The calmodulin gene in Neurospora crassa is required for normal vegetative growth, ultraviolet survival, and sexual development

AbstractThe mating-type locus of Neurospora crassa regulates mating identity and entry into the sexual cycle. The mat A idiomorph encodes three genes, mat A-1, mat A-2, and mat A-3. Mutations in mat A-1 result in strains that have lost mating identity and vegetative incompatibility with mat a strains. A strain containing mutations in both mat A-2 and mat A-3 is able to mate, but forms few ascospores. In this study, we describe the isolation and characterization of a mutant deleted for mat (ΔmatA), as well as mutants in either mat A-2 or mat A-3. The ΔmatA strain is morphologically wild type during vegetative growth, but it is sterile and heterokaryon compatible with both mat A and mat a strains. The mat A-2 and mat A-3 mutants are also normal during vegetative growth, mate as a mat A strain, and produce abundant biparental asci in crosses with mat a, and are thus indistinguishable from a wild-type mat A strain. These data and the fact that the mat A-2 mat A-3 double mutant makes few asci with ascospores indicate that MAT A-2 and MAT A-3 are redundant and may function in the same pathway. Analysis of the expression of two genes (sdv-1 and sdv-4) in the various mat mutants suggests that the mat A polypeptides function in concert to regulate the expression of some sexual development genes.

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Multiple Functions of mfa-1, a Putative Pheromone Precursor Gene of Neurospora crassa

Eukaryotic Cell ◽

10.1128/ec.1.6.987-999.2002 ◽

2002 ◽

Vol 1 (6) ◽

pp. 987-999 ◽

Cited By ~ 56

Author(s):

Hyojeong Kim ◽

Robert L. Metzenberg ◽

Mary Anne Nelson

Keyword(s):

Neurospora Crassa ◽

Sexual Development ◽

Vegetative Growth ◽

Cysteine Residue ◽

Northern Analysis ◽

Mating Types ◽

Wild Type ◽

Minute Amount ◽

Female Sexual Development ◽

Ascospore Production

ABSTRACT A putative pheromone precursor gene of Neurospora crassa, mfa-1 (which encodes mating factor a-1), was identified as the most abundant clone in starved mycelial and perithecial cDNA libraries. Northern analysis demonstrated high mfa-1 expression in all mating type a tissues and suggested low expression levels in mat A tissues. The mfa-1 gene was expressed as an approximately 1.2-kb transcript predicted to encode a 24-residue peptide, followed by a long 3′ untranslated region (3′ UTR). The predicted MFA1 sequence showed 100% sequence identity to PPG2 of Sordaria macrospora and structural similarity (a carboxy-terminal CAAX motif) to many hydrophobic fungal pheromone precursors. Mutants with a disrupted open reading frame (ORF) in which the critical cysteine residue had been changed to a nonprenylatable residue, tyrosine (YAAX mutants), were isolated, as were mfa-1 mutants with intact ORFs but multiple mutations in the 3′ noncoding region (CAAX mutants). The 3′ UTR is required for the full range of mfa-1 gene activity. Both classes of mutants showed delayed and reduced vegetative growth (which was suppressed by supplementation with a minute amount [30 μM] of ornithine, citrulline, or arginine), as well as aberrant sexual development. When crossed as female parents to wild-type males, the CAAX and YAAX mutants showed greatly reduced ascospore production. No ascospores were produced in homozygous mfa-1 crosses. As males, YAAX mat a mutants were unable to attract wild-type mat A trichogynes (female-specific hyphae) or to initiate sexual development, while CAAX mat a mutants were able to mate and produce sexual progeny despite their inability to attract mat A trichogynes. In the mat A background, both CAAX and YAAX mutants showed normal male fertility but defective vegetative growth and aberrant female sexual development. Thus, the mfa-1 gene appears to have multiple roles in N. crassa development: (i) it encodes a hydrophobic pheromone with a putative farnesylated and carboxymethylated C-terminal cysteine residue, required by mat a to attract trichogynes of mat A; (ii) it is involved in female sexual development and ascospore production in both mating types; and (iii) it functions in vegetative growth of both mating types.

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Metabolism and Development during Conidial Germination in Response to a Carbon-Nitrogen-Rich Synthetic or a Natural Source of Nutrition inNeurospora crassa

mBio ◽

10.1128/mbio.00192-19 ◽

2019 ◽

Vol 10 (2) ◽

Cited By ~ 7

Author(s):

Zheng Wang ◽

Cristina Miguel-Rojas ◽

Francesc Lopez-Giraldez ◽

Oded Yarden ◽

Frances Trail ◽

...

