Action Spectrum between 260 and 800 Nanometers for the Photoinduction of Carotenoid Biosynthesis in <i>Neurospora crassa</i>

Fabo, Eward C. De; Harding, Roy W.; Shropshire, W.

doi:10.1104/pp.57.3.440

Cited by 121 publications

(40 citation statements)

References 26 publications

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“…In N. crassa, biochemical studies of the carotenoid biosynthetic pathway were carried out using wc and al mutants (9 (4,26,30). In contrast to these results, phytochrome has been proposed to be a photoreceptor for photoinduced carotenogenesis in another fungus Verticiium agaricinum (29).…”

Section: Discussionmentioning

confidence: 99%

Genetic Analysis of Phototropism of Neurospora crassa Perithecial Beaks Using White Collar and Albino Mutants

Harding

Melles²

1983

Plant Physiol.

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125

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Positive phototropism of perithecial beaks in the fungus Newrospora crassa has been demonstrated. The effect was shown to be mediated by blue Hght. When mutants (white collar-i and white collar-2) which are blocked In the Ught induction of enzymes in the carotenoid biosynthetic pathway were used as the protoperithecial parent in crosses, the resulting perithecial beaks did not show a phototropic response. However, when wild type, albino-i, albino-2, or albino-3 strains were used as the protoperithecial parent, phototropism occurred.The results show that both photoinduced carotenogenesis and phototropism in N. crassa are controlled by the white collar-i and white collar-2 loci. Thus, the sensory transduction pathways for the two photoresponses must have some steps in common. The results further support the proposal that the white collar strains are regulatory mutants blocked in the light induction process, whereas the albino-1, albino-2, and albino-3 strains can carry out light induction but have the albino phenotype because they are each defective for a different enzyme in the carotenoid biosynthetic pathway.Blue light-induced responses both in higher plants and microorganisms have been extensively studied (see reviews 27, 28). In the fungus Neurospora crassa, blue light has been shown to regulate a number of important processes including carotenoid biosynthesis (8, 24), photosuppression and phase shifting of the circadian rhythm of conidiation (5), photoinduction of protoperithecia formation (15), and under certain conditions promotion of conidiation (16). In Neurospora sitophila, positive phototropism of perithecial beaks (also referred to as perithecial necks) has also been demonstrated (1), but it was not determined whether this phototropic effect is a blue light response.Genetic studies have been carried out with N. crassa (9,17,19,20), Phycomyces blakesleeanus (2, 3, 18, 25), and Trichoderma (11) which are aimed at eventually identifying the blue light photoreceptor(s) (designated 'cryptochrome' [6]). In N. crassa, photoinduced carotenoid biosynthesis was investigated using wc and al mutants (9). The wc phenotype is defined as albino mycelia with normal pigmentation in the conidia, while the a) strains have a reduced level of carotenoid pigment in both the mycelia and conidia (21)(22)(23) proposal, it was predicted that the wc mutants may be blocked in other blue light-mediated responses in Neurospora (9). The present study was undertaken to test this hypothesis. Inasmuch as a phototropic response of N. sitophila perithecial beaks has been previously demonstrated (1), it was decided to determine whether such a response occurs in N. crassa.In the present study, phototropism of perithecial beaks in N. crassa was demonstrated. Furthermore, this response was blocked in perithecial beaks derived from crosses in which wc mutants were used as the protoperithecial (maternal) parent. No defect in phototropism was observed when the protoperithecial parent was wild type or al.MATERIALS AND METHODS Strains. Th...

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Section: Discussionmentioning

confidence: 99%

Genetic Analysis of Phototropism of Neurospora crassa Perithecial Beaks Using White Collar and Albino Mutants

Harding

Melles²

1983

Plant Physiol.

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125

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“…Although light signal transduction pathways have been primarily studied in plants (Chen et al, 2004), the filamentous fungus Neurospora crassa has become a preferred eukaryotic model to investigate pathways inducible by blue light. Early biochemical and photobiology studies reported that Neurospora is responsive only to blue light (Sargent and Briggs, 1967;DeFabo et al, 1976). Genes encoding putative red light photoreceptors have been recently discovered in the Neurospora genome (Galagan et al, 2003;Borkovich et al, 2004), but deletion of these genes does not affect any known photoresponses, leaving their function uncertain (Froehlich et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

TheNeurospora crassaWhite Collar-1 dependent Blue Light Response Requires Acetylation of Histone H3 Lysine 14 by NGF-1

