Culturing and Mating of Aspergillus fumigatus.

George D Ashton,Paul S Dyer

doi:10.1002/cpmc.87

Abstract

Aspergillus fumigatus is an opportunistic human fungal pathogen, capable of causing invasive aspergillosis in patients with compromised immune systems. The fungus was long considered a purely asexual organism. However, a sexual cycle was reported in 2009, with methods described to induce mating under laboratory conditions. The presence of a sexual cycle now offers a valuable tool for classical genetic analysis of the fungus, such as allowing determination of whether traits of interest are mono‐ or poly‐genic in nature. For example, the sexual cycle is currently being exploited to determine the genetic basis of traits of medical importance such as resistance to azole antifungals and virulence, and to characterize the genes involved. The sexual cycle can also be used to assess the possibility of gene flow between isolates. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.This unit describes protocols for culturing of A. fumigatus and for inducing sexual reproduction between compatible MAT1‐1 and MAT1‐2 isolates of the species. The unit also provides working methods for harvesting sexual structures, isolating single‐spore progeny and confirming whether sexual recombination has occurred. © The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Highlights

Aspergillus fumigatus is a very common environmental fungus, often isolated from air samples and from rotting vegetation
Follow-up work by Sugui et al (2011) led to the identification of “supermater” strains of A. fumigatus that were able to undergo the full sexual cycle within a shorter time period of three months, with ascospores present even after 4 weeks in certain crosses, and which were able to form relatively high numbers of cleistothecia with a wide range of isolates. This unit describes the protocol for inducing the sexual cycle of A. fumigatus under laboratory conditions by mating suitable strains, and methods for the collection and sorting of ascospore progeny, thereby providing the user with the tools to exploit this system for novel biomedical research
Incubating the A. fumigatus crosses using the barrage zone method described in Basic Protocol 3, allows large areas of interaction between the mating partners, which helps to maximize the number of cleistothecia produced

Summary

INTRODUCTION

Aspergillus fumigatus is a very common environmental fungus, often isolated from air samples and from rotting vegetation. Follow-up work by Sugui et al (2011) led to the identification of “supermater” strains of A. fumigatus that were able to undergo the full sexual cycle within a shorter time period of three months, with ascospores present even after 4 weeks in certain crosses, and which were able to form relatively high numbers of cleistothecia with a wide range of isolates This unit describes the protocol for inducing the sexual cycle of A. fumigatus under laboratory conditions by mating suitable strains, and methods for the collection and sorting of ascospore progeny, thereby providing the user with the tools to exploit this system for novel biomedical research.

The PCR cycle parameters are as follows:

CROSSING METHOD

Background

Literature Cited