scholarly journals Chlamydospore formation in hyphae of Fusarium oxysporum f. sp. raphani.

1983 ◽  
Vol 29 (3) ◽  
pp. 187-193
Author(s):  
HIDEYUKI NAGAO ◽  
TSUTOMU HATTORI
Keyword(s):  
Fusarium Oxysporum ◽  
Chlamydospore Formation

scholarly journals FoSTUA, Encoding a Basic Helix-Loop-Helix Protein, Differentially Regulates Development of Three Kinds of Asexual Spores, Macroconidia, Microconidia, and Chlamydospores, in the Fungal Plant Pathogen Fusarium oxysporum

2004 ◽  
Vol 3 (6) ◽  
pp. 1412-1422 ◽  
Author(s):  
Toshiaki Ohara ◽  
Takashi Tsuge
Keyword(s):  
Fusarium Oxysporum ◽  
Fluorescent Protein ◽  
Negative Regulator ◽  
Vascular Wilt ◽  
Wild Type ◽  
Low Frequencies ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Chlamydospore Formation ◽  
Green Fluorescent

ABSTRACT The soil-borne fungus Fusarium oxysporum causes vascular wilt of a wide variety of plant species. F. oxysporum produces three kinds of asexual spores, macroconidia, microconidia, and chlamydospores. Falcate macroconidia are formed generally from terminal phialides on conidiophores and rarely from intercalary phialides on hyphae. Ellipsoidal microconidia are formed from intercalary phialides on hyphae. Globose chlamydospores with thick walls are developed by the modification of hyphal and conidial cells. Here we describe FoSTUA of F. oxysporum, which differentially regulates the development of macroconidia, microconidia, and chlamydospores. FoSTUA encodes a basic helix-loop-helix protein with similarity to Aspergillus nidulans StuA, which has been identified as a transcriptional regulator controlling conidiation. Nuclear localization of FoStuA was verified by using strains expressing FoStuA-green fluorescent protein fusions. The FoSTUA-targeted mutants exhibited normal microconidium formation in cultures. However, the mutants lacked conidiophores and produced macroconidia at low frequencies only from intercalary phialides. Thus, FoSTUA appears to be necessary to induce conidiophore differentiation. In contrast, chlamydospore formation was dramatically promoted in the mutants. These data demonstrate that FoStuA is a positive regulator and a negative regulator for the development of macroconidia and chlamydospores, respectively, and is dispensable for microconidium formation in cultures. The disease-causing ability of F. oxysporum was not affected by mutations in FoSTUA. However, the mutants produced markedly fewer macroconidia and microconidia in infected plants than the wild type. These results suggest that FoSTUA also has an important role for microconidium formation specifically in infected plants.

Observations on chlamydospore production by Fusarium in a two-salt solution

1970 ◽  
Vol 16 (1) ◽  
pp. 29-32 ◽  
Author(s):  
A. A. Qureshi ◽  
O. T. Page
Keyword(s):  
Magnesium Sulfate ◽  
Fusarium Oxysporum ◽  
Salt Solution ◽  
Potassium Phosphate ◽  
Magnesium Carbonate ◽  
Monobasic Potassium Phosphate ◽  
Chlamydospore Formation

An isolate of Fusarium oxysporum grown in a solution of monobasic potassium phosphate and magnesium sulfate rarely produced chlamydospores. However, when the salt solution was amended with 0.125 mg to 2.0 mg per liter of either glucose or magnesium carbonate, there was an abundant production of chlamydospores within 3 to 4 days after inoculation. While an organic or inorganic source of carbon stimulated chlamydospore formation, repression of chlamydospore production occurred with glucose and magnesium carbonate levels above 2.0 mg per liter. The addition of either an ammonium or nitrate source of nitrogen to the salt solution did not produce additional chlamydospores.

INFLUENCE OF AMINO ACIDS AND SUBSTANCES FROM FLAX ROOTS ON THE SOIL-BORNE PLANT PATHOGEN FUSARIUM OXYSPORUM F. LINI

1977 ◽  
Vol 57 (2) ◽  
pp. 407-411 ◽  
Author(s):  
E. A. PETERSON ◽  
M. I. TIMONIN
Keyword(s):  
Amino Acids ◽  
Fusarium Oxysporum ◽  
Plant Pathogen ◽  
Chlamydospore Formation ◽  
Soil Fungistasis ◽  
Flax Cultivar

Repeated subculturing of different isolates of Fusarium oxysporum f. lini on Czapek’s agar supplemented with specific amino acids caused extensive distortion of hyphal cells and conidia as well as a notable inhibition of chlamydospore formation. Certain amino acids also decreased the virulence of most of the isolates to a wilt-susceptible flax cultivar (Novelty) and affected the extent of counteraction of soil fungistasis brought about by substances from flax roots.

