Mycosphaerella graminicola (Fückel) J. Schröt. in Cohn is a haploid ascomycete that causes septoria tritici blotch in durum ( Triticum turgidum L.) and in bread wheat (T. aesitivum L.). Two high-density genetic linkage maps with over 2000 Diversity Arrays Technology (DArT), AFLP and SSR markers were generated from two mapping populations derived from crosses between the sequenced isolate IPO323 and either isolate IPO94269 or IPO95052. Graphical genotyping revealed that some of the progenies lacked one or more linkage groups that were present in both parental isolates. PCR’s with primers derived from the SSR and DArT markers positioned on these linkage groups were used to verify the absence of these linkage groups in off spring isolates. We confirmed the absence of six linkage groups in the IPO323 x IPO94269 and IPO323 x IPO95052 progenies. We could not conclusively confirm the absence of two additional linkage groups, maybe due to the presence of translocations. We studied the origin and effect of this phenomenon. Our results demonstrate that the chromosomes were lost during meiosis possibly by non disjunction. The loss of chromosomes did not seem to affect viability, pathogenicity or fertility as back crosses between these progeny isolates and the parents produced significant numbers of off-spring isolates. The finished genome sequence of isolate IPO323 and the aligned DArT markers from the high-density map enabled us to identify the missing chromosomes containing apparently redundant genes. Interestingly, we also identified isolates in the IPO323 x IPO94269 progeny that were diploid for one linkage group. We hope our data will contribute to a better understanding of the genetics in Mycosphaerella and redundancy of its genomic content.
|Publication status||Published - 2007|
|Event||XXIV Fungal Genetics Conference - |
Duration: 20 Mar 2007 → 25 Mar 2007
|Conference||XXIV Fungal Genetics Conference|
|Period||20/03/07 → 25/03/07|