Characterization of a novel NADP+-dependent D-arabitol dehydrogenase from the plant pathogen Uromyces fabae

Abstract

We have identified and characterized a novel NADP(+)-dependent D-arabitol dehydrogenase and the corresponding gene from the rust fungus Uromyces fabae, a biotrophic plant pathogen on broad bean (Vicia faba). The new enzyme was termed ARD1p (D-arabitol dehydrogenase 1). It recognizes D-arabitol and mannitol as substrates in the forward reaction, and D-xylulose, D-ribulose and D-fructose as substrates in the reverse reaction. Co-factor specificity was restricted to NADP(H). Kinetic data for the major substrates and co-factors are presented. A detailed analysis of the organization and expression pattern of the ARD1 gene are also given. Immunocytological data indicate a localization of the gene product predominantly in haustoria, the feeding structures of these fungi. Analyses of metabolite levels during pathogenesis indicate that the D-arabitol concentration rises dramatically as infection progresses, and D-arabitol was shown in an in vitro system to be capable of quenching reactive oxygen species involved in host plant defence reactions. ARD1p may therefore play an important role in carbohydrate metabolism and in establishing and/or maintaining the biotrophic interaction in U. fabae.

Transcriptome analysis of enriched Golovinomyces orontii haustoria by deep 454 pyrosequencing

“…These results are congruent with a microarray study of the bean rust fungus, U. fabae, in which genes coding for a mannitol dehydrogenase, a manganese superoxide dismutase and a metallothionein were among the most highly up-regulated genes in rust-infected leaves compared to germinated spores (Jakupovic et al, 2006). U. fabae has been shown to produce the ROS-scavenging compounds mannitol and arabitol during infection and to release these compounds into the plant apoplastic space, implicating mannitol dehydrogenases in ROS detoxification (Link et al, 2005). The presumed important role of ROS scavenging in infections is further underlined by the discovery of several enzymes involved in the response to oxidative stress in proteomic studies on Bgh haustoria (Bindschedler et al, 2009(Bindschedler et al, , 2011Godfrey et al, 2009).…”

Metabolic response induced by parasitic plant-fungus interactions hinder amino sugar and nucleotide sugar metabolism in the host

“…Accumulation of mannitol and its transformation into fructose were revealed not only by our study but also by previous studies1619. With regard to other accumulated sugar alcohols, arabitol has also been identified as a quencher of reactive oxygen species (ROS); the others, erythritol and xylitol, have been reported to accumulate in some infected hosts202122. However, those studies did not consider simultaneous accumulation of these 4 sugar alcohols.…”

Mannitol metabolism in the phytopathogenic fungus Alternaria alternata

“…This result suggests that the fungus contains other enzymes that utilize mannitol as a substrate. Others have shown that the enzymes ribitol-5-phosphate 2-dehydrogenase (EC 1.1.1.137), xylitol dehydrogenase (EC 1.1.1.9), glycerol dehydrogenase (EC 1.1.1.72), arabinitol dehydrogenase (EC 1.1.1.287) and arabinitol dehydrogenase (EC 1.1.1.250) utilize mannitol as a substrate (Jennings, 1984;Sealy-Lewis and Fairhurst, 1992;Hallborn et al, 1995;Link et al, 2005).…”