Germling fusion via conidial anastomosis tubes in the grey mould Botrytis cinerea requires NADPH oxidase activity

Roca, M. Gabriela; Weichert, Martin; Siegmund, Ulrike; Tudzynski, Paul; Fleißner, André

doi:10.1016/j.funbio.2011.12.007

Cited by 77 publications

(71 citation statements)

References 44 publications

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“…For this reason, we cannot eliminate the possibility that the essential function of the E. festucae so gene in maintaining mutualistic symbiosis may be independent of its role in hyphal anastomosis. Nevertheless, it should be noted that E. festucae strains lacking any one of the components of the NADPH oxidase complex (40)(41)(42), whose orthologs are essential for hyphal anastomosis (17,31,35), also showed a defect in the establishment/maintenance of symbiosis similar to that in our E. festucae ⌬so mutant strains. Thus, it seems likely that the lack of hyphal anastomosis is at least partly responsible for disrupting mutualism, leading to the endophytemediated death of the host plant.…”

Section: Discussionsupporting

confidence: 59%

Deletion of the Fungal Gene soft Disrupts Mutualistic Symbiosis between the Grass Endophyte Epichloë festucae and the Host Plant

et al. 2012

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Hyphal anastomosis, or vegetative hyphal fusion, establishes the interconnection of individual hyphal strands into an integrated network of a fungal mycelium. In contrast to recent advances in the understanding of the molecular basis for hyphal anastomosis, knowledge of the physiological role of hyphal anastomosis in the natural habitats of filamentous fungi is still very limited. To investigate the role of hyphal anastomosis in fungal endophyte-plant interactions, we generated mutant strains lacking the Epichloë festucae soft (so) gene, an ortholog of the hyphal anastomosis gene so in the endophytic fungus E. festucae. The E. festucae ⌬so mutant strains grew similarly to the wild-type strain in culture but with reduced aerial hyphae and completely lacked hyphal anastomosis. The most striking phenotype of the E. festucae ⌬so mutant strain was that it failed to establish a mutualistic symbiosis with the tall fescue plant host (Lolium arundinaceum); instead, it killed the host plant within 2 months after the initial infection. Microscopic examination revealed that the death of the tall fescue plant host was associated with the distortion and disorganization of plant cells. This study suggests that hyphal anastomosis may have an important role in the establishment/ maintenance of fungal endophyte-host plant mutualistic symbiosis.

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Section: Discussionsupporting

confidence: 59%

Deletion of the Fungal Gene soft Disrupts Mutualistic Symbiosis between the Grass Endophyte Epichloë festucae and the Host Plant

et al. 2012

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“…This is similar to the reports that the PD medium suppresses CAT formation in other filamentous fungi. 15,16) DPY medium had an inhibitory effect on hyphal fusion, and its components polypeptone and yeast extract also caused an inhibition. Polypeptone is probably recognized as a nitrogen source that can be easily assimilated, which decreases the hyphal fusion efficiency like ammonium and glutamine.…”

Section: Discussionmentioning

confidence: 99%

Establishment of a new method to quantitatively evaluate hyphal fusion ability in Aspergillus oryzae

Tsukasaki

Maruyama

Kitamoto

2014

Bioscience, Biotechnology, and Biochemistry

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Hyphal fusion is involved in the formation of an interconnected colony in filamentous fungi, and it is the first process in sexual/parasexual reproduction. However, it was difficult to evaluate hyphal fusion efficiency due to the low frequency in Aspergillus oryzae in spite of its industrial significance. Here, we established a method to quantitatively evaluate the hyphal fusion ability of A. oryzae with mixed culture of two different auxotrophic strains, where the ratio of heterokaryotic conidia growing without the auxotrophic requirements reflects the hyphal fusion efficiency. By employing this method, it was demonstrated that AoSO and AoFus3 are required for hyphal fusion, and that hyphal fusion efficiency of A. oryzae was increased by depleting nitrogen source, including large amounts of carbon source, and adjusting pH to 7.0.

