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Life cycle of Neurospora crassa. Depending on environmental conditions, the vegetative mycelium can undergo the asexual sporulation processes (macroconidiation and microconidiation). It can enter the sexual cycle by forming protoperithecia. Upon fertilization, they initiate development leading to the production of meiotically derived ascospores. Blue light inputs are shown by arrows.
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In the ascomycete fungus Neurospora crassa blue-violet light controls the expression of genes responsible for differentiation of reproductive structures, synthesis of secondary metabolites, and the circadian oscillator activity. A major photoreceptor in Neurospora cells is WCC, a heterodimeric complex formed by the PAS-domain-containing polypeptide...
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... fusion among hyphal filaments produces a complex hyphal network (the mycelium) [29] and promotes the formation of heterokaryons in which multiple genomes can contribute to the metabolism of a single mycelium. Specialized aerial hyphae are differentiated from vegetative hyphae in response to nutrient deprivation, desiccation, or various stresses, and these form chains of asexual spores (the multinucleate macroconidia) for dispersal [30] ( Figure 1). The timing of macroconidiation is controlled by a circadian rhythm, which in turn is modulated by exposure to blue light. ...Context 2
... perithecium comprises 200-400 asci, each containing eight oval mononuclear haploid ascospores. During germination of ascospores, hyphae of vegetative mycelium develop, as in the case of conidia (Figure 1). The genome of Neurospora, comprising 42.9 million bp, has been decoded [35]. ...Context 3
... effect of light is manifested at different stages of the Neurospora life cycle (Figures 1 and 2). Light promotes changes in the electrophysiological parameters of hyphae: the input resistance increases, followed by hyperpolarization of the cytoplasmic membrane [36]. ...Context 4
... carbon starvation, in nitrogen starvation light inhibits conidiation and simultane- ously stimulates the formation of protoperithecia [46]. In other words, under these conditions light determines the selection of either the sexual or asexual development pathway ( Figure 1). Perithecia occurring during the sexual cycle are also sensitive to light, which induces their polarity (i.e., formation of a so-called beak at one end of the perithe- cium, which, in turns, exhibits positive phototropism) [14] ( Figure 2). ...Citations
... The fungus N. crassa possesses a blue light receptor gene, WC-1, which forms heterodimers (WCC) with WC-2. These dimers are active under white and blue light conditions, playing a crucial role in the organism's perception of and response to such light, notably in triggering carotenoid production [30]. Additionally, N. crassa features another blue light receptor, VIVID, which is minimally expressed in darkness and becomes active in light [31]. ...
Light regulation is critical in fungal growth, development, morphogenesis, secondary metabolism, and the biological clock. The fungus Elsinoë arachidis is known to produce the mycotoxin Elsinochrome (ESC), a key factor contributing to its pathogenicity, under light conditions. Although previous studies have predominantly focused on the light-induced production of ESC and its biosynthetic pathways, the detailed mechanisms underlying this process remain largely unexplored. This study explores the influence of light on ESC production and gene expression in E. arachidis. Under white light exposure for 28 days, the ESC yield was observed to reach 33.22 nmol/plug. Through transcriptome analysis, 5925 genes were identified as differentially expressed between dark and white light conditions, highlighting the significant impact of light on gene expression. Bioinformatics identified specific light-regulated genes, including eight photoreceptor genes, five global regulatory factors, and a cluster of 12 genes directly involved in the ESC biosynthesis, with expression trends confirmed by RT-qPCR. In conclusion, the study reveals the substantial alteration in gene expression associated with ESC biosynthesis under white light and identifies potential candidates for in-depth functional analysis. These findings advance understanding of ESC biosynthesis regulation and suggest new strategies for fungal pathogenicity control.
... Reactive oxygen species (ROS) are essential signaling molecules in most organisms in response to stress (Waszczak et al., 2018). For example, stress-related genes are activated by light in Aspergillus nidulans (Elramli et al., 2019), and ROS affect photomorphogenesis in Neurospora crassa (Belozerskaya et al., 2012). Autophagy, from the Greek words "auto" (self) and "phagy" (to eat), is a highly regulated cellular degradation and recycling process that is conserved from yeast to higher eukaryotes (Sibirny, 2011). ...
