Adaptative and Developmental Responses to Stress in Aspergillus nidulans

Abstract

Development in the ascomycete A. nidulans is principally determined by environmental signals. Adaptability to oxidative stimuli can derive in changes of growth patterns and /or the activation of sexual or asexual reproductive cycles but this model fungus might also respond to high osmotic or salt concentrations, the redox state, the availability and quantity of carbon or nitrogen sources and the degree or quality of illumination. Since each cell within the colony follows a single morphogenetic program at a time, all these environmental cues might be sensed and integrated into a limited number of intracellular signals which, finally, would activate the required morphogenetic program and repress the others. This signaling mainly occurs through stress response pathways. The present review aims to summarize the available knowledge on how these pathways transduce environmental stimuli to mediate morphological changes in Aspergillus nidulans.

Transcriptional Changes in the Transition from Vegetative Cells to Asexual Development in the Model Fungus Aspergillus nidulans

“…The loss of SrrA or SskA activity has been linked to decreased brlA levels (49). These previous observations strongly suggested that histidine kinases and components of the phosphorelay system are required to coordinate different stages of AD and the response to ambient stimuli (18).…”

“…Aspergillus nidulans is the reference organism in the study of fungal asexual development, also known as conidiation or conidiophore development (16)(17)(18)(19). The required morphological changes during conidiophore formation ( Fig.…”

Direct production of itaconic acid from liquefied corn starch by genetically engineered Aspergillus terreus

“…WT exhibited same trend as XH61-5 and XH86-8 in the two-stage processes, but different behaviour in the one-stage process: the glucose concentration gradually decreased during the initial period, then increased all the time (Additional file 11: Figure S10A, inset ). It appears that WT experienced the stages of carbon starvation and adaptive response to carbon starvation, which might induce complex alterations in the transcriptome, including the expression of genes encoding important elements of primary and secondary metabolism and programmed cell death processes, and complex well-regulated and energy-consuming physiological and morphological changes [24–26]. As a consequence, itaconate production may be adversely affected (Figure 2).…”

GmcA Is a Putative Glucose-Methanol-Choline Oxidoreductase Required for the Induction of Asexual Development in Aspergillus nidulans

“…Total protein extracts were obtained from mycelia of Δ flbB and its parental wild-type, TN02A3, strains and separated using two-dimensional protein electrophoreses (2D-PAGE). Since UDA genes are expressed during vegetative phase and all evidence indicates that they play a role at this stage in the signaling leading to conidiation [4], [5], protein extracts were obtained from vegetative cultures. From more than 200 spots detected in each 2D-PAGE gel, we selected 21 displaying differential intensity: 6 had a higher intensity in the Δ flb B strain protein extract (calculated WT/Δ flbB volume ratio of those spots, V WT /V Δ flbB , lower than 0.8 in all cases) while 15 had a lower intensity (V WT /V Δ flbB higher than 1.2).…”

“…This vegetative mode of growth is maintained under optimum nutritional and environmental conditions but the exposure of the mycelium to an air interphase [3], [7], light [8], [9] and/or nutrient starvation [10], [11] may activate different signaling pathways which transduce these signals into intracellular cues, ultimately resulting in the activation of brlA expression. brlA is the master gene for the production of asexual reproductive structures called conidiophores (see references within [4], [5], [12]). Generation of a conidiophore comprises the ordered formation of six well differentiated cell types: the foot-cell, the stalk, the vesicle, primary sterigmata (metulae), secondary sterigmata (phialides) and long chains of asexual spores (conidia) [13].…”