Keyword(s):

Life History ◽

Sexual Reproduction ◽

Nitrogen Metabolism ◽

Asexual Reproduction ◽

Sexual Development ◽

Vegetative Growth ◽

Synthetic Medium ◽

Conidial Germination ◽

Content Type ◽

Genes Expression

ABSTRACTFungal spores germinate and undergo vegetative growth, leading to either asexual or sexual reproductive dispersal. Previous research has indicated that among developmental regulatory genes, expression is conserved across nutritional environments, whereas pathways for carbon and nitrogen metabolism appear highly responsive—perhaps to accommodate differential nutritive processing. To comprehensively investigate conidial germination and the adaptive life history decision-making underlying these two modes of reproduction, we profiled transcription ofNeurospora crassagerminating on two media: synthetic Bird medium, designed to promote asexual reproduction; and a natural maple sap medium, on which both asexual reproduction and sexual reproduction manifest. A later start to germination but faster development was observed on synthetic medium. Metabolic genes exhibited altered expression in response to nutrients—at least 34% of the genes in the genome were significantly downregulated during the first two stages of conidial germination on synthetic medium. Knockouts of genes exhibiting differential expression across development altered germination and growth rates, as well as in one case causing abnormal germination. A consensus Bayesian network of these genes indicated especially tight integration of environmental sensing, asexual and sexual development, and nitrogen metabolism on a natural medium, suggesting that in natural environments, a more dynamic and tentative balance of asexual and sexual development may be typical ofN. crassacolonies.IMPORTANCEOne of the most remarkable successes of life is its ability to flourish in response to temporally and spatially varying environments. Fungi occupy diverse ecosystems, and their sensitivity to these environmental changes often drives major fungal life history decisions, including the major switch from vegetative growth to asexual or sexual reproduction. Spore germination comprises the first and simplest stage of vegetative growth. We examined the dependence of this early life history on the nutritional environment using genome-wide transcriptomics. We demonstrated that for developmental regulatory genes, expression was generally conserved across nutritional environments, whereas metabolic gene expression was highly labile. The level of activation of developmental genes did depend on current nutrient conditions, as did the modularity of metabolic and developmental response network interactions. This knowledge is critical to the development of future technologies that could manipulate fungal growth for medical, agricultural, or industrial purposes.

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Global Gene Expression and Focused Knockout Analysis Reveals Genes Associated with Fungal Fruiting Body Development in Neurospora crassa

Eukaryotic Cell ◽

10.1128/ec.00248-13 ◽

2013 ◽

Vol 13 (1) ◽

pp. 154-169 ◽

Cited By ~ 38

Author(s):

Zheng Wang ◽

Francesc Lopez-Giraldez ◽

Nina Lehr ◽

Marta Farré ◽

Ralph Common ◽

...

Keyword(s):

Gene Expression ◽

Neurospora Crassa ◽

Sexual Development ◽

Fruiting Body ◽

Rna Silencing ◽

Global Gene Expression ◽

Gene Encoding ◽

Content Type ◽

Body Development ◽

Fruiting Body Development

ABSTRACTFungi can serve as highly tractable models for understanding genetic basis of sexual development in multicellular organisms. Applying a reverse-genetic approach to advance such a model, we used random and multitargeted primers to assay gene expression across perithecial development inNeurospora crassa. We found that functionally unclassified proteins accounted for most upregulated genes, whereas downregulated genes were enriched for diverse functions. Moreover, genes associated with developmental traits exhibited stage-specific peaks of expression. Expression increased significantly across sexual development for mating type genemat a-1and format A-1specific pheromone precursorccg-4. In addition, expression of a gene encoding a protein similar to zinc finger,stc1, was highly upregulated early in perithecial development, and a strain with a knockout of this gene exhibited arrest at the same developmental stage. A similar expression pattern was observed for genes in RNA silencing and signaling pathways, and strains with knockouts of these genes were also arrested at stages of perithecial development that paralleled their peak in expression. The observed stage specificity allowed us to correlate expression upregulation and developmental progression and to identify regulators of sexual development. Bayesian networks inferred from our expression data revealed previously known and new putative interactions between RNA silencing genes and pathways. Overall, our analysis provides a fine-scale transcriptomic landscape and novel inferences regarding the control of the multistage development process of sexual crossing and fruiting body development inN. crassa.

