2015 journal article

Membrane transporters in self resistance of Cercospora nicotianae to the photoactivated toxin cercosporin

CURRENT GENETICS, 61(4), 601–620.

author keywords: Perylenequinone; Photosensitizer resistance; ABC transporter; MFS transporter; Targeted gene disruption; CRG1; CnATR1; CnCFP
MeSH headings : ATP-Binding Cassette Transporters / genetics; ATP-Binding Cassette Transporters / metabolism; Antifungal Agents / metabolism; Antifungal Agents / pharmacology; Drug Resistance, Fungal / genetics; Fungal Proteins / genetics; Fungal Proteins / metabolism; Gene Expression Regulation, Fungal; Gene Targeting; Membrane Transport Proteins / genetics; Membrane Transport Proteins / metabolism; Neurospora crassa / drug effects; Neurospora crassa / genetics; Neurospora crassa / metabolism; Perylene / analogs & derivatives; Perylene / metabolism; Perylene / pharmacology; Photosensitizing Agents / metabolism; Photosensitizing Agents / pharmacology; Phylogeny; Saccharomycetales / classification; Saccharomycetales / drug effects; Saccharomycetales / genetics; Saccharomycetales / metabolism; Singlet Oxygen / metabolism; Uracil / metabolism; Zinc / metabolism
TL;DR: It is concluded that cercosporin autoresistance in Cercospora is mediated by multiple genes, and that the fungus compensates for mutations by up-regulation of other resistance genes. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Source: Web Of Science
Added: August 6, 2018

The goal of this work is to characterize membrane transporter genes in Cercospora fungi required for autoresistance to the photoactivated, active-oxygen-generating toxin cercosporin they produce for infection of host plants. Previous studies implicated a role for diverse membrane transporters in cercosporin resistance. In this study, transporters identified in a subtractive cDNA library between a Cercospora nicotianae wild type and a cercosporin-sensitive mutant were characterized, including two ABC transporters (CnATR2, CnATR3), an MFS transporter (CnMFS2), a uracil transporter, and a zinc transport protein. Phylogenetic analysis showed that only CnATR3 clustered with transporters previously characterized to be involved in cercosporin resistance. Quantitative RT-PCR analysis of gene expression under conditions of cercosporin toxicity, however, showed that only CnATR2 was upregulated, thus this gene was selected for further characterization. Transformation and expression of CnATR2 in the cercosporin-sensitive fungus Neurospora crassa significantly increased cercosporin resistance. Targeted gene disruption of CnATR2 in the wild type C. nicotianae, however, did not decrease resistance. Expression analysis of other transporters in the cnatr2 mutant under conditions of cercosporin toxicity showed significant upregulation of the cercosporin facilitator protein gene (CFP), encoding an MFS transporter previously characterized as playing an important role in cercosporin autoresistance in Cercospora species. We conclude that cercosporin autoresistance in Cercospora is mediated by multiple genes, and that the fungus compensates for mutations by up-regulation of other resistance genes. CnATR2 may be a useful gene, alone or in addition to other known resistance genes, for engineering Cercospora resistance in crop plants.