Lentinula edodes (Berk.) Pegler, the shiitake mushroom, is one of the most important mushrooms in the global mushroom industry. Although mycelium post ripeness and brown film (BF) formation are crucial for fruiting body initiation, the underlying molecular mechanisms of BF formation are largely unknown. In this study, proteomic quantification (relative and absolute) and metabolomic profiling of L. edodes were performed using isobaric tags and gas chromatography-mass spectroscopy, respectively. A total of 2,474 proteins were identified, which included 239 differentially expressed proteins. Notably, several proteins associated with autophagy were upregulated, including RPD3, TOR1, VAC8, VPS1, and VPS27. Transmission electron microscopy also indicated that autophagy occurred in post ripeness and BF formation. In time-dependent analysis of the metabolome, metabolites associated with oxidative stress and autophagy changed significantly, including mannitol, trehalose, myo-inositol, glucose, leucine, valine, glutamine, and 4-aminobutyric acid. Thus, oxidative stress and autophagy were important processes in post ripeness and BF formation in L. edodes , and new insights were gained into molecular mechanisms at proteome and metabolome levels.
... Moreover, WC1 expression was also lower in the CRY1 disruptant. In Neurospora crassa, the white-collar complex (WCC), a protein complex formed by WC1 and WC2 proteins known as the primary photoreceptor system for blue light, promoted carotenoid biosynthesis by light irradiation (He et al. 2002;Iigusa, Yoshida and Hasunuma 2005;Belozerskaya et al. 2012). But other reports mentioned Cryptochrome DASH (encoded by CRY1), which has been identified as a blue light receptor plays the role in promoting the carotenoid production (Ahmad et al. 1998;Facella et al. 2006;Froehlich et al. 2010;Yu et al. 2010;Castrillo and Avalos 2015). ...
Light stimulates carotenoid production in an oleaginous yeast Rhodosporidium toruloides NBRC 10032 by promoting carotenoid biosynthesis genes. These genes undergo two-step of transcriptional activation. The potential light regulator, Cryptochrome DASH (CRY1), has been suggested to contribute to this mechanism. In this study, based on KU70 (a component of non-homologous end joining (NHEJ)) disrupting background, CRY1 disruptant was constructed to clarify CRY1 function. From analysis of CRY1 disruptant, it was suggested that CRY1 has the activation role of the carotenogenic gene expression. To obtain further insights into the light response, mutants varying carotenoid production were generated. Through analysis of mutants, the existence of the control two-step gene activation was proposed. In addition, our data analysis showed the strong possibility that R. toruloides NBRC 10032 is a homo-diploid strain.
... Only three fungal species, i.e., T. inflatum, S. lanosoniveum, and L. aphanocladii, did not respond to light as their conidia produced under illumination exhibited similar tolerances to stress as conidia produced in the dark (Table 2). Connection between light and stress signaling has been found in the fungal species Alternaria alternata (Igbalajobi et al., 2019), Aspergillus nidulans (Yu et al., 2016), Aspergillus fumigatus (Fuller et al., 2013), B. bassiana (Qiu et al., 2014;Tong et al., 2018), Botrytis cinerea (Canessa et al., 2013), Colletotrichum acutatum (de Menezes et al., 2015;Costa et al., 2021), C. neoformans (Verma and Idnurm, 2013), Fusarium fujikuroi (Costa et al., 2021), Magnaporthe oryzae (Aver'yanov et al., 2014), M. robertsii (Rangel et al., , 2015bDias et al., 2020), M. acridum (Brancini et al., 2016(Brancini et al., , 2019, N. crassa (Belozerskaya et al., 2012;de Paula et al., 2008;Lamb et al., 2012;Vitalini et al., 2007), and Trichoderma atroviride (Esquivel-Naranjo et al., 2016;Moreno-Ruiz et al., 2020). Therefore, this study adds five more fungal species to this list e A. aleyrodis, C. fumosorosea, M. anisopliae, M. brunneum, and T. cylindrosporum e which respond to the light by producing conidia more tolerant to various stresses ( Table 2). ...
