of G. intraradices was extracted as previously described (Benabdellah et al, 2009). Briefly, extraradical mycelium of G. intraradices was homogenized with a pestle and mortar in a cold homogenization buffer (1:2, w/v) consisting of 25 mM Tris-HCl pH 7.5, 250 mM sucrose, 2 mM EDTA pH 8, 1 mM PMSF and 10% PVPP (w/v).…”

Arbuscular mycorrhizal fungal inoculation protects Miscanthus×giganteus against trace element toxicity in a highly metal-contaminated site

“…These proteins included Zn transporters, metallothioneins, heat shock protein (HSP) 90 and glutathione, which can be involved in the alleviation of ROS-induced damage (Hildebrandt et al, 2007). Finally, Benabdellah et al (2009) reported that GintGRX1, the first glomeromycotan dithiol glutaredoxin gene identified in an AM fungus, Rhizophagus irregularis (syn. Glomus intraradices), might play a role in protecting fungi against oxidative damage caused by trace elements.…”