Hydrophobicity of contact surface induces appressorium formation in Magnaporthe grisea

1994 ◽  
Vol 115 (1) ◽  
pp. 71-75 ◽  
Author(s):  
R Yong-Hwan Lee
Keyword(s):  
Contact Surface ◽  
Magnaporthe Grisea ◽  
Appressorium Formation

scholarly journals Inhibition of Fungal Appressorium Formation by Pepper (Capsicum annuum) Esterase

2001 ◽  
Vol 14 (1) ◽  
pp. 80-85 ◽  
Author(s):  
Young Soon Kim ◽  
Hyun Hwa Lee ◽  
Moon Kyung Ko ◽  
Chae Eun Song ◽  
Cheol-Yong Bae ◽  
...  
Keyword(s):  
Recombinant Protein ◽  
Capsicum Annuum ◽  
Magnaporthe Grisea ◽  
Dependent Manner ◽  
Appressorium Formation ◽  
Glutathione S Transferase ◽  
Porcine Liver ◽  
Esterase Gene ◽  
Dose Dependent ◽  
Dependent Signaling Pathway

A pepper esterase gene (PepEST) that is highly expressed during an incompatible interaction between pepper (Capsicum annuum) and the anthracnose fungus Colletotrichum gloeosporioides has been previously cloned. Glutathione-S-transferase-tagged recombinant PepEST protein expressed in Escherichia coli showed substrate specificity for p-nitrophenyl esters. Inoculation of compatible unripe pepper fruits with C. gloeosporioides spores amended with the recombinant protein did not cause anthracnose symptoms on the fruit. The recombinant protein has no fungicidal activity, but it significantly inhibits appressorium formation of the anthracnose fungus in a dose-dependent manner. An esterase from porcine liver also inhibited appressorium formation, and the recombinant protein inhibited appressorium formation in the rice blast fungus, Magnaporthe grisea. Inhibition of appressorium formation in M. grisea by the recombinant protein was reversible by treatment with cyclic AMP (cAMP) or 1,16-hexadecanediol. The results suggest that the recombinant protein regulates appressorium formation by modulating the cAMP-dependent signaling pathway in this fungus. Taken together, the PepEST esterase activity can inhibit appressorium formation of C. gloeosporioides, which may result in protection of the unripe fruit against the fungus.

Proteome analysis of rice blast fungus (Magnaporthe grisea) proteome during appressorium formation

PROTEOMICS ◽  
2004 ◽  
Vol 4 (11) ◽  
pp. 3579-3587 ◽  
Author(s):  
Sun Tae Kim ◽  
Seok Yu ◽  
Sang Gon Kim ◽  
Han Ju Kim ◽  
Sun Young Kang ◽  
...  
Keyword(s):  
Rice Blast ◽  
Magnaporthe Grisea ◽  
Proteome Analysis ◽  
Rice Blast Fungus ◽  
Appressorium Formation ◽  
Blast Fungus

scholarly journals G Protein α Subunit Genes Control Growth, Development, and Pathogenicity of Magnaporthe grisea

1997 ◽  
Vol 10 (9) ◽  
pp. 1075-1086 ◽  
Author(s):  
Shaohua Liu ◽  
Ralph A. Dean
Keyword(s):  
Neurospora Crassa ◽  
G Protein ◽  
Vegetative Growth ◽  
Magnaporthe Grisea ◽  
Cryphonectria Parasitica ◽  
Appressorium Formation ◽  
Α Subunit ◽  
Targeted Deletion ◽  
Control Growth ◽  
G Protein Α Subunit

Three G protein α subunit genes have been cloned and characterized from Magnaporthe grisea: magA is very similar to CPG-2 of Cryphonectria parasitica; magB is virtually identical to CPG-1 of Cryphonectria parasitica, to gna1 of Neurospora crassa, and to fadA of Emericella nidulans; and magC is most similar to gna2 of Neurospora crassa. Homologous recombination resulting in targeted deletion of magA had no effect on vegetative growth, conidiation, or appressorium formation. Deletion of magC reduced conidiation, but did not affect vegetative growth or appressorium formation. However, disruption of magB significantly reduced vegetative growth, conidiation, and appressorium formation. magB¯ transformants, unlike magA¯ and magC¯ transformants, exhibited a reduced ability to infect and colonize susceptible rice leaves. G protein α subunit genes are required for M. grisea mating. magB¯ transformants failed to form perithecia, whereas magA¯ and magC¯ transformants did not produce mature asci. These results suggest that G protein α subunit genes are involved in signal transduction pathways in M. grisea that control vegetative growth, conidiation, conidium attachment, appressorium formation, mating, and pathogenicity.