Light is an important signal for fungi in the environment and induces many genes with roles in stress and virulence responses. Conidia of the entomopathogenic fungi Aschersonia aleyrodis, Beauveria bassiana, Cordyceps fumosorosea, Lecanicillium aphanocladii, Metarhizium anisopliae, Metarhizium brunneum, Metarhizium robertsii, Simplicillium lanosoniveum, Tolypocladium cylindrosporum, and Tolypocladium inflatum were produced on potato dextrose agar (PDA) medium under continuous white light, on PDA medium in the dark, or under nutritional stress (= Czapek medium without sucrose = MM) in the dark. The conidial tolerance of these species produced under these different conditions were evaluated in relation to heat stress, oxidative stress (menadione), osmotic stress (KCl), UV radiation, and genotoxic stress caused by 4-nitroquinoline 1-oxide (4-NQO). Several fungal species demonstrated greater stress tolerance when conidia were produced under white light than in the dark; for instance white light induced higher tolerance of A. aleyrodis to KCl and 4-NQO; B. bassiana to KCl and 4-NQO; C. fumosorosea to UV radiation; M. anisopliae to heat and menadione; M. brunneum to menadione, KCl, UV radiation, and 4-NQO; M. robertsii to heat, menadione, KCl, and UV radiation; and T. cylindrosporum to menadione and KCl. However, conidia of L. aphanocladii, S. lanosoniveum, and T. inflatum produced under white light exhibited similar tolerance as conidia produced in the dark. When conidia were produced on MM, a much stronger stress tolerance was found for B. bassiana to menadione, KCl, UV radiation, and 4-NQO; C. fumosorosea to KCl and 4-NQO; Metarhizium species to heat, menadione, KCl, and UV radiation; T. cylindrosporum to menadione and UV radiation; and T. inflatum to heat and UV radiation. Again, conidia of L. aphanocladii and S. lanosoniveum produced on MM had similar tolerance to conidia produced on PDA medium in the dark. Therefore, white light is an important factor that induces higher stress tolerance in some insect-pathogenic fungi, but growth in nutritional stress always provides in conidia with stronger stress tolerance than conidia produced under white light.
... It is widely known as the primary photoreceptor system for blue light [18]. The protein complex, WC-1 and WC-2 also are involved in the promotion of carotenoid biosynthesis by light irradiation [45][46][47]. Cryptochrome DASH has recently been reported to qRT-PCR analyses for genes HMGS, HMGR, MVAK2, MVAKD, IDI, FDPS, GGPSI, CAR2 and CAR1 in RNA samples grown in the dark (black) and exposed to light (white) for the time indicated (h). ...
The oleaginous yeast Rhodosporodium toruloides is receiving widespread attention as an alternative energy source for biofuels due to its unicellular nature, high growth rate and because it can be fermented on a large-scale. In this study, R. toruloides was cultured under both light and dark conditions in order to understand the light response involved in lipid and carotenoid biosynthesis. Our results from phenotype and gene expression analysis showed that R. toruloides responded to light by producing darker pigmentation with an associated increase in carotenoid production. Whilst there was no observable difference in lipid production, slight changes in the fatty acid composition were recorded. Furthermore, a two-step response was found in three genes (GGPSI, CAR1, and CAR2) under light conditions and the expression of the gene encoding the photoreceptor CRY1 was similarly affected.
... Transcriptional analysis of structural genes of β-carotene biosynthesis (carB and carRP) showed increased mRNA levels in response to light, in accordance with the improved carotene content [7]. In N. crassa, the most prominent carotenogenic synthesis by light was observed [24,25]. Upon exposure to blue light, the genes involved in carotene production were upregulated, leading to fast accumulation of orange-color carotene pigment [26] as compared to mycelia that were grown in the dark which had only trace of carotenes. ...