Grimaldi¹,

Coiro²,

Filetici

et al. 2006

MBoC

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Blue light-induced transcription in Neurospora crassa is regulated by the White Collar-1 (WC-1) photoreceptor. We report that residue K14 of histone H3 associated with the light-inducible albino-3 (al-3) promoter becomes transiently acetylated after photoinduction. This acetylation depends on WC-1. The relevance of this chromatin modification was directly evaluated in vivo by construction of a Neurospora strain with a mutated histone H3 gene (hH3 K14Q ). This strain phenocopies a wc-1 blind mutant and shows a strong reduction of light-induced transcriptional activation of both al-3 and vivid (vvd), another light-inducible gene. We mutated Neurospora GCN Five (ngf-1), which encodes a homologue of the yeast HAT Gcn5p, to generate a strain impaired in H3 K14 acetylation and found that it was defective in photoinduction. Together, our findings reveal a direct link between histone modification and light signaling in Neurospora and contribute to the developing understanding of the molecular mechanisms operating in light-inducible gene activation.

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“…Although action spectra should provide, within limits, a reasonable representation of the absorption spectrum of the photoreceptor pigment, an action spectrum is insufficient for distinguishing between potential photoreceptor pigments with very similar absorption spectra (1,3,13). Moreover, the absorption spectrum for the photoreceptor pigment may depend strongly on its environment, but this environment is an unknown as long as the identity of the photoreceptor pigment itself is unknown.…”

Section: Introductionmentioning

confidence: 99%

Specific Inhibition of Phototropism in Corn Seedlings

Schmidt¹,

Hart²,

Filner³

et al. 1977

Plant Physiol.

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Geotropism was used as a control for the specifficity of potential inhibitors of phototropism by the coleoptiles of corn (Zea mays) seedlings. The compounds tested fall into three categories showing: (a) no inhibition of either phototropism or geotropism (KCI); (b) nonspecic inhibition of both phototropism and geotropism (KCN); and (c) specific inhibition of phototropism (KI, NaN3, and phenylacetic acid).Simuitaneous irradiation of coleoptiles with phototropically inert g4ht in addition to the phototropicafly active blue light also results in an inhibition of phototropism. Since azide, iodide, and phenylacetic acid are known to interact with flavins while a simultaneous irradiation with a phototropicafly inert light may depopulate the first triplet state of flavins, these data support the hypothesis that the photoreceptor pigment for phototropism in corn is a flavin.The identification of the photoreceptor pigment controlling phototropism has in general not progressed beyond a description of action spectra for the physiological response. Although action spectra should provide, within limits, a reasonable representation of the absorption spectrum of the photoreceptor pigment, an action spectrum is insufficient for distinguishing between potential photoreceptor pigments with very similar absorption spectra (1,3,13). Moreover, the absorption spectrum for the photoreceptor pigment may depend strongly on its environment, but this environment is an unknown as long as the identity of the photoreceptor pigment itself is unknown.Because of these inadequacies of action spectra as the major criterion for the photoreceptor pigment, we have searched for other criteria to identify the photoreceptor pigment for phototropism. We report here the results of experiments on the effects of potential inhibitors on phototropism and geotropism, pursuing the observation of Hart and Filner (6) H20. The trays were placed in large closed black boxes to keep humidity constant and the boxes were kept in a constant temperature, controlled humidity, darkroom. Only that 20% of the seedlings with straight shoots were used. The seedlings were prepared for the experiments under dim (<1 ,w cm-2) 540 nm (10 nm half-bandwidth) safelight. Each seedling was placed in a 50-ml test tube with the root system in a bathing solution and with 3 cm of the shoot projecting through a hole in a cork stopper inserted in the opening of the test tube. The seedlings were incubated with the roots immersed in a solution of the potential inhibitor at pH 7 for 1 hr before application of the test stimulus (light or gravity). All experiments were conducted at22 + 1 C.To test for geotropism, seedlings were turned horizontal for 1 hr. The geotropic response was then permitted to develop in the vertical position for 4 hr. Phototropism was induced for 5 hr with 2 ,uw cm-2 blue (440 nm) light from a 40 w Unitron incandescent lamp through an interference filter with a 10 nm half-bandwidth. The phototropic response to this intensity of light probably falls into the ...

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Action Spectrum between 260 and 800 Nanometers for the Photoinduction of Carotenoid Biosynthesis in Neurospora crassa

Cited by 121 publications

References 26 publications

Genetic Analysis of Phototropism of Neurospora crassa Perithecial Beaks Using White Collar and Albino Mutants

Genetic Analysis of Phototropism of Neurospora crassa Perithecial Beaks Using White Collar and Albino Mutants

TheNeurospora crassaWhite Collar-1 dependent Blue Light Response Requires Acetylation of Histone H3 Lysine 14 by NGF-1

Specific Inhibition of Phototropism in Corn Seedlings

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