The MAT Locus Genes Play Different Roles in Sexual Reproduction and Pathogenesis in Fusarium graminearum

Fusarium graminearum is an important pathogen of small grains and maize in many areas of the world. Infected grains are often contaminated with mycotoxins harmful to humans and animals. During the past decade, F. graminearum has caused several severe epidemics of head scab in wheat and barley. In order to understand molecular mechanisms regulating fungal development and pathogenicity in this pathogen, we isolated and characterized a MAP kinase gene, MGV1, which is highly homologous to the MPS1 gene in Magnaporthe grisea. The MGV1 gene was dispensable for conidiation in F. graminearum but essential for female fertility during sexual reproduction. Vegetative growth of mgv1 deletion mutants was normal in liquid media but reduced on solid media. Mycelia of the mgv1 mutants had weak cell walls and were hypersensitive to cell wall degrading enzymes. Interestingly, the mgv1 mutants were self-incompatible when tested for heterokaryon formation, and their virulence was substantially reduced. The ability of the mutants to accumulate trichothecene mycotoxins on inoculated wheat was also greatly reduced. Our data suggest that MGV1 in F. graminearum is involved in multiple developmental processes related to sexual reproduction, plant infection, and cell wall integrity.

Download Full-text

Functional roles of α 1 -, α 2 -, β 1 -, β 2 -tubulin in vegetative growth, microtubule assembly and sexual reproduction of Fusarium graminearum .

Applied and Environmental Microbiology ◽

10.1128/aem.00967-21 ◽

2021 ◽

Author(s):

Yuanye Zhu ◽

Yuanshuai Zhang ◽

Yabing Duan ◽

Dongya Shi ◽

Yi ping Hou ◽

...

Keyword(s):

Sexual Reproduction ◽

Fusarium Graminearum ◽

Vegetative Growth ◽

Microtubule Assembly ◽

Mitochondrial Outer Membrane ◽

Deletion Mutants ◽

Voltage Dependent Anion Channel ◽

Microtubule Cytoskeleton ◽

Functional Roles ◽

Β Tubulin

The plant pathogen Fusarium graminearum contains two α-tubulin (α 1 and α 2 ) isotypes and two β-tubulin isotypes (β 1 and β 2 ). The functional roles of these tubulins in microtubule assembly are not clear. Previous studies showed that α 1 - and β 2 -tubulin deletion mutants showed severe growth defects and hypersensitivity to carbendazim, which have not been well explained. Here, we investigated the interaction between α- and β-tubulin of F. graminearum . Co-localization experiments demonstrated that β 1 - and β 2 -tubulin are co-localized. Co-immunoprecipitation experiment suggested that β 1 -tubulin binds to both α 1 - and α 2 -tubulin and β 2 -tubulin can also bind to α 1 - or α 2 -tubulin. Interestingly, deletion of α 1 -tubulin increased the interaction between β 2 -tubulin and α 2 -tubulin. Microtubule observation assays showed that deletion of α 1 -tubulin completely disrupted β 1 -tubulin-containing microtubules and significantly decreased β 2 -tubulin-containing microtubules. Deletion of α 2 -, β 1 - or β 2 -tubulin respectively had no obvious effect on the microtubule cytoskeleton. However, microtubules in α 1 - and β 2 -tubulin deletion mutants were easily depolymerized in the presence of carbendazim. The sexual reproduction assay indicates that α 1 - and β 1 -tubulin deletion mutants could not produce asci and ascospores. These results implied that α 1 -tubulin may be essential for the microtubule cytoskeleton. However, our Δα 1 -2×α 2 mutant (α 1 -tubulin deletion mutant containing two copies of α 2 -tubulin) exhibited a normal microtubule network, growth and sexual reproduction. Interestingly, the Δα 1 -2×α 2 mutant was still hypersensitive to carbendazim. In addition, both β 1 -tubulin and β 2 -tubulin were found to bind the mitochondrial outer membrane voltage-dependent anion channel (VDAC), indicating they could regulate the function of VDAC. Importance: In this study, we found that F. graminearum contains four different α-/β-tubulin heterodimers (α 1 -β 1 , α 1 -β 2 , α 2 -β 1 and α 2 -β 2 ) and they assemble together into a single microtubule. Moreover, α 1 -, α 2 -tubulins are functionally interchangeable in microtubule assembly, vegetative growth and sexual reproduction. These results provide more insights into functional roles of different tubulins of F. graminearum which could be helpful for purification of tubulin heterodimers and developing new tubulin-binding agents.

