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The white collar complex is involved in sexual development of Fusarium graminearum.

Kim H, Kim HK, Lee S, Yun SH - PLoS ONE (2015)

Bottom Line: Deletion of FgFph had no significant effect on sexual development or MAT gene expression.In contrast, all of the deletion strains examined did not show significant changes in other traits such as hyphal growth, mycotoxin production, and virulence.Taken together, these results demonstrate that FgWc-1 and FgWc-2, two central components of the blue-light sensing system, negatively regulate sexual development in F. graminearum, which differs from the regulation pattern in A. nidulans.

View Article: PubMed Central - PubMed

Affiliation: Research Center for Biobased Chemistry, Division of Convergence Chemistry, Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea.

ABSTRACT
Sexual spores (ascospores) of Fusarium graminearum, a homothallic ascomycetous fungus, are believed to be the primary inocula for epidemics of the diseases caused by this species in cereal crops. Based on the light requirement for the formation of fruiting bodies (perithecia) of F. graminearum under laboratory conditions, we explored whether photoreceptors play an important role in sexual development. Here, we evaluated the roles of three genes encoding putative photoreceptors [a phytochrome gene (FgFph) and two white collar genes (FgWc-1 and FgWc-2)] during sexual development in F. graminearum. For functional analyses, we generated transgenic strains lacking one or two genes from the self-fertile Z3643 strain. Unlike the wild-type (WT) and add-back strains, the single deletion strains (ΔFgWc-1 and ΔFgWc-2) produced fertile perithecia under constant light on complete medium (CM, an unfavorable medium for sexual development) as well as on carrot agar (a perithecial induction condition). The expression of mating-type (MAT) genes increased significantly in the gene deletion strains compared to the WT under both conditions. Deletion of FgFph had no significant effect on sexual development or MAT gene expression. In contrast, all of the deletion strains examined did not show significant changes in other traits such as hyphal growth, mycotoxin production, and virulence. A split luciferase assay confirmed the in vivo protein-protein interactions among three photoreceptors along with FgLaeA, a global regulator of secondary metabolism and fungal development. Introduction of an intact copy of the A. nidulans LreA and LreB genes, which are homologs of FgWc-1 and FgWc-2, into the ΔFgWc-1 and ΔFgWc-2 strains, respectively, failed to repress perithecia formation on CM in the gene deletion strains. Taken together, these results demonstrate that FgWc-1 and FgWc-2, two central components of the blue-light sensing system, negatively regulate sexual development in F. graminearum, which differs from the regulation pattern in A. nidulans.

No MeSH data available.


Related in: MedlinePlus

Mycelial growth of F. graminearum strains on complete medium.Cultures were grown in constant light (upper panel) and darkness (lower panel) for 6 days. Photographs were taken on the tops of the plates.
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pone.0120293.g001: Mycelial growth of F. graminearum strains on complete medium.Cultures were grown in constant light (upper panel) and darkness (lower panel) for 6 days. Photographs were taken on the tops of the plates.

Mentions: To functionally characterize the role of the photoreceptors in F. graminearum, FgWc-1, FgWc-2, and FgFph were deleted from the genomes of the Z3643 or FLTRI6 strain via double-crossover approaches, in which the predicted coding region of each gene was replaced with a geneticin resistance cassette (S3 Fig.). Each deletion mutant was complemented by introducing the WT allele with pBCATPH carrying the hyg gene. Additionally, we generated a FgWc-1 and FgWc-2 double-deletion strain (designated ΔFgWc-1/2), in which FgWc-2 of strain ΔFgWc-1 was replaced with the hyg cassette. All strains created in this study were confirmed by PCR (S3 Fig.). For phenotypic analyses, strains deleted in each gene were selected and named ΔFgWc-1, ΔFgWc-2, and ΔFgFph. Compared with the WT strain, deletion and complementation strains were phenotypically indistinguishable in terms of radial growth, hyphal morphology, and pigmentation regardless of the presence of light when cultured on a variety of growth media (data not shown). In addition, these deletion strains showed no significant changes in trichothecene production, response to various stresses (S4A and S5 Figs), or virulence towards host plants (data not shown). However, ΔFgWc-1 and ΔFgWc-2 showed more aerial mycelia when grown under constant light (Fig. 1), and ΔFgWc-1 and ΔFgWc-1/2 exhibited reduced conidiation on complete medium compared to WT (with ∼3.2- and ∼5.4-fold-changes, respectively) (S4B Fig.). Based on these observations, FgWc-1, FgWc-2, and FgFph did not severely affect in hypahl growth, secondary metabolism, stress response, or virulence compared to WT, unlike the photoreceptors previously characterized in other fungal species.


