Abstract
Alternaria citri, the cause of Alternaria black rot, and Alternaria alternata rough lemon pathotype, the cause of Alternaria brown spot, are morphologically indistinguishable pathogens of citrus: one causes rot by macerating tissues and the other causes necrotic spots by producing a host-selective toxin. To evaluate the role of endopolygalacturonase (endoPG) in pathogenicity of these two Alternaria spp. pathogens, their genes for endoPG were mutated by gene targeting. The endoPGs produced by these fungi have similar biochemical properties, and the genes are highly similar (99.6% nucleotide identity). The phenotypes of the mutants, however, are completely different. An endoPG mutant of A. citri was significantly reduced in its ability to cause black rot symptoms on citrus as well as in the maceration of potato tissue and could not colonize citrus peel segments. In contrast, an endoPG mutant of A. alternata was unchanged in pathogenicity. The results indicate that a cell wall-degrading enzyme can play different roles in the pathogenicity of fungal pathogens. The role of a cell wall-degrading enzyme depends upon the type of disease but not the taxonomy of the fungus.
| Original language | English |
|---|---|
| Pages (from-to) | 749-757 |
| Number of pages | 9 |
| Journal | Molecular Plant-Microbe Interactions |
| Volume | 14 |
| Issue number | 6 |
| Publication status | Published - Jun 2001 |
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Keywords
- ACR-toxin
- Host-specific toxin
- Pectinase
ASJC Scopus subject areas
- Microbiology
- Biochemistry, Genetics and Molecular Biology(all)
- Biochemistry
- Biotechnology
Cite this
Endopolygalacturonase is essential for citrus black rot caused by Alternaria citri but not brown spot caused by Alternaria alternata. / Isshiki, Atsunori; Akimitsu, Kazuya; Yamamoto, Mikihiro; Yamamoto, Hiroyuki.
In: Molecular Plant-Microbe Interactions, Vol. 14, No. 6, 06.2001, p. 749-757.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Endopolygalacturonase is essential for citrus black rot caused by Alternaria citri but not brown spot caused by Alternaria alternata
AU - Isshiki, Atsunori
AU - Akimitsu, Kazuya
AU - Yamamoto, Mikihiro
AU - Yamamoto, Hiroyuki
PY - 2001/6
Y1 - 2001/6
N2 - Alternaria citri, the cause of Alternaria black rot, and Alternaria alternata rough lemon pathotype, the cause of Alternaria brown spot, are morphologically indistinguishable pathogens of citrus: one causes rot by macerating tissues and the other causes necrotic spots by producing a host-selective toxin. To evaluate the role of endopolygalacturonase (endoPG) in pathogenicity of these two Alternaria spp. pathogens, their genes for endoPG were mutated by gene targeting. The endoPGs produced by these fungi have similar biochemical properties, and the genes are highly similar (99.6% nucleotide identity). The phenotypes of the mutants, however, are completely different. An endoPG mutant of A. citri was significantly reduced in its ability to cause black rot symptoms on citrus as well as in the maceration of potato tissue and could not colonize citrus peel segments. In contrast, an endoPG mutant of A. alternata was unchanged in pathogenicity. The results indicate that a cell wall-degrading enzyme can play different roles in the pathogenicity of fungal pathogens. The role of a cell wall-degrading enzyme depends upon the type of disease but not the taxonomy of the fungus.
AB - Alternaria citri, the cause of Alternaria black rot, and Alternaria alternata rough lemon pathotype, the cause of Alternaria brown spot, are morphologically indistinguishable pathogens of citrus: one causes rot by macerating tissues and the other causes necrotic spots by producing a host-selective toxin. To evaluate the role of endopolygalacturonase (endoPG) in pathogenicity of these two Alternaria spp. pathogens, their genes for endoPG were mutated by gene targeting. The endoPGs produced by these fungi have similar biochemical properties, and the genes are highly similar (99.6% nucleotide identity). The phenotypes of the mutants, however, are completely different. An endoPG mutant of A. citri was significantly reduced in its ability to cause black rot symptoms on citrus as well as in the maceration of potato tissue and could not colonize citrus peel segments. In contrast, an endoPG mutant of A. alternata was unchanged in pathogenicity. The results indicate that a cell wall-degrading enzyme can play different roles in the pathogenicity of fungal pathogens. The role of a cell wall-degrading enzyme depends upon the type of disease but not the taxonomy of the fungus.
KW - ACR-toxin
KW - Host-specific toxin
KW - Pectinase
UR - http://www.scopus.com/inward/record.url?scp=0035018083&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035018083&partnerID=8YFLogxK
M3 - Article
C2 - 11386370
AN - SCOPUS:0035018083
VL - 14
SP - 749
EP - 757
JO - Molecular Plant-Microbe Interactions
JF - Molecular Plant-Microbe Interactions
SN - 0894-0282
IS - 6
ER -