Download Full-text

FgVelB globally regulates sexual reproduction, mycotoxin production and pathogenicity in the cereal pathogen Fusarium graminearum

Microbiology ◽

10.1099/mic.0.059188-0 ◽

2012 ◽

Vol 158 (7) ◽

pp. 1723-1733 ◽

Cited By ~ 38

Author(s):

Jungkwan Lee ◽

Kilseon Myong ◽

Jung-Eun Kim ◽

Hee-Kyoung Kim ◽

Sung-Hwan Yun ◽

...

Keyword(s):

Sexual Reproduction ◽

Fusarium Graminearum ◽

Mycotoxin Production

Download Full-text

The HDF1 Histone Deacetylase Gene Is Important for Conidiation, Sexual Reproduction, and Pathogenesis in Fusarium graminearum

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-10-10-0233 ◽

2011 ◽

Vol 24 (4) ◽

pp. 487-496 ◽

Cited By ~ 48

Author(s):

Yimin Li ◽

Chenfang Wang ◽

Wende Liu ◽

Guanghui Wang ◽

Zhensheng Kang ◽

...

Keyword(s):

Sexual Reproduction ◽

Histone Deacetylase ◽

Fusarium Graminearum ◽

Chromatin Modification ◽

Class Ii ◽

In Planta ◽

Head Blight ◽

Obvious Effect ◽

A Minor ◽

And Function

Head blight caused by Fusarium graminearum is an important disease of wheat and barley. Its genome contains chromosomal regions with higher genetic variation and enriched for genes expressed in planta, suggesting a role of chromatin modification in the regulation of infection-related genes. In a previous study, the FTL1 gene was characterized as a novel virulence factor in the head blight fungus. FTL1 is homologous to yeast SIF2, which is a component of the Set3 complex. Many members of the yeast Set3 complex, including Hos2 histone deacetylase (HDAC), are conserved in F. graminearum. In this study, we characterized the HDF1 gene that is orthologous to HOS2. HDF1 physically interacted with FTL1 in yeast two-hybrid assays. Deletion of HDF1 resulted in a significant reduction in virulence and deoxynivalenol (DON) production. The Δhdf1 mutant failed to spread from the inoculation site to other parts of wheat heads or corn stalks. It was defective in sexual reproduction and significantly reduced in conidiation. Expression of HDF1 was highest in conidia in comparison with germlings and hyphae. Deletion of HDF1 also resulted in a 60% reduction in HDAC activity. Microarray analysis revealed that 149 and 253 genes were down- and upregulated, respectively, over fivefold in the Δhdf1 mutant. Consistent with upregulation of putative catalase and peroxidase genes, the Δhdf1 mutant was more tolerant to H2O2 than the wild type. Deletion of the other two class II HDAC genes had no obvious effect on vegetative growth and resulted in only a minor reduction in conidiation and virulence in the Δhdf2 mutant. Overall, our results indicate that HDF1 is the major class II HDAC gene in F. graminearum. It may interact with FTL1 and function as a component in a well-conserved HDAC complex in the regulation of conidiation, DON production, and pathogenesis.

Download Full-text

A Novel Transcriptional Factor Important for Pathogenesis and Ascosporogenesis in Fusarium graminearum

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-06-10-0129 ◽

2011 ◽

Vol 24 (1) ◽

pp. 118-128 ◽

Cited By ~ 46

Author(s):

Yang Wang ◽

Wende Liu ◽

Zhanming Hou ◽

Chenfang Wang ◽

Xiaoying Zhou ◽

...

