Homologous recombination causes the spontaneous deletion of AVR‐Pia in Magnaporthe oryzae. Issue 2 (27th December 2012)

• Record Type: Journal Article
• Authors: Sone, Teruo; Takeuchi, Saori; Miki, Shinsuke; Satoh, Yuki; Ohtsuka, Keisuke; Abe, Ayumi; Asano, Kozo
• Is Part Of: FEMS microbiology letters. Volume 339:Issue 2(2013:Feb.)
• Page Start: 102
• Page End: 109
• Publication Date: 2012-12-27
• Subjects: Microbiology -- Periodicals; 579
• DOI: 10.1111/1574-6968.12058
• Languages: English
• ISSNs: 0378-1097

Abstract

<abstract abstract-type="main" id="fml12058-abs-0001"> <title>Abstract</title> <p> <italic>AVR‐Pia</italic>, an avirulence gene in the genome of the rice blast fungus <italic>Magnaporthe oryzae</italic>, triggers a hypersensitive reaction in rice cultivars harbouring the resistance gene <italic>Pia</italic>. The copy number of <italic>AVR‐Pia</italic> was revealed to vary from one to three among <italic>M. oryzae</italic> isolates avirulent to <italic>Pia</italic> rice, and three copies of the gene were located on a single chromosome in strain Ina168, from which the gene was originally cloned. The spontaneous <italic>avr‐Pia</italic> mutant originated from Ina168, named Ina168m95‐1, which lacks the <italic>AVR‐Pia</italic> gene, and was therefore used to elucidate the molecular mechanism of the deletion of all three copies of <italic>AVR‐Pia</italic>. Screening and analysis of cosmid clones indicated that two copies of the DNA‐type transposon <italic>Occan</italic> (<italic>Occan</italic><sup>9E12</sup> and <italic>Occan</italic><sup>3A3</sup>) were located on the same chromosome, and three copies of <italic>AVR‐Pia</italic> were located in between the two <italic>Occan</italic> elements. Ina168m95‐1 contains a conserved <italic>Occan</italic> element, named <italic>Occan</italic><sup>m95‐1</sup>, between sequences homologous to the 5′‐flanking region of <italic>Occan</italic><sup>3A3</sup> and the 3′‐flanking region of <italic>Occan</italic><sup>9E12</sup>. In addition, sequence polymorphisms indicated a homologous recombination between <italic>Occan</italic><sup>3A3</sup> and <italic>Occan</italic><sup>9E12</sup>, which resulted in <italic>Occan</italic><sup>m95‐1</sup>. Based on these observations, we propose the hypothesis that homologous recombination in the two <italic>Occan</italic> elements leads to the deletion of <italic>AVR‐Pia</italic> in Ina168m95‐1.</p> </abstract>