... Similarly in WJ11, 2.2-fold increase in pigment accumulation was observed. This was consistent with the findings of previous studies that continuous illumination triggered pigment accumulation enormously as compared to fungal culture grown in dark [24,25]. Initial studies about photo-induction of carotenogenesis revealed the same trend in Fusarium aquaeductuum, i.e., exposure to light-induced a gradual carotenoid accumulation, reaching its maximum level at about 12 h after which synthesis kept increasing gradually for at least three days when the culture was maintained under continuous illumination [34]. ...
... The pH was maintained at 6.0 by auto-addition of 2 M NaOH. Sampling was done at different time intervals e.g., 3,6,9,12,24,48,72, and 96 h. ...
Carotenoids are natural potent antioxidants and free radical scavengers which are able to modulate the pathogenesis of some cancers and heart diseases in human, indicating their importance in being provided through the diet. Mucor circinelloides accumulates β-carotene as the main carotenoid compound and has been used as a model organism in carotenogenic studies. In the present study, the potential of two M. circinelloides strains to accumulate β-carotene was investigated under light and dark conditions. The results, which were quantitated by HPLC, showed that CBS 277.49 accumulated higher pigment in comparison to WJ11 under both conditions. Continuous illumination triggered the pigment accumulation up to 2.7-fold in strain CBS 277.49 and 2.2-fold in strain WJ11 in comparison to dark. The mRNA analysis of the four key genes involved in isoprenoid pathway by RT-qPCR showed higher transcriptional levels in CBS 277.49 as compared to WJ11, indicating that the pigment production metabolic machinery is more active in CBS 277.49 strain. A new scope for further research was established by this work for improved β-carotene production in the high producing strain CBS 277.49.
... In fungi, like in many other aerobic organisms, one of the first cell detoxification responses is against ROS accumulation, which includes an increase in the activities of the principal antioxidant enzymes, such as superoxide dismutase (SOD) and catalase (CAT), which play key roles in ROS scavenging [50][51][52] . Herein, we reported that CAT activity was higher in the 1/46 mutant strain than FB2 parental strain. ...
Ustilago maydis is a dimorphic fungus that has emerged as a model organism for the study of fungal phytopathogenicity and RNA biology. In a previous study, we isolated the U. maydis UmRrm75 gene. The deletion of the UmRrm75 gene affected morphogenesis and pathogenicity. UmRrm75 gene encodes a protein containing three RNA recognition motifs. Here we determined that UmRrm75 has chaperone activity in Escherichia coli using the transcription anti-termination assay. Subsequently, we analyzed the growth of ΔUmRrm75 mutants at 15 °C and 37 °C, observing that mutant strains had reduced growth in comparison to parental strains. UmRrm75 gene expression was induced under these non-optimal temperatures. ΔUmRrm75 mutant colonies displayed a dark-brown color at 28 °C, which was confirmed to be melanin based on spectroscopic analysis and spectrometric data. Furthermore, ΔUmRrm75 mutant strains showed the presence of peroxisomes, and increased H2O2 levels, even at 28 °C. The ΔUmRrm75 mutant strains displayed a higher expression of redox-sensor UmYap1 gene and increased catalase activity than the parental strains. Our data show that deletion of the UmRrm75 gene results in higher levels of H2O2, increased melanin content, and abiotic stress sensitivity.
... A single 68-bp intron was confirmed by comparing the sequences between genomic DNA and cDNA. The predicted domain structures of the SfWC-1 protein contained an LOV domain, two PAS domains, and a GATA-type zinc finger DNA binding domain, which might support the light-sensing function of SfWC-1 as a white collar-1 blue-light photoreceptor similar to N. crassa WC-1 ( Fig. 2A) (12,15,45). ...