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“…Alternatively, shifts to rich medium might induce the activity of NOX2, thereby bypassing the nox1 deletion. A novel function of NOX1 and NOR1 was recently detected in N. crassa and Botrytis cinerea (Read et al 2012;Roca et al 2012), where a deletion of the corresponding genes abolishes fusion of conidial anastomosis tubes (CATs). S. macrospora does not form any conidia; however, hyphal fusion can be observed within the hyphal network (Rech et al 2007).…”

Section: Discussionmentioning

confidence: 99%

New Insights Into the Roles of NADPH Oxidases in Sexual Development and Ascospore Germination in Sordaria macrospora

et al. 2014

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NADPH oxidase (NOX)-derived reactive oxygen species (ROS) act as signaling determinants that induce different cellular processes. To characterize NOX function during fungal development, we utilized the genetically tractable ascomycete Sordaria macrospora. Genome sequencing of a sterile mutant led us to identify the NADPH oxidase encoding nox1 as a gene required for fruiting body formation, regular hyphal growth, and hyphal fusion. These phenotypes are shared by Δnor1, lacking the NOX regulator NOR1. Further phenotypic analyses revealed a high correlation between increased ROS production and hyphal fusion deficiencies in Δnox1 and other sterile mutants. A genome-wide transcriptional profiling analysis of mycelia and isolated protoperithecia from wild type and Δnox1 revealed that nox1 inactivation affects the expression of genes related to cytoskeleton remodeling, hyphal fusion, metabolism, and mitochondrial respiration. Genetic analysis of Δnox2, lacking the NADPH oxidase 2 gene, Δnor1, and transcription factor deletion mutant Δste12, revealed a strict melanin-dependent ascospore germination defect, indicating a common genetic pathway for these three genes. We report that gsa3, encoding a G-protein a-subunit, and sac1, encoding cAMP-generating adenylate cyclase, act in a separate pathway during the germination process. The finding that cAMP inhibits ascospore germination in a melanin-dependent manner supports a model in which cAMP inhibits NOX2 activity, thus suggesting a link between both pathways. Our results expand the current knowledge on the role of NOX enzymes in fungal development and provide a frame to define upstream and downstream components of the NOX signaling pathways in fungi. D URING sexual reproduction, filamentous fungi generate complex fruiting bodies that contain and protect meiosporangia. We used the ascomycetous model fungus Sordaria macrospora to identify genes directly involved in fruiting body development (Kück et al. 2009;Engh et al. 2010;Kück et al. 2009). Due to its homothallic life style, S. macrospora is able to complete the sexual life cycle without the mating of strains with opposite sex, and therefore, fruiting body-deficient mutants can be recognized directly without the need for crossing experiments. In earlier work, we generated sterile mutants showing a developmental block after formation of young fruiting bodies (protoperithecia), but being unable to generate mature perithecia, and referred to these mutants as pro. Recently, we have applied next-generation genome re-sequencing to identify the genes affected in some of these mutants . Based on this approach, we now have characterized mutant pro32 and show that it carries a mutation in the nox1 gene encoding NAPDH oxidase 1 (NOX1).NADPH oxidase (NOX) enzymes are transmembrane proteins that are highly conserved among eukaryotes and produce reactive oxygen species (ROS) through the oxidation of NADPH (Lambeth 2004;Kawahara and Lambeth 2007). ROS have long been recognized as damaging agents due to uncontrolled oxidizing re...

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Germling fusion via conidial anastomosis tubes in the grey mould Botrytis cinerea requires NADPH oxidase activity

Cited by 77 publications

References 44 publications

Deletion of the Fungal Gene soft Disrupts Mutualistic Symbiosis between the Grass Endophyte Epichloë festucae and the Host Plant

Deletion of the Fungal Gene soft Disrupts Mutualistic Symbiosis between the Grass Endophyte Epichloë festucae and the Host Plant

Establishment of a new method to quantitatively evaluate hyphal fusion ability in Aspergillus oryzae

New Insights Into the Roles of NADPH Oxidases in Sexual Development and Ascospore Germination in Sordaria macrospora

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