Keyword(s):

Transcription Factor ◽

Sexual Reproduction ◽

Fusarium Graminearum ◽

Fungal Pathogens ◽

Insertional Mutagenesis ◽

Gene Replacement ◽

Normal Male ◽

Head Blight ◽

Function Expression ◽

Female Specific

Fusarium head blight or scab caused by Fusarium graminearum is an important disease of wheat and barley. The pathogen not only causes severe yield losses but also contaminates infested grains with mycotoxins. In a previous study, we identified several pathogenicity mutants by random insertional mutagenesis. One of these mutants was disrupted in the ZIF1 gene, which encodes a b-ZIP transcription factor unique to filamentous ascomycetes. The Δzif1 mutant generated by gene replacement was significantly reduced in deoxynivalenol (DON) production and virulence on flowering wheat heads. It was defective in spreading from inoculated florets to the rachis and other spikelets. Deletion of the ZIF1 ortholog MoZIF1 in the rice blast fungus also caused reductions in virulence and in invasive growth. In addition, the Δzif1 mutant is defective in sexual reproduction. Although it had normal male fertility, when selfed or mated as the female in outcrosess, the Δzif1 mutant produced small, pigmented perithecia that were sterile (lack of asci and ascospores), suggesting a female-specific role for ZIF1 during fertilization or ascus development. Similar female-specific defects in sexual reproduction were observed in the ΔMozif1 mutant. When mated as the female, the ΔMozif1 perithecia failed to develop long necks and asci or ascospores. The ZIF1 gene is well conserved in filamentous ascomycetes, particularly in the b-ZIP domain, which is essential for its function. Expression of ZIF1 in Magnaporthe oryzae complemented the defects of the ΔMozif1 mutant. These results indicate that this b-ZIP transcription factor is functionally conserved in these two fungal pathogens for plant infection and sexual reproduction.

Download Full-text

FgSfl1 and Its Conserved PKA Phosphorylation Sites Are Important for Conidiation, Sexual Reproduction, and Pathogenesis in Fusarium graminearum

Journal of Fungi ◽

10.3390/jof7090755 ◽

2021 ◽

Vol 7 (9) ◽

pp. 755

Author(s):

Chen Gong ◽

Junqi Huang ◽

Daiyuan Sun ◽

Daiying Xu ◽

Yuqian Guo ◽

...

Keyword(s):

Sexual Reproduction ◽

Fusarium Graminearum ◽

Double Mutant ◽

Deletion Mutant ◽

Phosphorylation Site ◽

Phosphorylation Sites ◽

Catalytic Subunits ◽

Cellular Processes ◽

Plant Infection ◽

Dependent Protein

The fungal plant pathogen, Fusarium graminearum, contains two genes, FgCPK1 and FgCPK2, encoding the catalytic subunits of cAMP-dependent protein kinase A. FgCPK1 and FgCPK2 are responsible for most of the PKA activities and have overlapping functions in various cellular processes in F. graminearum. The cpk1 cpk2 double mutant was significantly reduced in growth, rarely produced conidia, and was non-pathogenic. In this study, we found that the cpk1 cpk2 double mutant was unstable and produced fast-growing spontaneous sectors that were defective in plant infection. All spontaneous suppressor strains had mutations in FgSFL1, a transcription factor gene orthologous to SFL1 in yeast. Thirteen suppressor strains had non-sense mutations at Q501, three suppressor strains had frameshift mutations at W198, and five suppressor strains had mutations in the HSF binding domain of FgSfl1. Only one suppressor strain had both a non-synonymous mutation at H225 and a non-sense mutation at R490. We generated the SFL1 deletion mutant and found that it produced less than 2% of conidia than that of the wild-type strain PH-1. The sfl1 mutant was significantly reduced in the number of perithecia on carrot agar plates at 7 days post-fertilization (dpf). When incubated for more than 12 days, ascospore cirrhi were observed on the sfl1 mutant perithecia. The infection ability of the sfl1 deletion mutant was also obviously defective. Furthermore, we found that in addition to the S223 and S559 phosphorylation sites, FgSFL1 had another predicted phosphorylation site: T452. Interestingly, the S223 phosphorylation site was responsible for sexual reproduction, and the T452 phosphorylation site was responsible for growth and sexual reproduction. Only the S559 phosphorylation site was found to play an important role in conidiation, sexual reproduction, and infection. Overall, our results indicate that FgSFL1 and its conserved PKA phosphorylation sites are important for vegetative growth, conidiation, sexual reproduction, and pathogenesis in F. graminearum.

Download Full-text