Dataset Information

Functional characterization of CgCTR2, a putative vacuole copper transporter that is involved in germination and pathogenicity in Colletotrichum gloeosporioides.

ABSTRACT: Copper is a cofactor and transition metal involved in redox reactions that are essential in all eukaryotes. Here, we report that a vacuolar copper transporter that is highly expressed in resting spores is involved in germination and pathogenicity in the plant pathogen Colletotrichum gloeosporioides. A screen of C. gloeosporioides transformants obtained by means of a promoterless green fluorescent protein (GFP) construct led to the identification of transformant N159 in which GFP signal was observed in spores. The transforming vector was inserted 70 bp upstream of a putative gene with homology to the Saccharomyces cerevisiae vacuolar copper transporter gene CTR2. The C. gloeosporioides CTR2 (CgCTR2) gene fully complemented growth defects of yeast ctr2Delta mutants, and a CgCTR2-cyan fluorescent protein (CFP) fusion protein accumulated in vacuole membranes, confirming the function of the protein as a vacuolar copper transporter. Expression analysis indicated that CgCTR2 transcript is abundant in resting conidia and during germination in rich medium and downregulated during "pathogenic" germination and the early stages of plant infection. CgCTR2 overexpression and silencing mutants were generated and characterized. The Cgctr2 mutants had markedly reduced Cu superoxide dismutase (SOD) activity, suggesting that CgCTR2 is important in providing copper to copper-dependent cytosolic activities. The Cgctr2-silenced mutants had increased sensitivity to H2O2 and reduced germination rates. The mutants were also less virulent to plants, but they did not display any defects in appressorium formation and penetration efficiency. An external copper supply compensated for the hypersensitivity to H2O2 but not for the germination and pathogenicity defects of the mutants. Similarly, overexpression of CgCTR2 enhanced resistance to H2O2 but had no effect on germination or pathogenicity. Our results show that copper is necessary for optimal germination and pathogenicity and that CgCTR2 is involved in regulating cellular copper balance during these processes.

SUBMITTER: Barhoom S

PROVIDER: S-EPMC2446676 | biostudies-literature | 2008 Jul

REPOSITORIES: biostudies-literature

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Functional characterization of CgCTR2, a putative vacuole copper transporter that is involved in germination and pathogenicity in Colletotrichum gloeosporioides.

Barhoom Sima S Kupiec Martin M Zhao Xinhua X Xu Jin-Rong JR Sharon Amir A

Eukaryotic cell 20080502 7

Copper is a cofactor and transition metal involved in redox reactions that are essential in all eukaryotes. Here, we report that a vacuolar copper transporter that is highly expressed in resting spores is involved in germination and pathogenicity in the plant pathogen Colletotrichum gloeosporioides. A screen of C. gloeosporioides transformants obtained by means of a promoterless green fluorescent protein (GFP) construct led to the identification of transformant N159 in which GFP signal was obser ...[more]

