F-actin localization dynamics during appressorium formation in Colletotrichum graminicola

Mycologia ◽  
2016 ◽  
Vol 108 (3) ◽  
pp. 506-514 ◽  
Author(s):  
Chih-Li Wang ◽  
Brian D. Shaw
Keyword(s):  
Colletotrichum Graminicola ◽  
Appressorium Formation ◽  
Actin Localization

Early interactions, adhesion, and establishment of the infection court by Erysiphe graminis

1995 ◽  
Vol 73 (S1) ◽  
pp. 609-615 ◽  
Author(s):  
Ralph L. Nicholson ◽  
Hitoshi Kunoh
Keyword(s):  
Hydrophobic Surface ◽  
Surface Hydrophobicity ◽  
Infection Process ◽  
Erysiphe Graminis ◽  
Hydrophilic Surface ◽  
Colletotrichum Graminicola ◽  
Appressorium Formation ◽  
Barley Leaf ◽  
Powdery Mildew Pathogen ◽  
Suitable Substratum

The establishment of a fungal pathogen on the surface of its host is essential to the success of the infection process. For many fungi, establishment on the host is an active process that may depend on recognition of the host surface through chemical or topographic signals. Events that allow for establishment may be considered to represent the "preparation of the infection court" by the pathogen. This sometimes involves the adhesion of the pathogen to the host and possibly the alteration of the host's surface topography or chemistry. Adhesion is often presumed to be a single, chemically mediated event associated with germ tube or appressorium formation. However, adhesion of ungerminated propagules may also occur, and evidence suggests that it is mediated by the release of adhesive materials directly from the propagule upon contact with a suitable substratum. Fungi may require either a hydrophobic or a hydrophilic surface to initiate the infection process. The barley powdery mildew pathogen, Erysiphe graminis, requires a hydrophilic surface for appressorium formation, yet the barley leaf is extremely hydrophobic. The problem is resolved by the release of an exudate from conidia that makes the hydrophobic leaf surface hydrophilic. In contrast, Colletotrichum graminicola requires a hydrophobic surface for the initiation of its infection process. Ungerminated conidia of this fungus release materials that allow for the rapid adhesion of conidia, which ensures that germination and appressorium formation occur, initiating the infection process. For both fungi, these events happen well in advance of germination and establish the pathogen at the site of the infection court. Key words: adhesion, cuticle, cutinase, surface hydrophobicity, infection process.

scholarly journals Bypassing Both Surface Attachment and Surface Recognition Requirements for Appressorium Formation by Overactive Ras Signaling in Magnaporthe oryzae

2014 ◽  
Vol 27 (9) ◽  
pp. 996-1004 ◽  
Author(s):  
Xiaoying Zhou ◽  
Xinhua Zhao ◽  
Chaoyang Xue ◽  
Yafeng Dai ◽  
Jin-Rong Xu
Keyword(s):  
Magnaporthe Oryzae ◽  
Pathogenic Fungi ◽  
Mitogen Activated Protein Kinase ◽  
Ras Signaling ◽  
Colletotrichum Graminicola ◽  
Appressorium Formation ◽  
Surface Attachment ◽  
Surface Recognition ◽  
Aerial Hyphae ◽  
Liquid Suspensions

Magnaporthe oryzae forms a highly specialized infection structure called an appressorium for plant penetration. In M. oryzae and many other plant-pathogenic fungi, surface attachment and surface recognition are two essential requirements for appressorium formation. Development of appressoria in the air has not been reported. In this study, we found that expression of a dominant active MoRAS2G18V allele in M. oryzae resulted in the formation of morphologically abnormal appressoria on nonconducive surfaces, in liquid suspensions, and on aerial hyphae without attachment to hard surfaces. Both the Pmk1 mitogen-activated protein kinase cascade and cAMP signaling pathways that regulate surface recognition and appressorium morphogenesis in M. oryzae were overactivated in the MoRAS2G18V transformant. In mutants deleted of PMK1 or CPKA, expression of MoRAS2G18V had no significant effects on appressorium morphogenesis. Furthermore, expression of dominant MoRAS2 in Colletotrichum graminicola and C. gloeosporioides also caused the formation of appressorium-like structures in aerial hyphae. Overall, our data indicate that MoRas2 functions upstream from both the cAMP-PKA and Pmk1 pathways and overactive Ras signaling leads to improper activation of these two pathways and appressorium formation without surface attachment in appressorium-forming pathogens.

Studies on hyphal development and appressorium formation of Colletotrichum graminicola

1978 ◽  
Vol 56 (18) ◽  
pp. 2234-2242 ◽  
Author(s):  
F. Kozar ◽  
Hans J. Netolitzky
Keyword(s):  
Germ Tube ◽  
Thick Wall ◽  
Colletotrichum Graminicola ◽  
Appressorium Formation ◽  
Reserve Material ◽  
Lipid Reserve ◽  
Mucilaginous Sheath ◽  
Stage Of Development ◽  
Definition Of ◽  
Cellular Organelles

The fine structure of actively growing hyphae of Colletotrichum graminicola was investigated. The hyphae were found to secrete a mucilaginous sheath into which melanizing particles and fibrils were deposited. Classical ubiquitous mitochondria, multipored doublewalled nuclei, ribosomes, mesosome-like structures, lomosomes, vacuoles, and inclusions such as lipids, closely associated with vacuoles, especially noticeable during germination, as well as glycogen were present. During maturation, vacuoles appeared and enlarged. In addition, a few endoplasmic reticulum profiles were observed in actively growing hyphae. Mitochondrial profiles changed from spherical to elongate. A plasmalemma, perhaps double in nature, was present. Penetration of one hypha by another was also observed.The mature appressorium exhibited a thick three-layered cell wall. This thick wall appeared to play a part in poor fixation and embedding, resulting in a poor definition of such cellular organelles as ribosomes, nuclei, etc. Internally, appressoria, depending on the stage of development, exhibited many vacuoles and osmiophilic deposits indicative of lipid reserve material. A germ pore through which a germ tube and migrating organelles and cytoplasm emerged was also observed.

