Morphological and genetic characterisation of Hbr-2, a hyperbranching mutant of Aspergillus nidulans.

Stephen Memmott, Sarah Pollerman, and Geoffrey Turner.


Fungal morphology plays a major role in the fermentation industry as it affects the physiological state of the culture. This leads to consequences for both process conditions and final product yield. Fungal growth proceeds via the two basic mechanisms of hyphal elongation and the production of branches either at the hyphal tip or as lateral branches generated from intercalary compartments. The factors which control the production and frequency of branches are known to be both environmental and genetic. In order to discover underlying genetic components involved in the branching of Aspergillus nidulans, temperature sensitive, hyperbranching mutants were isolated and phenotypically characterised using branching frequency, septation and nuclear distribution measures. In addition genetic analysis was used to identify 10 loci affecting branching frequency. One such mutation, designated hbrA2, was chosen and the affected gene was isolated through functional complementation. A chromosome specific library and a co-transformation system was used to isolate a fragment complementing hbrA2. A sequence database search has given promising leads as to the function of hbrA2. Characterisation of this fragment will be described. Attempts are now being made to disrupt hbrA, and to place the gene under the control of a regulated promoter to study further the role of this gene in fungal growth.

abstract No: 

Fungal Genet. Newsl. 46 (Supl):

Full conference title: 

Fungal Genetics Conference 20th
    • Fungal Genetics Conference 20th (1999)