Spiral growth of mycelial and reproductive hyphae

Trinci, Anthony P. J.; Saunders, Peter; Gosrani, Rekha; Campbell, Kirstin Anne

doi:10.1016/s0007-1536(79)80113-8

Cited by 24 publications

(8 citation statements)

References 10 publications

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“…Young hyphae of filamentous fungi growing on an agar surface often exhibit spiral growth (29,63). N. crassa hyphae normally spiral in a clockwise direction when viewed from above (Fig.…”

Section: Resultsmentioning

confidence: 99%

Characterization of rco-1 of Neurospora crassa, a Pleiotropic Gene Affecting Growth and Development That Encodes a Homolog of Tup1 of Saccharomyces cerevisiae

Yamashiro

Ebbole

Lee

et al. 1996

Molecular and Cellular Biology

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The filamentous fungus Neurospora crassa undergoes a well-defined developmental program, conidiation, that culminates in the production of numerous asexual spores, conidia. Several cloned genes, including con-10, are expressed during conidiation but not during mycelial growth. Using a previously described selection strategy, we isolated mutants that express con-10 during mycelial growth. Selection was based on expression of an integrated DNA fragment containing the con-10 promoter-regulatory region followed by the initial segment of the con-10 open reading frame fused in frame with the bacterial hygromycin B phosphotransferase structural gene (con10-hph). Resistance to hygromycin results from mutational alterations that allow mycelial expression of the con-10-hph gene fusion. A set of drug-resistant mutants were isolated; several of these had abnormal conidiation phenotypes and were trans-acting, i.e., they allowed mycelial expression of the endogenous con-10 gene. Four of these had alterations at a single locus, designated rco-1 (regulation of conidiation). Strains with the rco-1 mutant alleles were aconidial, female sterile, had reduced growth rates, and formed hyphae that coiled in a counterclockwise direction, opposite that of the wild type. The four rco-1 mutants had distinct conidiation morphologies, suggesting that conidiation was blocked at different stages. Wild-type rco-1 was cloned by a novel procedure employing heterokaryon-assisted transformation and ligation-mediated PCR. The predicted RCO1 polypeptide is a homolog of Tup1 of Saccharomyces cerevisiae, a multidomain protein that mediates transcriptional repression of genes concerned with a variety of processes. Like tup1 mutants, null mutants of rco-1 are viable and pleiotropic. A promoter element was identified that could be responsible for RCO1-mediated vegetative repression of con-10 and other conidiation genes.Neurospora crassa, a filamentous fungus, has three distinct sporulation pathways that lead to the production of either of two types of asexual spores, macroconidia and microconidia, or sexual spores, ascospores. Formation of macroconidia, known as macroconidiation or conidiation (as it will be referred to throughout this paper), has been extensively studied at the morphological level (32,40,53,59,64). Upon receipt of certain environmental cues, e.g., carbon starvation, vegetative tissue, the mycelium, initiates conidiation by producing aerial hyphae that grow away from the nutrient surface. These hyphae undergo apical budding, generating what have been termed minor constriction chains. Subsequent growth by continued apical budding leads to hyphal segments with more pronounced, major constrictions. These proconidial chains continue to differentiate by completing septation at the sites of major constrictions. Just prior to disarticulation of mature conidia, a fragile structure, termed the connective (59), is evident. The connective joins adjacent proconidia and is ultimately cleaved. The entire process of conidiation takes 12 to 24 h. Microc...

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“…Young hyphae of filamentous fungi growing on an agar surface often exhibit spiral growth (29,63). N. crassa hyphae normally spiral in a clockwise direction when viewed from above (Fig.…”

Section: Resultsmentioning

confidence: 99%

Characterization of rco-1 of Neurospora crassa, a Pleiotropic Gene Affecting Growth and Development That Encodes a Homolog of Tup1 of Saccharomyces cerevisiae

Yamashiro

Ebbole

Lee

et al. 1996

Molecular and Cellular Biology

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“…In Pilobolus crystallinus the young sporangiophore tip does not rotate (Ootaki et al, 1993). Others (Madelin et al, 1978;Trinci et al, 1979;Beever, 1980;Sherwood-Higham et al, 1994) have speculated that the spiral growth (coiling) of hyphae of several fungi may be a consequence of axial rotation of the extension zone. Our results with R. solani underscore the need to test these speculations experimentally with surface markers.…”

Section: Lack Of Cell Rotation During Tip Growthmentioning

confidence: 99%

Mapping the Growth of Fungal Hyphae: Orthogonal Cell Wall Expansion during Tip Growth and the Role of Turgor

Bartnicki-García

Bracker

Gierz

et al. 2000

Biophysical Journal

113

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By computer-enhanced videomicroscopy, we mapped the trajectory of external and internal cell surface markers in growing fungal hyphae to determine the pattern of cell wall expansion during apical growth. Carbon particles (India ink) were chosen as external markers for tip expansion of Rhizoctonia solani hyphae. Irregularities in the growing apical walls of R. solani served as internal markers. Marker movement was traced in captured frames from the videotaped sequences. External and internal markers both followed orthogonal trajectories; i.e., they moved perpendicular to the cell surface regardless of their initial position in the hyphal apex. We found no evidence that the tip rotates during elongation. The discovery that the cell wall of a growing hypha expands orthogonally has major repercussions on two fronts: 1) It supports the long-held view that turgor pressure is the main force driving cell wall expansion. 2) It provides crucial information to complete the mathematical derivation of a three-dimensional model of hyphal morphogenesis based on the vesicle supply center concept. In three dimensions, the vesicle gradient generated by the vesicle supply center is insufficient to explain shape; it is also necessary to know the manner in which the existing surface is displaced during wall expansion.