PMID: 18456860

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Project description:The limit of the Colletotrichum gloeosporioides species complex is defined genetically, based on a strongly supported clade within the Colletotrichum ITS gene tree. All taxa accepted within this clade are morphologically more or less typical of the broadly defined C. gloeosporioides, as it has been applied in the literature for the past 50 years. We accept 22 species plus one subspecies within the C. gloeosporioides complex. These include C. asianum, C. cordylinicola, C. fructicola, C. gloeosporioides, C. horii, C. kahawae subsp. kahawae, C. musae, C. nupharicola, C. psidii, C. siamense, C. theobromicola, C. tropicale, and C. xanthorrhoeae, along with the taxa described here as new, C. aenigma, C. aeschynomenes, C. alatae, C. alienum, C. aotearoa, C. clidemiae, C. kahawae subsp. ciggaro, C. salsolae, and C. ti, plus the nom. nov. C. queenslandicum (for C. gloeosporioides var. minus). All of the taxa are defined genetically on the basis of multi-gene phylogenies. Brief morphological descriptions are provided for species where no modern description is available. Many of the species are unable to be reliably distinguished using ITS, the official barcoding gene for fungi. Particularly problematic are a set of species genetically close to C. musae and another set of species genetically close to C. kahawae, referred to here as the Musae clade and the Kahawae clade, respectively. Each clade contains several species that are phylogenetically well supported in multi-gene analyses, but within the clades branch lengths are short because of the small number of phylogenetically informative characters, and in a few cases individual gene trees are incongruent. Some single genes or combinations of genes, such as glyceraldehyde-3-phosphate dehydrogenase and glutamine synthetase, can be used to reliably distinguish most taxa and will need to be developed as secondary barcodes for species level identification, which is important because many of these fungi are of biosecurity significance. In addition to the accepted species, notes are provided for names where a possible close relationship with C. gloeosporioides sensu lato has been suggested in the recent literature, along with all subspecific taxa and formae speciales within C. gloeosporioides and its putative teleomorph Glomerella cingulata.Taxonomic noveltiesName replacement - C. queenslandicum B. Weir & P.R. Johnst. New species - C. aenigma B. Weir & P.R. Johnst., C. aeschynomenes B. Weir & P.R. Johnst., C. alatae B. Weir & P.R. Johnst., C. alienum B. Weir & P.R. Johnst, C. aotearoa B. Weir & P.R. Johnst., C. clidemiae B. Weir & P.R. Johnst., C. salsolae B. Weir & P.R. Johnst., C. ti B. Weir & P.R. Johnst. New subspecies - C. kahawae subsp. ciggaro B. Weir & P.R. Johnst. Typification: Epitypification - C. queenslandicum B. Weir & P.R. Johnst.

Project description:Growth of Colletotrichum gloeosporioides in the presence of cation salts NaCl and KCl inhibited fungal growth and anthracnose symptom of colonization. Previous reports indicate that adaptation of Aspergillus nidulans to salt- and osmotic-stress conditions revealed the role of zinc-finger transcription factors SltA and CrzA in cation homeostasis. Homologs of A. nidulans SltA and CrzA were identified in C. gloeosporioides. The C. gloeosporioides CrzA homolog is a 682-amino acid protein, which contains a C2H2 zinc finger DNA-binding domain that is highly conserved among CrzA proteins from yeast and filamentous fungi. The C. gloeosporioides SltA homolog encodes a 775-amino acid protein with strong similarity to A. nidulans SltA and Trichoderma reesei ACE1, and highest conservation in the three zinc-finger regions with almost no changes compared to ACE1 sequences. Knockout of C. gloeosporioides crzA (ΔcrzA) resulted in a phenotype with inhibited growth, sporulation, germination and appressorium formation, indicating the importance of this calciu006D-activated transcription factor in regulating these morphogenetic processes. In contrast, knockout of C. gloeosporioides sltA (ΔsltA) mainly inhibited appressorium formation. Both mutants had reduced pathogenicity on mango and avocado fruit. Inhibition of the different morphogenetic stages in the ΔcrzA mutant was accompanied by drastic inhibition of chitin synthase A and B and glucan synthase, which was partially restored with Ca2+ supplementation. Inhibition of appressorium formation in ΔsltA mutants was accompanied by downregulation of the MAP kinase pmk1 and carnitine acetyl transferase (cat1), genes involved in appressorium formation and colonization, which was restored by Ca2+ supplementation. Furthermore, exposure of C. gloeosporioides ΔcrzA or ΔsltA mutants to cations such as Na+, K+ and Li+ at concentrations that the wild type C. gloeosporioides is not affected had further adverse morphogenetic effects on C. gloeosporioides which were partially or fully restored by Ca2+. Overall results suggest that both genes modulating alkali cation homeostasis have significant morphogenetic effects that reduce C. gloeosporioides colonization.

Dataset Information

Functional characterization of CgCTR2, a putative vacuole copper transporter that is involved in germination and pathogenicity in Colletotrichum gloeosporioides.

Publications

Functional characterization of CgCTR2, a putative vacuole copper transporter that is involved in germination and pathogenicity in Colletotrichum gloeosporioides.

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