Molecular Plant-Microbe Interactions (2004) 17, 467-474

J. Patrick Martinez, Nicholas W. Oesch and Lynda M. Ciuffetti (2004)
Characterization of the multiple-copy host-selective toxin gene, ToxB, in pathogenic and nonpathogenic isolates of Pyrenophora tritici-repentis
Molecular Plant-Microbe Interactions 17 (5), 467-474
Abstract: ToxB, a gene that encodes a 6.6-kDa host-selective toxin (HST), is present in several races of the wheat pathogen Pyrenophora tritici-repentis. To learn more about the multiple ToxB open reading frames (ORFs), six of the estimated nine copies from a race 5 isolate were cloned and analyzed. All six copies of ToxB have identical 261-bp ORFs and thus encode the same form of Ptr ToxB. Sequence analysis of regions flanking the cloned ToxB loci revealed that the majority of loci are associated with portions of retrotransposons and a transposon-like sequence. Data indicate that ToxB loci reside on two chromosomes, 3.5 and 2.7 Mb, with the majority of copies located on the 2.7 Mb chromosome. A related gene, referred to as toxb, from a nonpathogenic race 4 isolate was also cloned and characterized. This is interesting because, until now, HST genes have only been found in toxin-producing, pathogenic isolates of plant pathogenic fungi. The toxb gene from nonpathogenic isolates is 86% similar to ToxB, and data suggest that toxb is a single-copy gene. No toxb transcript was detected under culture conditions that favor the expression of ToxB; therefore, these genes differ in their transcriptional regulation.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Lynda M. Ciuffetti

Research topic(s) for pests/diseases/weeds:
molecular biology - genes

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Pyrenophora tritici-repentis	Wheat (Triticum)