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“…Ritchie also reported a geographic effect on curvature, as colonies of A. ustus exhibited spiral growth in Washington, DC, but not in Morgantown, WV, or New York. Trinci et al (1979) Agar concentration affected both the percentage of hyphae that curved and the degree of curvature. Curvature was less on 0.5% agar than o n 3 -4% agar and was absent in liquid medium.…”

Section: Dried Materialsmentioning

confidence: 99%

Morphology of Sclerotium coffeicola, a tropical foliar pathogen

Hanlin¹,

Tortolero²

1989

Can. J. Bot.

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HANLIN, R. T., and TORTOLERO, 0 . 1989. Morphology of Sclerotium coffeicola, a tropical foliar pathogen. Can. J. Bot. 67: 1852-1860.Sclerotium coffeicola, the cause of target-spot disease of coffee, is reported from Venezuela for the first time. Target spot is a foliar disease characterized by large brown lesions composed of a series of concentric rings. Columnar bundles of hyphae (propagules) form on the undersides of the leaves. Orange sclerotia are produced on infected host tissues and in culture. Hyphal septa are sparse and are of the dolipore type. The sclerotia develop from loose aggregations of interwoven hyphae that become more compact as the sclerotia mature. As the sclerotia develop, most interior hyphae enlarge into inflated, thin-walled cells that are interspersed with scattered, broad, thin-walled hyphae. Circular areas of pseudoparenchymatous cells form in the periphery of the sclerotia where they secrete liquid droplets. The outermost layer or two of cells have slightly thickened walls and are pigmented, but the interior of the sclerotium remains white. The entire sclerotium is covered by two thin layers of an amorphous material.HANLIN, R. T., et TORTOLERO, 0 . 1989. Morphology of Sclerotium coffeicola, a tropical foliar pathogen. Can. J. Bot. 67 : 1852-1860.Les auteurs rapportent pour la premiere fois au VCnCzuCla la presence du Sclerotium coffeicola, l'agent causal de la tache en forme de cible du cafk. La tache en forme de cible est une maladie foliaire caractCrisCe par de grandes lesions brunes montrant une sCrie d'anneaux concentriques. Des faisceaux columnaires d'hyphes (propagules) se foment sous la surface des feuilles. Des sclkrotes oranges se dCveloppent sur les tissus infect& de l'h6te ainsi qu'en culture. Les septations sont peu nombreuses le long des hyphes et montrent des dolipores. Les scltrotes se dCveloppent a partir d'aggregats ldches d'hyphes entrelacCs qui deviennent plus compactes avec la maturation du sclCrote. Avec la maturation du sclkrote, la plupart des hyphes internes s'accroissent en largeur pour former des hyphes gonflks a paroi mince qui sont dispersks parmi des hyphes trapus paroi mince. I1 se forme des rkgions circulaires de cellules pseudoparenchymatiques a la peripherie des sclCrotes, ou elles secrktent des gouttelettes de liquide. La premiere couche, ou les deux couches les plus externes de cellule ont des parois cellulaires 1Cgkrement kpaissies et sont pigmentkes, mais llintCrieur du sclkrote demeure blanc. L'ensemble du sclCrote est recouvert de deux minces couches de matkriel amorphe.[Traduit par la revue] Introduction While collecting plant disease fungi in the Tenitorio Federal Amazonas of southern Venezuela, leaves of Vismia sp. were encountered that had large, zonate, necrotic lesions. These leaves were taken into the laboratory where isolations yielded cultures of a rapidly growing fungus that formed large orange sclerotia. The same fungus was later found on leaves of Coffea canephora var. robusta (Lind.) Chev. (= C. robusta L. Linden) in the Temtorio Fede...

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Spiral growth of mycelial and reproductive hyphae

Cited by 24 publications

References 10 publications

Characterization of rco-1 of Neurospora crassa, a Pleiotropic Gene Affecting Growth and Development That Encodes a Homolog of Tup1 of Saccharomyces cerevisiae

Characterization of rco-1 of Neurospora crassa, a Pleiotropic Gene Affecting Growth and Development That Encodes a Homolog of Tup1 of Saccharomyces cerevisiae

Mapping the Growth of Fungal Hyphae: Orthogonal Cell Wall Expansion during Tip Growth and the Role of Turgor

Morphology of Sclerotium coffeicola, a tropical foliar pathogen

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