Neurospora crassa, an orange bread mold discovered in 1843, was found in response to a reported contamination outbreak in French bakeries. Why does a fungus that caused an ‘outbreak’ elicit so much interest for current and future research? Geneticists and developmental biologists saw its potential as a model organism for several reasons:
- Typically haploid life cycle, with only a short diploid stage prior to meiosis
- Recessive mutations will show up in its phenotype
- Fast growth rate and simple nutritional requirements allowing for easy growth in vitro
- Orthodox Mendelian genetics
- Non-pathogenic
- More developmentally diverse than other fungi, such as yeasts
This simple bread mold serves as a model for filamentous fungi, accounting
for around 70% of the 250,000 species. The genome is 43 Mb organized into 7
chromosomes. Reproduction of this organism occurs through spore formation
resulting in the production of two kinds of spores:
- Conidia [asexual reproduction]
- Ascospores [sexual reproduction] confined to a narrow tube called the ascus
The genome was sequenced by Galagan, J. E., et al. in 2003 and consists of
38,639,769 DNA base pairs that encode for:
- 10,082 proteins
- 424 tRNAs
- 74 5S rRNAs
Neurospora crassa is described as a “paranoid organism,” meaning it employs
several protective mechanisms in order to effectively protect its genome. Many of
these mechanisms are the subject of study and allow the model behaviors performed by the organism such as:
- Post-transcriptional Modifications and Gene Silencing
- Photobiology and Circadian Rhythms
- Telomere Silencing
- Histone Modifications
- Mitochondrial Protein Imports
- Exogenous Protein Expression
References:
http://www.benchfly.com/blog/the-almighty-fungi-the-revolutionary-neurospora-crassa/
http://www.ncbi.nlm.nih.gov/pubmed/12712197
