Conidiation of phytopathogenic fungi is a key developmental process that plays a central role in their life cycles and in epidemics. However, there is little information on conidiation-induced molecular changes in the rice blast fungus Magnaporthe oryzae. As a first step to understand conidiogenesis in this fungus, we measured genome-wide gene expression profiles during conidiation using a whol...

A quantitative survey has been made of conidiation mutants in Aspergillus nidulans. Conidiation mutants were 6 to I 3 times more numerous than auxotrophic mutants, but growth tests showed that the mutant defect in 85 % of the conidiation mutants was not confined to conidiation. The number of loci specifically involved in conidiation was estimated to be 45 to 150. Mutants were classified accordi...

Asexual development (conidiation) in the filamentous fungus Aspergillus nidulans is governed by orchestrated gene expression. The three key negative regulators of conidiation SfgA, VosA, and NsdD act at different control point in the developmental genetic cascade. Here, we have revealed that NsdD is a key repressor affecting the quantity of asexual spores in Aspergillus. Moreover, nullifying bo...

The asexual spore is one of the most crucial factors contributing to the fecundity and fitness of filamentous fungi. Although the developmental activator FluG was shown to be necessary for activation of asexual sporulation (conidiation) and production of the carcinogenic mycotoxin sterigmatocystin (ST) in the model filamentous fungus Aspergillus nidulans, the molecular mechanisms underlying the...

Asexual development (conidiation) of the filamentous fungus Aspergillus nidulans occurs via balanced activities of multiple positive and negative regulators. For instance, FluG (+) and SfgA (-) govern upstream regulation of the developmental switch, and BrlA (+) and VosA (-) control the progression and completion of conidiation. To identify negative regulators of conidiation downstream of FluG-...

Using an insertional mutagenesis approach, a series of Neurospora crassa mutants affected in the ability to control entry into the conidiation developmental program were isolated. One such mutant, GTH16-T4, was found to lack normal vegetative hyphae and to undergo constitutive conidiation. The affected gene has been named nrc-1, for nonrepressible conidiation gene #1. The nrc-1 gene was cloned ...

The opportunistic human pathogen Aspergillus fumigatus produces a large quantity of asexual spores (conidia), which are the primary agent causing invasive aspergillosis in immunocompromised patients. We investigated the mechanisms controlling asexual sporulation (conidiation) in A. fumigatus via examining functions of four key regulators, GpaA (Galpha), AfFlbA (RGS), AfFluG, and AfBrlA, previou...

Background:  Dermatophytes are common causes of cutaneous infections in humans and animals, which mostly reproduce by an asexual process. Such types of reproduction in many filamentous fungi are usually regulated by brlA, abaA, and wetA genes. The presence of these genes in dermatophytes was investigated.  Materials & Methods:   Conidiation genes represented by brlA, abaA, and wetA were dete...

Efforts to significantly perturb the timing mechanism, and thus the period, of the rhythm responsible for circadian conidiation in bd, a strain of Neurospora crassa, by altering the medium composition have been unsuccessful. Various salt solutions, sugars, and amino acids do, however, have pronounced effects on growth and conidiation, and thus on the expression and persistence of rhythmicity.Ae...

In the filamentous fungus Aspergillus oryzae, there has been no report on photoreaction. Here we investigated the effect of light in A. oryzae and found that conidiation was repressed by white light. This reaction is contrary to that of other Aspergilli, which show abundant conidiation under light. Moreover, red light also caused reduced conidiation. Genome sequencing of A. oryzae indicated the...