... The Sfwc-1 photoreceptor gene might participate to regulate genes involved in the carotenoid biosynthesis pathway. In Neurospora, albino genes (al-1, al-2, and al-3) encoding enzymes responsible for carotenoid biosynthesis are light induced in hyphae and regulated by WCC (15,47). To better understand the role of Sfwc-1 in the carotenoid biosynthesis pathway, we analyzed the mRNA expression profiles of putative genes involved in carotenogenesis, Sfal-1 (SF_NCU00552), Sfal-2 (SF_NCU00585), Sfal-3 (SF_NCU01427), and Sfcao-2 (SF_ NCU11424) in the wild type and in the Sfwc-1 (⌬lov) mutant under light induction. ...
... These findings agreed with the light-induced carotenoid pigmentation of mycelia found in the wild type and undetectable accumulation of carotenoid pigment in Sfwc-1 (⌬lov) mycelia (Fig. S1). Hence, carotenoid biosynthesis genes in S. fimicola were light induced via Sfwc-1 regulation, similar to that found in N. crassa (15,49). ...
Sordaria sp. has been a model for study of fruiting-body differentiation in fungi. Several environmental factors, including light, affect cellular and morphological changes during multicellular tissue development. Here, we created a light-oxygen-voltage-sensing (LOV) domain-deleted Sfwc-1 mutant to study blue-light photoresponses in Sordaria fimicola . Phototropism and rhythmic zonation of perithecia were defective in the Sfwc-1 ⁽ Δlov ⁾ mutant. Moreover, fruiting-body development in the mutant was reduced and also significantly delayed. Gene expression analysis and subcellular localization study further revealed the light-induced differential gene expression and cellular responses upon light stimulation in S. fimicola .
... Multistress responses in A. alternata are dependent on FphA, LreA, and HogA. In N. crassa, T. atroviride, B. cinerea, A. nidulans, and A. fumigatus, links between light and stress signaling were shown (28,38,50,59,60). In order to assign a role for FphA, LreA, and HogA in the modulation of stress responses in A. alternata, we investigated the effect of the inactivation of these genes on medium supplemented with osmotic, oxidative, and cell wall-degrading agents incubated at 28°C for 4 days in the dark. ...
Light controls many processes in filamentous fungi. The study of light regulation in a number of model organisms revealed an unexpected complexity. Although the molecular components for light sensing appear to be widely conserved in fungal genomes, the regulatory circuits and the sensitivity of certain species toward specific wavelengths seem different. In N. crassa , most light responses are triggered by blue light, whereas in A. nidulans , red light plays a dominant role. In Alternaria alternata , both blue and red light appear to be important. In A. alternata , photoreceptors control morphogenetic pathways, the homeostasis of reactive oxygen species, and the production of secondary metabolites. On the other hand, high-osmolarity sensing required FphA and LreA, indicating a sophisticated cross talk between light and stress signaling.
... In addition, it was reported that the oxidative stress was accompanied by severe metabolic changes directed towards a decrease in primary metabolites (acetate, glucose) and synthesis of compounds participating in cell protection; e.g. carotenoids, melanins, proline, and polyols [30,31]. The present study indicated that the catalytic activity of Fe 2+ was better observed in the case of A. niger and P. citrinum spores compared to non-catalytic hydrogen peroxide. ...
The presence of fungi in water systems represents a threat to human health. Hydrogen peroxide is known for its disinfecting properties and easy decomposition to water and oxygen. Its activity can be enhanced by the addition of iron as a catalyst, a reagent known as Fentonʼs reagent. In the present study, different Fenton concentrations were investigated on the spores of Aspergillus flavus, Aspergillus niger and Penicillium citrinum at different time intervals. The results indicate that complete inactivation of spores was noticed after 60 min of exposure to both 2 and 3% H2O2 catalyzed by 0.025 g Fe²⁺/100 ml for A. niger, and 3% H2O2 catalysed by 0.075 g Fe²⁺/100 ml for P. citrinum. The activity of two antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), was determined in mycelial mat harvested after 7 days. Their activities were either highly increased or reached their minimum values prior to inactivation of spores.
