Altering the expression of two chitin synthase genes differentially affects the growth and morphology of Aspergillus oryzae The GenBank accession numbers for the chsB, chsC and chsA gene sequences reported in this paper are AY029261, AF410464 and AF429307, respectively.

Müller, Christian; Hjort, Carsten; Hansen, Kim Toft; Nielsen, Jens

doi:10.1099/00221287-148-12-4025

Cited by 36 publications

(25 citation statements)

References 30 publications

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“…Elimination or reduction of the expression of chsB or csmA caused obvious defects in hyphal growth and asexual development (3,18,21,43,58). Analogous observations have also been reported in other filamentous fungi (2,23,25,31,59). Deletion mutants of chsA, chsC, or chsD exhibited no clear morphological differences from the wild-type strain (29,30,58).…”

supporting

confidence: 55%

Class I and Class II Chitin Synthases Are Involved in Septum Formation in the Filamentous Fungus Aspergillus nidulans

Ichinomiya¹,

Yamada²,

Yamashita

et al. 2005

Eukaryot Cell

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The class II and class I chitin synthases of the filamentous fungus Aspergillus nidulans are encoded by chsA and chsC, respectively. Previously, we presented several lines of evidence suggesting that ChsA and ChsC have overlapping functions in maintaining cell wall integrity. In order to determine the functions of these chitin synthases, we employed electron and fluorescence microscopy and investigated in detail the cell wall of a ⌬chsA ⌬chsC double mutant (⌬AC mutant) along with the localization of ChsA and ChsC. In the lateral cell wall of the ⌬AC mutant, electron-transparent regions were thickened. Septa of the ⌬AC mutant were aberrantly thick and had a large pore. Some septa were located abnormally close to adjacent septa. A functional hemagglutinin (HA)-tagged ChsA (HA-ChsA) and a functional FLAG-tagged ChsC (FLAG-ChsC) were each localized to a subset of septation sites. Comparison with the localization pattern of actin, which is known to localize at forming septa, suggested that ChsA and ChsC transiently exist at the septation sites during and shortly after septum formation. Double staining of HA-ChsA and FLAG-ChsC indicated that their localizations were not identical but partly overlapped at the septation sites. Fluorescence of FLAG-ChsC, but not of HA-ChsA, was also observed at hyphal tips. These data indicate that ChsA and ChsC share overlapping roles in septum formation.

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supporting

confidence: 55%

Class I and Class II Chitin Synthases Are Involved in Septum Formation in the Filamentous Fungus Aspergillus nidulans

Ichinomiya¹,

Yamada²,

Yamashita

et al. 2005

Eukaryot Cell

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“…Chitin confers stability to the cell wall; therefore, it is not surprising that CHS mutants are often defective in cell morphology (Shaw et al, 1991;Borgia et al, 1996;Muller et al, 2002). We describe here that Chs5 and Chs7 are most important for the morphology of yeast-like cells, conjugation hyphae, and dikaryotic hyphae of U. maydis (Figure 10).…”

Section: U Maydis Contains Eight Chssmentioning

confidence: 82%

“…This raises doubts about specific cellular functions of individual classes of CHS. Indeed, it was reported that class III CHSs are not important in U. maydis (Gold and Kronstad, 1994) and apparently do not even exist in Phycomyces blakesleeanus (Miyazaki and Ootaki, 1997), whereas this class has crucial functions in morphogenesis in Aspergillus oryzae (Muller et al, 2002) and Aspergillus nidulans . The situation is even more complicated by the fact that CHSs of different classes cooperate to mediate conidiation and hyphal growth (Motoyama et al, 1996;Fujiwara et al, 2000) or fungal virulence (Wang et al, 2001).…”

Section: U Maydis Contains Eight Chssmentioning

confidence: 99%

Polar Localizing Class V Myosin Chitin Synthases Are Essential during Early Plant Infection in the Plant Pathogenic FungusUstilago maydis

Weber¹,

Daniela²,

Thines³

et al. 2005

The Plant Cell

131

154

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Fungal chitin synthases (CHSs) form fibers of the cell wall and are crucial for substrate invasion and pathogenicity. Filamentous fungi contain up to 10 CHSs, which might reflect redundant functions or the complex biology of these fungi. Here, we investigate the complete repertoire of eight CHSs in the dimorphic plant pathogen Ustilago maydis. We demonstrate that all CHSs are expressed in yeast cells and hyphae. Green fluorescent protein (GFP) fusions to all CHSs localize to septa, whereas Chs5-GFP, Chs6-GFP, Chs7-yellow fluorescent protein (YFP), and Myosin chitin synthase1 (Mcs1)-YFP were found at growth regions of yeast-like cells and hyphae, indicating that they participate in tip growth. However, only the class IV CHS genes chs7 and chs5 are crucial for shaping yeast cells and hyphae ex planta. Although most CHS mutants were attenuated in plant pathogenicity, Dchs6, Dchs7, and Dmcs1 mutants were drastically reduced in virulence. Dmcs1 showed no morphological defects in hyphae, but Mcs1 became essential during invasion of the plant epidermis. Dmcs1 hyphae entered the plant but immediately lost growth polarity and formed large aggregates of spherical cells. Our data show that the polar class IV CHSs are essential for morphogenesis ex planta, whereas the class V myosin-CHS is essential during plant infection.