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G Protein α Subunit Genes Control Growth, Development, and Pathogenicity of Magnaporthe grisea

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.1997.10.9.1075 ◽

1997 ◽

Vol 10 (9) ◽

pp. 1075-1086 ◽

Cited By ~ 219

Author(s):

Shaohua Liu ◽

Ralph A. Dean

Keyword(s):

Neurospora Crassa ◽

G Protein ◽

Vegetative Growth ◽

Magnaporthe Grisea ◽

Cryphonectria Parasitica ◽

Appressorium Formation ◽

Α Subunit ◽

Targeted Deletion ◽

Control Growth ◽

G Protein Α Subunit

Three G protein α subunit genes have been cloned and characterized from Magnaporthe grisea: magA is very similar to CPG-2 of Cryphonectria parasitica; magB is virtually identical to CPG-1 of Cryphonectria parasitica, to gna1 of Neurospora crassa, and to fadA of Emericella nidulans; and magC is most similar to gna2 of Neurospora crassa. Homologous recombination resulting in targeted deletion of magA had no effect on vegetative growth, conidiation, or appressorium formation. Deletion of magC reduced conidiation, but did not affect vegetative growth or appressorium formation. However, disruption of magB significantly reduced vegetative growth, conidiation, and appressorium formation. magB¯ transformants, unlike magA¯ and magC¯ transformants, exhibited a reduced ability to infect and colonize susceptible rice leaves. G protein α subunit genes are required for M. grisea mating. magB¯ transformants failed to form perithecia, whereas magA¯ and magC¯ transformants did not produce mature asci. These results suggest that G protein α subunit genes are involved in signal transduction pathways in M. grisea that control vegetative growth, conidiation, conidium attachment, appressorium formation, mating, and pathogenicity.

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Changes in fatty acid composition of Neurospora crassa accompany sexual development and ascospore germination

Microbiology ◽

10.1099/00221287-144-7-1713 ◽

1998 ◽

Vol 144 (7) ◽

pp. 1713-1720 ◽

Cited By ~ 26

Author(s):

M. Goodrich-Tanrikulu ◽

K. Howe ◽

A. Stafford ◽

M. A. Nelson

Keyword(s):

Fatty Acid Composition ◽

Fatty Acid ◽

Neurospora Crassa ◽

Acid Composition ◽

Sexual Development ◽

Ascospore Germination

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The Predicted G-Protein-Coupled Receptor GPR-1 Is Required for Female Sexual Development in the Multicellular Fungus Neurospora crassa

Eukaryotic Cell ◽

10.1128/ec.00124-06 ◽

2006 ◽

Vol 5 (9) ◽

pp. 1503-1516 ◽

Cited By ~ 29

Author(s):

Svetlana Krystofova ◽

Katherine A. Borkovich

Keyword(s):

Neurospora Crassa ◽

G Protein ◽

Sexual Development ◽

Fluorescent Protein ◽

Protein Fusion ◽

Phenotypic Analysis ◽

Reproductive Structures ◽

Epistasis Analysis ◽

Green Fluorescent ◽

G Protein Coupled

ABSTRACTG-protein-coupled receptors (GPCRs) control important aspects of asexual and sexual development in eukaryotic organisms. We have identified a predicted GPCR in the filamentous fungusNeurospora crassawith similarity to cyclic AMP-receptor like GPCRs fromDictyostelium discoideumand GCR1 fromArabidopsis thaliana. Expression ofgpr-1is highest in female reproductive structures, and deletion ofgpr-1leads to defects during sexual development. Unfertilized female structures (protoperithecia) fromΔgpr-1strains are weakly pigmented, small, and submerged in the agar. The perithecia produced after fertilization have deformed beaks that lack ostioles, the openings through which ascospores are discharged. Localization studies using a GPR-1-green fluorescent protein fusion protein showed that GPR-1 is targeted to female reproductive structures. Genetic epistasis experiments with the three Gα genes were inconclusive due to the early block in mating exhibited by Δgna-1strains. Phenotypic analysis of mutants from a high-throughputN. crassaknockout project allowed identification of BEK-1, a homeodomain transcription factor that is a potential target of GPR-1. The perithecial defects ofΔbek-1strains are similar to those of theΔgpr-1strain, and epistasis analysis indicates thatbek-1could function downstream ofgpr-1during postfertilization events. The effect must be posttranscriptional, asbek-1transcript levels are not affected inΔgpr-1strains. The lack of ostioles inΔgpr-1and Δbek-1mutants has an undesirable effect on the ability to spread progeny (ascospores) by the normal ejection mechanism and would severely compromise the fitness of these strains in nature.

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