18 Velvet Regulation of Fungal Development

Calvo, Ana M.; Lohmar, Jessica M.; Ibarra, Beatriz; Satterlee, Timothy

doi:10.1007/978-3-319-25844-7_18

Cited by 27 publications

(51 citation statements)

References 126 publications

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“…Additionally, we tested whether the effect of SUB1 might involve the function of VEL1, which was shown to regulate secondary metabolism in T. reesei (Bazafkan et al ., ) and other fungi (Calvo et al ., ). VEL1 promotes regulation of pks4 by ENV1, but does not regulate pks4 individually (Bazafkan et al ., ).…”

Section: Resultsmentioning

confidence: 97%

SUB1 has photoreceptor dependent and independent functions in sexual development and secondary metabolism in Trichoderma reesei

Bazafkan

Beier

Stappler

et al. 2017

Molecular Microbiology

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Light dependent processes are involved in the regulation of growth, development and enzyme production in Trichoderma reesei. The photoreceptors BLR1, BLR2 and ENV1 exert crucial functions in these processes. We analyzed the involvement of the transcription factor SUB1 in sexual development as well as secondary metabolism and its position in the light signaling cascade. SUB1 influences growth and in contrast to its homologue in N. crassa, SUB1 is not essential for fruiting body formation and male fertility in T. reesei, but required for female fertility. Accordingly, SUB1 is involved in the regulation of the pheromone system of T. reesei. Female sterility of mutants lacking env1 is rescued in triple mutants of blr1, blr2 and env1, but not in double mutants of these genes. Confrontation of strains lacking sub1 results in growth arrest prior to contact of the potential mating partners. This effect is at least in part due to altered secondary metabolite production. Additionally, together with BLR1 and BLR2, SUB1 is essential for spore pigmentation and transcription of pks4, and secondary metabolism is regulated by SUB1 in a light- and nutrient dependent manner. Our results hence indicate rewiring of several pathways targeted by SUB1 in T. reesei.

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Section: Resultsmentioning

confidence: 97%

SUB1 has photoreceptor dependent and independent functions in sexual development and secondary metabolism in Trichoderma reesei

Bazafkan

Beier

Stappler

et al. 2017

Molecular Microbiology

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“…Based on our results it is likely that the effect of rmtA on sclerotia could be affected by veA . In addition, veA has been shown to regulate other cellular processes in fungi, including conidiation and secondary metabolism [ 2 , 53 – 60 ]. Therefore, other roles of rmtA described in this study could also be veA -dependent, for example veA is a repressor of conidiation [ 58 , 60 ], and it is possible that the observed negative effect of rmtA on conidiation, as well as its positive effect on secondary metabolism, could also be influenced by the effect of rmtA on veA expression in A .…”

Section: Discussionmentioning

confidence: 99%

RmtA, a Putative Arginine Methyltransferase, Regulates Secondary Metabolism and Development in Aspergillus flavus

2016

Self Cite

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Aspergillus flavus colonizes numerous oil seed crops such as corn, peanuts, treenuts and cotton worldwide, contaminating them with aflatoxin and other harmful potent toxins. In the phylogenetically related model fungus Aspergillus nidulans, the methyltransferase, RmtA, has been described to be involved in epigenetics regulation through histone modification. Epigenetics regulation affects a variety of cellular processes, including morphogenesis and secondary metabolism. Our study shows that deletion of rmtA in A. flavus results in hyperconidiating colonies, indicating that rmtA is a repressor of asexual development in this fungus. The increase in conidiation in the absence of rmtA coincides with greater expression of brlA, abaA, and wetA compared to that in the wild type. Additionally, the rmtA deletion mutant presents a drastic reduction or loss of sclerotial production, while forced expression of this gene increased the ability of this fungus to generate these resistant structures, revealing rmtA as a positive regulator of sclerotial formation. Importantly, rmtA is also required for the production of aflatoxin B1 in A. flavus, affecting the expression of aflJ. Furthermore, biosynthesis of additional metabolites is also controlled by rmtA, indicating a broad regulatory output in the control of secondary metabolism. This study also revealed that rmtA positively regulates the expression of the global regulatory gene veA, which could contribute to mediate the effects of rmtA on development and secondary metabolism in this relevant opportunistic plant pathogen.

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“…The velvet complex mediates fungal developmental responses to environmental signals and is conserved in all filamentous Ascomycetes spp. examined to date (24,26).…”

Section: Importancementioning

confidence: 99%

Revitalization of a Forward Genetic Screen Identifies Three New Regulators of Fungal Secondary Metabolism in the Genus Aspergillus

Pfannenstiel

Zhao

Wortman

et al. 2017

mBio

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The study of aflatoxin in Aspergillus spp. has garnered the attention of many researchers due to aflatoxin's carcinogenic properties and frequency as a food and feed contaminant. Significant progress has been made by utilizing the model organism Aspergillus nidulans to characterize the regulation of sterigmatocystin (ST), the penultimate precursor of aflatoxin. A previous forward genetic screen identified 23 A. nidulans mutants involved in regulating ST production. Six mutants were characterized from this screen using classical mapping (five mutations in mcsA) and complementation with a cosmid library (one mutation in laeA). The remaining mutants were backcrossed and sequenced using Illumina and Ion Torrent sequencing platforms. All but one mutant contained one or more sequence variants in predicted open reading frames. Deletion of these genes resulted in identification of mutant alleles responsible for the loss of ST production in 12 of the 17 remaining mutants. Eight of these mutations were in genes already known to affect ST synthesis (laeA, mcsA, fluG, and stcA), while the remaining four mutations (in laeB, sntB, and hamI) were in previously uncharacterized genes not known to be involved in ST production. Deletion of laeB, sntB, and hamI in A. flavus results in loss of aflatoxin production, confirming that these regulators are conserved in the aflatoxigenic aspergilli. This report highlights the multifaceted regulatory mechanisms governing secondary metabolism in Aspergillus. Additionally, these data contribute to the increasing number of studies showing that forward genetic screens of fungi coupled with wholegenome resequencing is a robust and cost-effective technique.IMPORTANCE In a postgenomic world, reverse genetic approaches have displaced their forward genetic counterparts. The techniques used in forward genetics to identify loci of interest were typically very cumbersome and time-consuming, relying on Mendelian traits in model organisms. The current work was pursued not only to identify alleles involved in regulation of secondary metabolism but also to demonstrate a return to forward genetics to track phenotypes and to discover genetic pathways that could not be predicted through a reverse genetics approach. While identification of mutant alleles from whole-genome sequencing has been done before, here we illustrate the possibility of coupling this strategy with a genetic screen

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18 Velvet Regulation of Fungal Development

Cited by 27 publications

References 126 publications

SUB1 has photoreceptor dependent and independent functions in sexual development and secondary metabolism in Trichoderma reesei

SUB1 has photoreceptor dependent and independent functions in sexual development and secondary metabolism in Trichoderma reesei

RmtA, a Putative Arginine Methyltransferase, Regulates Secondary Metabolism and Development in Aspergillus flavus

Revitalization of a Forward Genetic Screen Identifies Three New Regulators of Fungal Secondary Metabolism in the Genus Aspergillus

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