Genes determining pathogenicity to pea are clustered on a supernumerary chromosome in the fungal plant pathogen Nectria haematococca.

  title={Genes determining pathogenicity to pea are clustered on a supernumerary chromosome in the fungal plant pathogen Nectria haematococca.},
  author={Y. H. Han and X. Liu and Ulla K. Benny and H. Corby Kistler and Hans D Vanetten},
  journal={The Plant journal : for cell and molecular biology},
  volume={25 3},
  • Y. HanX. Liu H. Vanetten
  • Published 1 February 2001
  • Biology, Medicine
  • The Plant journal : for cell and molecular biology
Three genes that contribute to the ability of the fungus Nectria haematococca to cause disease on pea plants have been identified. These pea pathogenicity (PEP) genes are within 25 kb of each other and are located on a supernumerary chromosome. Altogether, the PEP gene cluster contains six transcriptional units that are expressed during infection of pea tissue. The biochemical function of only one of the genes is known with certainty. This gene, PDA1, encodes a specific cytochrome P450 that… 

Figures and Tables from this paper

Distribution of the pea pathogenicity (PEP) genes in the fungus Nectria haematococca mating population VI

Isolates without PEP homologues are virulent on ripe tomato fruits and carrot roots, indicating that PEP genes are not required for pathogenicity on these hosts.

The Supernumerary Chromosome of Nectria haematococca That Carries Pea-Pathogenicity-Related Genes Also Carries a Trait for Pea Rhizosphere Competitiveness

It is established that the N. haematococca PDA1-CD chromosome, which contains the genes for pea pathogenicity on pea roots, also carries a gene(s) for the utilization of homoserine, a compound found in large amounts in pea root exudates.

Pisatin demethylase genes are on dispensable chromosomes while genes for pathogenicity on carrot and ripe tomato are on other chromosomes in Nectria haematococca.

The hypothesis that the chromosomes carrying PDA genes are dispensable and carry host-specific virulence genes while genes for pathogenicity on other hosts are carried on other chromosomes is supported.

An analysis of the phylogenetic distribution of the pea pathogenicity genes of Nectria haematococca MPVI supports the hypothesis of their origin by horizontal transfer and uncovers a potentially new pathogen of garden pea: Neocosmospora boniensis

Although no reports have been found to show that N. boniensis is a naturally occurring pea pathogen, it is shown here that this species is able to cause disease on pea and phylogenetic discontinuity supports the hypothesis that the PEP cluster originated by HGT.

Duplication of a conditionally dispensable chromosome carrying pea pathogenicity (PEP) gene clusters in Nectria haematococca.

In phenotype assays, dosage effects of PDA1 CDC in the fusion products were evident as increased virulence and homoserine-utilizing ability compared with the parents and in a separate fusion experiment, Pda1 CDC accumulated up to four copies in a haploid genome.


The presence of genes on the PDA6 and PDA1 CD chromosomes that enhance the ability of N. haematococca to expand its habitat are suggested and support the idea that fungal CD chromosomes are analogous to hostspecifying plasmids in plant-associated bacteria.

Genomic characterization of the conditionally dispensable chromosome in Alternaria arborescens provides evidence for horizontal gene transfer

Evidence supporting the hypothesis that the CDC in A. arborescens was acquired through horizontal transfer, likely from an unrelated fungus is provided and several predicted CDC genes under positive selection that may serve as candidate virulence factors are identified.

The Genome of Nectria haematococca: Contribution of Supernumerary Chromosomes to Gene Expansion

Although the origin(s) of the extra genes and the supernumerary chromosomes is not known, the gene expansion and its large genome size are consistent with this species' diverse range of habitats.

Horizontal Chromosome Transfer, a Mechanism for the Evolution and Differentiation of a Plant-Pathogenic Fungus

A hybrid strain between two different pathotypes was shown to harbor the CDCs derived from both parental strains with an expanded range of pathogenicity, indicating that CDCs can be transmitted from one strain to another and stably maintained in the new genome.



One Enzyme Makes a Fungal Pathogen, But Not a Saprophyte, Virulent on a New Host Plant

Phytoalexins can function in nonspecific resistance of plants to microbes; saprophytes appear to lack genes for basic pathogenicity.

A putative cyclic peptide efflux pump encoded by the TOXA gene of the plant-pathogenic fungus Cochliobolus carbonum.

It is proposed that TOXA encodes an HC-toxin efflux pump which contributes to self-protection against HC-Toxin and/or the secretion of HC- toxin into the extracellular milieu.

Three non-allelic genes for pisatin demethylation in the fungus Nectria haematococca

Isolates of the plant pathogenic fungus Nectria haematococca can demethylate pisatin, an isoflavonoid phytoalexin produced by pea, and this fungus appears to be linked to a gene determining female fertility in this fungus.

Mutants of Nectria haematococca created by a site-directed chromosome breakage are greatly reduced in virulence toward pea

Repeats of the simple telomeric DNA sequence and a gene from the 1.6-Mb chromosome were used to direct a chromosomal break at the PDA1 locus, the first reported use of site-directed chromosome breakage in filamentous fungi.

Nht1, a transposable element cloned from a dispensable chromosome in Nectria haematococca.

It is concluded that Nht1 is a transposable element within North American N. haematococca MPVI populations, which is highly similar to the protein encoded by the Fusarium oxysporum transposon, Fot1.

Twenty-five coregulated transcripts define a sterigmatocystin gene cluster in Aspergillus nidulans.

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  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
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restless, an active Ac-like transposon from the fungus Tolypocladium inflatum: structure, expression, and alternative RNA splicing

The genomic distribution of restless and its transcriptional expression, alternative mRNA splicing, and genomic mobility all imply a potential role for this element in developing a transposon tagging system for use in filamentous fungi.

Regulation of Pisatin Demethylation in Nectria haematococca and its Influence on Pisatin Tolerance and Virulence

SUMMARY: Nectria haematococca, a fungal pathogen of pea, demethylates the pea isoflavonoid phytoalexin pisatin to yield the less inhibitory product, 3,6a-dihydroxy-8,9-methylenedioxypterocarpan.