Hyphal parasitism and chlamydospore formation by Fusarium oxysporum on Rhizoctonia solani

1979 ◽  
Vol 67 (3) ◽  
pp. 147-151 ◽  
Author(s):  
R. C. Gupta ◽  
R. S. Upadhyay ◽  
Bharat Rai
Keyword(s):  
Rhizoctonia Solani ◽  
Fusarium Oxysporum ◽  
Chlamydospore Formation

scholarly journals Calcineurin Regulates Conidiation, Chlamydospore Formation and Virulence in Fusarium oxysporum f. sp. lycopersici

2020 ◽  
Vol 11 ◽  
Author(s):  
Yi-Hsuan Hou ◽  
Li-Hang Hsu ◽  
Hsuan-Fu Wang ◽  
Yu-Hsin Lai ◽  
Ying-Lien Chen
Keyword(s):  
Fusarium Oxysporum ◽  
Chlamydospore Formation

scholarly journals Degenerated Virulence and Irregular Development of Fusarium oxysporum f. sp. niveum Induced by Successive Subculture

2020 ◽  
Vol 6 (4) ◽  
pp. 382
Author(s):  
Tao-Ho Chang ◽  
Ying-Hong Lin ◽  
Yu-Ling Wan ◽  
Kan-Shu Chen ◽  
Jenn-Wen Huang ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Early Stage ◽  
Infection Process ◽  
Infested Soil ◽  
Cell Wall Degrading Enzymes ◽  
Related Factors ◽  
Pathogen Virulence ◽  
Chlamydospore Formation ◽  
Gene Transcripts ◽  
Successive Subculture

Successive cultivation of fungi on artificial media has been reported to cause the sectorization, which leads to degeneration of developmental phenotype, and virulence. Fusarium oxysporum f. sp. niveum (Fon), the causal agent of watermelon Fusarium wilt, forms degenerated sectors after successive cultivation. In the present research, we demonstrated that subculture with aged mycelia increased the incidence of degenerations. To further investigate the differences between the Fon wild type (sporodochial type, ST) and variants (MT: mycelial type and PT: pionnotal type), developmental phenotypes and pathogenicity to watermelon were examined. Results in variants (PT2, PT3, PT11, and MT6) were different from ST with mycelia growth, conidia production and chlamydospore formation. Virulence of degenerated variants on susceptible watermelon Grand Baby (GB) cultivar was determined after inoculation with Fon variants and Fon ST. In root dipping methods, Fon variants showed no significant differences in disease progress compared with ST. Fon variants showed a significant decrease in disease progression compared with ST through infested soil inoculation. The contrasting results of two inoculation methods suggest that the degenerative changes due to repeated successive cultivation may lead to the loss of pathogen virulence-related factors of the early stage of Fon infection process. Therefore, cell wall-degrading enzymes (CWDEs; cellulase, pectinase, and xylanase) activities of different variants were analyzed. All Fon degenerated variants demonstrated significant decreases of CWDEs activities compared with ST. Additionally, transcript levels of 9 virulence-related genes (fmk1, fgb1, pacC, xlnR, pl1, rho1, gas1, wc1, and fow1) were assessed in normal state. The degenerated variants demonstrated a significantly low level of tested virulence-related gene transcripts except for fmk1, xlnR, and fow1. In summary, the degeneration of Fon is triggered with successive subculture through aged mycelia. The degeneration showed significant impacts on virulence to watermelon, which was correlated with the reduction of CWDEs activities and declining expression of a set of virulence-related genes.

scholarly journals Degenerated virulence and irregular development of Fusarium oxysporum f. sp. niveum induced by successive subculture

2020 ◽  
Author(s):  
Tao-Ho Chang ◽  
Ying-Hong Lin ◽  
Yu-Ling Wan ◽  
Kan-Shu Chen ◽  
Jenn-Wen Huang ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Early Stage ◽  
Infection Process ◽  
Infested Soil ◽  
Cell Wall Degrading Enzymes ◽  
Related Factors ◽  
Mycelium Growth ◽  
Pathogen Virulence ◽  
Chlamydospore Formation ◽  
Successive Subculture

AbstractSuccessive cultivation of fungus has been reported to cause the sectorization, which leads to degeneration of developmental phenotype, and virulence. Fusarium oxysporum f. sp. niveum (Fon), the causal agent of watermelon Fusarium wilt, demonstrated that successive cultivation formed the degenerated sectors. In the present research, we demonstrated that subculture with aged mycelium increased the incidence of degenerations. To further investigate the differences between the Fon wild type (sporodochial type, ST) and variants (MT: mycelium type and PT: pionnotal type), developmental phenotypes and pathogenicity to watermelon were examined. Results have shown that degeneration variants (PT2, PT3, PT11 and MT6) were different from ST with mycelium growth, conidia production and chlamydospore formation. Virulence of degenerated variants on susceptible watermelon Grand Baby (GB) cultivar was determined after inoculated with Fon variants and Fon ST. In root dipping methods, all Fon variants showed slightly increased disease severity than ST. Conversely, all Fon variants showed a significant decrease in disease progression compared with ST through infested soil inoculation. The contrary results of two inoculation methods suggest that the changes of successive cultural degeneration may lead to the loss of pathogen virulence-related factors of the early stage of Fon infection process. Therefore, Cell wall-degrading enzymes (CWDEs; cellulase, pectinase, and xylanase) activities of different variants were analysed. All Fon degenerated variants demonstrated significantly decreased of CWDEs activities compared with ST. Additionally, transcripts level of 9 virulence-related genes (fmk1, fgb1, pacC, xlnR, pl1, rho1, gas1, wc1 and fow1) were assessed in normal state. The degenerated variants demonstrated a significantly low level of tested virulence-related genes transcripts except for fmk1, xlnR and fow1. In summary, the degeneration of Fon is triggered with successive subculture through aged mycelium. The degeneration showed significant impacts on virulence to watermelon, which caused by the reduction of CWDEs activities and declining expression of a set of virulence-related genes.

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