The white collar complex is involved in sexual development of Fusarium graminearum.

Kim H, Kim HK, Lee S, Yun SH - PLoS ONE (2015)

Mycelial growth of F. graminearum strains on complete medium.Cultures were grown in constant light (upper panel) and darkness (lower panel) for 6 days. Photographs were taken on the tops of the plates.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4364711&req=5

pone.0120293.g001: Mycelial growth of F. graminearum strains on complete medium.Cultures were grown in constant light (upper panel) and darkness (lower panel) for 6 days. Photographs were taken on the tops of the plates.
Mentions: To functionally characterize the role of the photoreceptors in F. graminearum, FgWc-1, FgWc-2, and FgFph were deleted from the genomes of the Z3643 or FLTRI6 strain via double-crossover approaches, in which the predicted coding region of each gene was replaced with a geneticin resistance cassette (S3 Fig.). Each deletion mutant was complemented by introducing the WT allele with pBCATPH carrying the hyg gene. Additionally, we generated a FgWc-1 and FgWc-2 double-deletion strain (designated ΔFgWc-1/2), in which FgWc-2 of strain ΔFgWc-1 was replaced with the hyg cassette. All strains created in this study were confirmed by PCR (S3 Fig.). For phenotypic analyses, strains deleted in each gene were selected and named ΔFgWc-1, ΔFgWc-2, and ΔFgFph. Compared with the WT strain, deletion and complementation strains were phenotypically indistinguishable in terms of radial growth, hyphal morphology, and pigmentation regardless of the presence of light when cultured on a variety of growth media (data not shown). In addition, these deletion strains showed no significant changes in trichothecene production, response to various stresses (S4A and S5 Figs), or virulence towards host plants (data not shown). However, ΔFgWc-1 and ΔFgWc-2 showed more aerial mycelia when grown under constant light (Fig. 1), and ΔFgWc-1 and ΔFgWc-1/2 exhibited reduced conidiation on complete medium compared to WT (with ∼3.2- and ∼5.4-fold-changes, respectively) (S4B Fig.). Based on these observations, FgWc-1, FgWc-2, and FgFph did not severely affect in hypahl growth, secondary metabolism, stress response, or virulence compared to WT, unlike the photoreceptors previously characterized in other fungal species.

Bottom Line: Deletion of FgFph had no significant effect on sexual development or MAT gene expression.In contrast, all of the deletion strains examined did not show significant changes in other traits such as hyphal growth, mycotoxin production, and virulence.Taken together, these results demonstrate that FgWc-1 and FgWc-2, two central components of the blue-light sensing system, negatively regulate sexual development in F. graminearum, which differs from the regulation pattern in A. nidulans.

View Article: PubMed Central - PubMed

Affiliation: Research Center for Biobased Chemistry, Division of Convergence Chemistry, Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea.

ABSTRACT
Sexual spores (ascospores) of Fusarium graminearum, a homothallic ascomycetous fungus, are believed to be the primary inocula for epidemics of the diseases caused by this species in cereal crops. Based on the light requirement for the formation of fruiting bodies (perithecia) of F. graminearum under laboratory conditions, we explored whether photoreceptors play an important role in sexual development. Here, we evaluated the roles of three genes encoding putative photoreceptors [a phytochrome gene (FgFph) and two white collar genes (FgWc-1 and FgWc-2)] during sexual development in F. graminearum. For functional analyses, we generated transgenic strains lacking one or two genes from the self-fertile Z3643 strain. Unlike the wild-type (WT) and add-back strains, the single deletion strains (ΔFgWc-1 and ΔFgWc-2) produced fertile perithecia under constant light on complete medium (CM, an unfavorable medium for sexual development) as well as on carrot agar (a perithecial induction condition). The expression of mating-type (MAT) genes increased significantly in the gene deletion strains compared to the WT under both conditions. Deletion of FgFph had no significant effect on sexual development or MAT gene expression. In contrast, all of the deletion strains examined did not show significant changes in other traits such as hyphal growth, mycotoxin production, and virulence. A split luciferase assay confirmed the in vivo protein-protein interactions among three photoreceptors along with FgLaeA, a global regulator of secondary metabolism and fungal development. Introduction of an intact copy of the A. nidulans LreA and LreB genes, which are homologs of FgWc-1 and FgWc-2, into the ΔFgWc-1 and ΔFgWc-2 strains, respectively, failed to repress perithecia formation on CM in the gene deletion strains. Taken together, these results demonstrate that FgWc-1 and FgWc-2, two central components of the blue-light sensing system, negatively regulate sexual development in F. graminearum, which differs from the regulation pattern in A. nidulans.

No MeSH data available.


Related in: MedlinePlus