Functional analyses of individual mating-type transcripts atMATloci inFusarium graminearumandFusarium asiaticum

Abstract

Members of the Fusarium graminearum species (Fg) complex, which are homothallic ascomycetous species, carry two opposite mating-type (MAT) loci in a single nucleus for controlling sexual development. We investigated the roles of three (MAT1-1-1, MAT1-1-2, and MAT1-1-3) and two (MAT1-2-1 and MAT1-2-3) transcripts located at both loci in representative Fg complex species (F. graminearum and Fusarium asiaticum). In self-fertile F. graminearum strains, the transcript levels of MAT1-1-1, MAT1-2-1, and MAT1-2-3 peaked 2 days after sexual induction (dai) and then remained high until 12 dai, whereas MAT1-1-2 and MAT1-1-3 transcripts reached peak levels between 4 and 8 dai. In contrast, all of the MAT transcripts in self-sterile F. asiaticum strains accumulated at much lower levels than those in F. graminearum during the entire time. Targeted gene deletions confirmed that MAT1-1-1, MAT1-1-2, MAT1-1-3, and MAT1-2-1 were essential for self-fertility in F. graminearum, but MAT1-2-3 was not. All MAT-deleted strains (except ΔMAT1-2-3) produced recombinant perithecia when outcrossed to a self-fertile strain. These results indicate that developmental up-regulation of the individual MAT genes in both a proper fashion and quantity is critical for sexual development, and that alterations in the gene expression could be attributed to the variation in self-sterility among the Fg complex.

The caterpillar fungus, Ophiocordyceps sinensis, genome provides insights into highland adaptation of fungal pathogenicity

“…acridum (MAT1-2) 19 , which are heterothallic and possess only a single mating-type locus. Similar to the well-known homothallic plant pathogen Fusarium graminearum 34 , the organization of these two MAT loci in O . sinensis revealed the fusion status within the idiomorphic genomic region, which was particularly enriched in LTR retrotransponsons.…”

Comparison of Trichothecene Biosynthetic Gene Expression between Fusarium graminearum and Fusarium asiaticum

“…At this time, extensive comparisons between NIV and DON strains have been performed for genes controlling trichothecene production and sexual reproduction, such as those located at the mating type ( MAT ) loci (Kim et al, 2012) and trichothecene gene clusters (Kimura et al, 2003; Lee et al, 2001). These studies have revealed more than 80% nucleotide similarity between the two chemotype strains.…”

“…As described above, nucleotide polymorphisms of TRI13 and TRI7 are known to determine trichothecene chemotypes of F. graminearum and F. asiaticum (Lee et al, 2001; Lee et al, 2002). Alterations in individual MAT gene expression is thought to be due to variations in self-fertility between two chemotype strains; the majority of NIV-producing F. asiaticum showed a lower self-fertility than the highly fertile DON-producing F. graminearum strains (Kim et al, 2012; Lee et al, 2009, 2012). At this time, genome sequencing of a Korean F. asiaticum strain is almost complete, which will allow comparisons to be made at the whole genome level (Yun et al, unpublished data).…”

Functional Roles of FgLaeA in Controlling Secondary Metabolism, Sexual Development, and Virulence in Fusarium graminearum

“…qRT-PCR analysis confirmed that the transcript levels of two MAT genes ( MAT1-1-1 and MAT1-2-1 , both of which are required for early sexual stage development in F. graminearum [39]), were elevated ∼2–3-fold in the Δ FgLaeA strain compared to the WT strain 24 h after perithecial induction on carrot agar (Fig. 3B); no changes were observed in the OE and add-back strains during the same time points for perithecial induction compared to those in WT (Fig.…”