A physiological role for oxalic acid biosynthesis in the wood-rotting basidiomycete Fomitopsis palustris

Abstract

A metabolic mechanism for oxalic acid biosynthesis in the woodrotting basidiomycete Fomitopsis palustris has been proposed on the basis of biochemical analyses of glucose metabolism. There was a strong correlation between glucose consumption and oxalate production. Oxalic acid was found to accumulate in the culture fluid in about 80% of the theoretical yield or about 5-fold, on the basis of the fungal biomass harvested. The results clearly indicate that glucose was not completely oxidized to CO2 by the tricarboxylic acid (TCA) cycle but converted mainly to oxalate. The determination of the 12 enzymes concerned has revealed the occurrence of the unprecedented metabolic coupling of the TCA and glyoxylate cycles that support oxalate biosynthesis. In this metabolic system, isocitrate lyase (EC 4.1.3.1), together with oxaloacetase (EC 3.7.1.1), was found to play a pivotal role in yielding oxalate from oxaloacetate via the acetate-recycling routes. Moreover, malate dehydrogenase (EC 1.1.1.37), with an extraordinarily high activity among the enzymes tested, was shown to play an important role in generating NADH by oxidation of malate to oxaloacetate. Thus, it is proposed that the wood-rotting basidiomycete acquires biochemical energy by oxidizing glucose to oxalate.

Involvement of FpTRP26, a thioredoxin‐related protein, in oxalic acid‐resistance of the brown‐rot fungus Fomitopsis palustris

“…4A and C), but decreased after day 5 of cultivation through the stationary phase (Day 5, 126.1 · 10 7 ; Day 13, 30.9 · 10 7 copy number/0.2 lg total RNA). The profile was consistent with changes in FPICL1 activity during cultivation [6]. Accordingly, the results suggest that expression of the gene encoding FpTRP26 was positively correlated with OA-accumulation, whereas FPICL1 gene expression was related with the growth phase.…”

“…FPICL1 was chosen, because FPICL1 is important during the early grow period of F. palustris on glucose [6,8,12]. The amount of FpTRP26 transcripts increased concomitantly with the accumulation of OA (Fig.…”

“…Acknowledgements: We like to thank Dr. A. Goffeau, Université Catholique de Louvain (Louvain-la-Neuve, Belgium) for kindly providing the S. cerevisiae strain AD (1)(2)(3)(4)(5)(6)(7)(8). This research was partly supported by grant in aid from Hokuto Foundation for Bioscience.…”

Genome, transcriptome, and secretome analysis of wood decay fungus Postia placenta supports unique mechanisms of lignocellulose conversion

“…6). A metabolic shunt between the citric acid and glyoxylate cycles is central to oxalic-acid accumulation by the brown-rot fungus Fomitopsis palustris (21). Analysis of the P. placenta genome demonstrates a functional glyoxylate shunt and substantially extends our understanding of the number, structure, and transcription of key genes ( Fig.…”

Properties of soils influenced by ectomycorrhizal fungi in hybrid spruce [Picea glauca × engelmannii (Moench.) Voss]

“…Paxillus involutus has also been shown to produce oxalic acid by using bicarbonate ions (Lapeyrie 1988) whereas Hysterangium crassum on Douglas-fir was found to extract Fe and Al from andesite by providing high amounts of oxalate for chelation (Cromack Jr. et al 1979). Munir et al (2001) indicated that wood-rotting basidiomycetes oxidize glucose to oxalate in order to generate energy. Wallander and Wickman (1999) showed that Pinus sylvestris (L.) seedlings colonized by Suillus variegatus appeared to be more efficient in the uptake of K from biotite than from microcline.…”