scholarly journals Cyclic AMP Restores Appressorium Formation Inhibited by Polyamines in Magnaporthe grisea

1998 ◽  
Vol 88 (1) ◽  
pp. 58-62 ◽  
Author(s):  
Woo-Bong Choi ◽  
Shin-Ho Kang ◽  
Yin-Won Lee ◽  
Yong-Hwan Lee
Keyword(s):  
Cyclic Amp ◽  
Magnaporthe Grisea ◽  
Conidial Germination ◽  
Intracellular Camp ◽  
Elevated Concentration ◽  
Appressorium Formation ◽  
Polyamine Biosynthesis ◽  
Wide Range ◽  
Biosynthesis Inhibitors ◽  
Exogenous Addition

Magnaporthe grisea, the causal agent of rice blast, forms a dome-shaped melanized infection structure, an appressorium, to infect its host. Environmental cues that induce appressorium formation in this fungus include the hydrophobicity and hardness of the contact surface and chemicals produced by the host. An elevated concentration of intracellular cyclic AMP (cAMP) has been implicated in appressorium differentiation in M. grisea. Polyamines (putrescine, spermidine, and sper-mine) are involved in cell growth and differentiation in a wide range of organisms. To understand the role of polyamines in appressorium differentiation in M. grisea, intracellular polyamines were quantified, and the effects of polyamines and polyamine biosynthesis inhibitors on conidial germination and appressorium formation were tested. High levels of polyamines were detected in freshly collected spores, but the levels decreased during conidial germination. Spermidine was found to be the major component. Polyamines and polyamine biosynthesis inhibitors did not affect conidial germination, but polyamines specifically impaired appressorium formation. Furthermore, exogenous addition of cAMP restored appressorium formation inhibited by poly-amines. These results suggest that polyamines may reduce intracellular cAMP levels in M. grisea, leading to the inhibition of appressorium formation.

scholarly journals A Target-Site-Specific Screening System for Antifungal Compounds on Appressorium Formation in Magnaporthe grisea

2000 ◽  
Vol 90 (10) ◽  
pp. 1162-1168 ◽  
Author(s):  
Hong-Sik Oh ◽  
Yong-Hwan Lee
Keyword(s):  
Ethyl Acetate ◽  
Rice Blast ◽  
Magnaporthe Grisea ◽  
Pathogenic Fungi ◽  
Antifungal Compounds ◽  
Screening System ◽  
Appressorium Formation ◽  
Culture Filtrates ◽  
Water Fractions ◽  
Chemical Fungicides

Chemical fungicides are a major method of control for plant diseases in spite of potential negative effects on the environment and the appearance of resistant strains. Development of new chemical fungicides has been largely dependent upon in vivo efficacy tests in the greenhouse or in fields, which is in contrast to target-oriented in vitro screening systems widely used in the pharmaceutical field. To establish a target-site—specific screening system for antifungal compounds, specific inhibition on appressorium formation of the rice blast fungus Magnaporthe grisea was employed. For many plant-pathogenic fungi, including M. grisea, appressorium formation is an essential step to infect host plants. Among 1,000 culture filtrates of members of the class Actinomycetes and fungi, five (A5005, A5008, A5314, A5387, and A5397) from the class Actinomycetes showed differential inhibitory effects on appressorium formation of M. grisea in a dosage-dependent manner. Three (A5005, A5314, and A5387) of these were further fractionated into ethyl acetate and water fractions. The ethyl acetate fraction of A5005 and both the ethyl acetate and water fractions from A5314 and A5387 inhibited appressorium formation, while conidial germination remained little affected. Inhibition of appressorium formation by the ethyl acetate or water fraction was reversed by the exogenous addition of cyclic AMP. Significantly reduced numbers of conidia with appressoria were observed on rice leaves in the presence of culture filtrates. Furthermore, these culture filtrates also exhibited significant disease control of rice blast in the greenhouse. This rapid and target-oriented screening system could be adopted to screen candidate compounds for rice blast control and could be applicable for other appressorium-forming, plant-pathogenic fungi.

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