Abstract
Establishment of a fungal infection due to Aspergillus fumigatus relies on the efficient germination of the airborne conidia once they penetrate the respiratory tract. However, the features of conidial germination have been poorly explored and understood in this fungal species as well as in other species of filamentous fungi. We show here that the germination of A. fumigatus is asynchronous. If the nutritional environment and extensive gene deletions can modify the germination parameters for A. fumigatus, the asynchrony is maintained in all germinative conditions tested. Even though the causes for this asynchrony of conidial germination remain unknown, asynchrony is essential for the completion of the biological cycle of this filamentous fungus.
Highlights
Aspergillus fumigatus is a saprotrophic fungus which lives in the soil in decaying vegetal material and upon inhalation of airborne conidia can cause life-threatening infections.Conidia are ubiquitous in the air and continuously transported through the air current.Encountering an aqueous nutritive environment leads to conidial germination
Transcriptome analyses have shown that active transcripts from one third of the genome are present in conidia
These data suggest that resting conidia, resembling a time bomb, are ready to explode and germinate as soon as they encounter a favorable aqueous nutritive environment without any need for de novo transcription to initiate germination [2,48]
Summary
Aspergillus fumigatus is a saprotrophic fungus which lives in the soil in decaying vegetal material and upon inhalation of airborne conidia can cause life-threatening infections.Conidia are ubiquitous in the air and continuously transported through the air current.Encountering an aqueous nutritive environment leads to conidial germination. Germination can be classically divided into three stages. A lag phase occurs without any morphological modification but with an active intracellular expression of genes [1,2], preparing the synthesis of protein necessary for germination but not requiring de novo RNA synthesis. The second stage is the isodiametral growth of germinating conidia consecutive to an intracellular increase in osmotic pressure. The third stage corresponds to a polarized growth with the formation of a germ tube [3,4] after the first mitosis. If the association between the polarized growth and mitotic events has been well established in Aspergillus [4,5,6], the characterization of the early stages of germination has been poorly understood. Even though an Aspergillus colony originates from one conidium with a single nucleus, heterogeneity in the physiological activities in different regions of a colony or in different hyphal compartments within a single hyphae has been repeatedly noticed [7]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