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“…1 and 2). Formations of intrahyphal hyphae or double-layered cell walls were observed in some deletion mutants of the class V or VI chitin synthase-encoding genes and the genes involved in the biosynthesis of the glycosylphosphatidylinositol anchor that connects proteins working for cell wall structure maintenance (4,14,25,26,32,44). In N. crassa and Aspergillus oryzae, it has been reported that new hyphae are generated from septa when Woronin body plugged a septal pore (19,27,45).…”

Section: Discussionmentioning

confidence: 99%

Class III Chitin Synthase ChsB of Aspergillus nidulans Localizes at the Sites of Polarized Cell Wall Synthesis and Is Required for Conidial Development

Fukuda¹,

Yamada²,

Deoka³

et al. 2009

Eukaryot Cell

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Class III chitin synthases play important roles in tip growth and conidiation in many filamentous fungi. However, little is known about their functions in those processes. To address these issues, we characterized the deletion mutant of a class III chitin synthase-encoding gene of Aspergillus nidulans, chsB, and investigated ChsB localization in the hyphae and conidiophores. Multilayered cell walls and intrahyphal hyphae were observed in the hyphae of the chsB deletion mutant, and wavy septa were also occasionally observed. ChsB tagged with FLAG or enhanced green fluorescent protein (EGFP) localized mainly at the tips of germ tubes, hyphal tips, and forming septa during hyphal growth. EGFP-ChsB predominantly localized at polarized growth sites and between vesicles and metulae, between metulae and phialides, and between phalides and conidia in asexual development. These results strongly suggest that ChsB functions in the formation of normal cell walls of hyphae, as well as in conidiophore and conidia development in A. nidulans.Chitin, a polymer of ␤-1,4-linked N-acetylglucosmine, is one of the major structural components of the fungal cell wall. Its metabolism, including synthesis, degradation, assembly, and cross-linking to other cell wall components, is thought to be very important for many fungi (5,22,24,36,45). Fungal chitin synthases have been classified into seven groups, classes I to VII, depending on the structures of their conserved regions (6). The genes encoding the synthases belonging to classes III, V, VI, and VII are only found in fungi with high chitin contents in their cell walls. We have identified six chitin synthase genes from Aspergillus nidulans and designated them chsA, chsB, chsC, chsD, csmA, and csmB; these gene products belong to classes II, III, I, IV, V, and VI, respectively (9,13,30,31,44,52). The chsB deletion mutant grew very slowly and formed small colonies with highly branched hyphae, suggesting its important role in hyphal tip growth (3, 52). Repression of chsB expression in the deletion mutant of chsA, chsC, or chsD exaggerated the defects in the formation of aerial hyphae, the production of cell mass, or the growth under high-osmolarity conditions, respectively, compared to each single mutant. These results indicate that chsB functions at various stages of development (15, 16).The deletion of class III chitin synthase-encoding genes leads to severe defects in most of the filamentous fungi thus far investigated. However, their detailed functions are currently unknown. In Neurospora crassa, inactivation of the gene encoding Chs-1, a class III chitin synthase with 63% identity to A. nidulans ChsB, leads to slow growth, aberrant hyphal morphology, and a decrease in chitin synthase activity. The mutant of chs-1 became sensitive to Nikkomycin Z, a chitin synthase inhibitor (53). In Aspergillus fumigatus, two genes encoding class III chitin synthases, chsC and chsG, have been identified. Their gene products showed 66 and 89% identity, respectively, to A. nidulans ChsB. The chsG deletio...

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Altering the expression of two chitin synthase genes differentially affects the growth and morphology of Aspergillus oryzae The GenBank accession numbers for the chsB, chsC and chsA gene sequences reported in this paper are AY029261, AF410464 and AF429307, respectively.

Cited by 36 publications

References 30 publications

Class I and Class II Chitin Synthases Are Involved in Septum Formation in the Filamentous Fungus Aspergillus nidulans

Class I and Class II Chitin Synthases Are Involved in Septum Formation in the Filamentous Fungus Aspergillus nidulans

Polar Localizing Class V Myosin Chitin Synthases Are Essential during Early Plant Infection in the Plant Pathogenic FungusUstilago maydis

Class III Chitin Synthase ChsB of Aspergillus nidulans Localizes at the Sites of Polarized Cell Wall Synthesis and Is Required for Conidial Development

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