EFFECT OF SULFUR COMPOUNDS ON APPRESSORIUM FORMATION BY COLLETOTRICHUM GRAMINICOLA

1971 ◽  
Vol 51 (1) ◽  
pp. 49-51 ◽  
Author(s):  
H. J. NETOLITZKY ◽  
W. P. SKOROPAD
Keyword(s):  
Reduced Glutathione ◽  
Methionine Sulfoxide ◽  
Sulfhydryl Groups ◽  
Cysteic Acid ◽  
Colletotrichum Graminicola ◽  
Appressorium Formation ◽  
Cysteine Sulfinic Acid ◽  
Homocysteic Acid ◽  
Methionine Sulfone

Compounds containing sulfhydryl groups inhibited appressorium formation by Colletotrichum graminicola (Ces.) Wils. Appressoria were not formed in 0.03 and 0.06 M solutions of cysteine, homocysteine, thiohistidine and reduced glutathione. They were formed abundantly within 24 hr in 0.006, 0.03 and 0.06 M solutions of cysteine sulfinic acid, cysteic acid, homocysteic acid, S-methyl cysteine, methionine, methionine sulfone, methionine sulfoxide, and oxidized glutathione. The role of sulfhydryl groups in the inhibition of appressorium formation is discussed.

The Identity and Perfect State of Colletotrichum graminicola

Mycologia ◽  
1975 ◽  
Vol 67 (1) ◽  
pp. 56 ◽  
Author(s):  
Demetrios J. Politis
Keyword(s):  
Perfect State ◽  
Colletotrichum Graminicola

scholarly journals Transcriptomics differentiate two novel bioactive strains of Paenibacillus sp. isolated from the perennial ryegrass seed microbiome

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tongda Li ◽  
Ross Mann ◽  
Jatinder Kaur ◽  
German Spangenberg ◽  
Timothy Sawbridge
Keyword(s):  
Nitrogen Fixation ◽  
Secondary Metabolite ◽  
Perennial Ryegrass ◽  
Fusarium Verticillioides ◽  
In Vitro Assays ◽  
Colletotrichum Graminicola ◽  
Nitrogen Fixation Activity ◽  
Auxin Production ◽  
Paenibacillus Sp

AbstractPaenibacillus species are Gram-positive bacteria that have been isolated from a diverse array of plant species and soils, with some species exhibiting plant growth-promoting (PGP) activities. Here we report two strains (S02 and S25) of a novel Paenibacillus sp. that were isolated from perennial ryegrass (Lolium perenne) seeds. Comparative genomics analyses showed this novel species was closely related to P. polymyxa. Genomic analyses revealed that strains S02 and S25 possess PGP genes associated with biological nitrogen fixation, phosphate solubilisation and assimilation, as well as auxin production and transportation. Moreover, secondary metabolite gene cluster analyses identified 13 clusters that are shared by both strains and three clusters unique to S25. In vitro assays demonstrated strong bioprotection activity against phytopathogens (Colletotrichum graminicola and Fusarium verticillioides), particularly for strain S02. A transcriptomics analysis evaluating nitrogen fixation activity showed both strains carry an expressed nif operon, but strain S02 was more active than strain S25 in nitrogen-free media. Another transcriptomics analysis evaluating the interaction of strains with F. verticillioides showed strain S02 had increased expression of core genes of secondary metabolite clusters (fusaricidin, paenilan, tridecaptin and polymyxin) when F. verticillioides was present and absent, compared to S25. Such bioactivities make strain S02 a promising candidate to be developed as a combined biofertiliser/bioprotectant.

scholarly journals Protein phosphatase inhibitors okadaic acid and calyculin A alter cell shape and F-actin distribution and inhibit stimulus-dependent increases in cytoskeletal actin of human neutrophils

Blood ◽  
1992 ◽  
Vol 80 (11) ◽  
pp. 2911-2919 ◽  
Author(s):  
P Kreienbuhl ◽  
H Keller ◽  
V Niggli
Keyword(s):  
Okadaic Acid ◽  
Human Neutrophils ◽  
Resting Cells ◽  
Calyculin A ◽  
Chemotactic Peptide ◽  
Phosphatase Inhibitors ◽  
Protein Phosphatase Inhibitors ◽  
Actin Localization ◽  
Shape Changes

Abstract The phosphatase inhibitors okadaic acid and calyculin A were found to elicit or to modify several neutrophil responses, suggesting that dephosphorylation plays a regulatory role. The concentrations of okadaic acid (> or = 1 mumol/L) that were effective on neutrophil functions (shape changes and marginal stimulation of pinocytosis) were shown to stimulate the incorporation of 32PO4 into many neutrophil proteins several-fold. Calyculin A was effective at 50-fold lower concentrations. In the presence of the inhibitors, the cells exhibited a nonpolar shape and the polarization response induced by chemotactic peptide was inhibited. Both phosphatase inhibitors also induced the association of F-actin with the cell membrane. A steady-state phosphatase activity is thus involved in maintaining shape and F-actin localization of resting cells. Inhibitors alone had no significant effect on the amount of cytoskeleton-associated actin. The increase in cytoskeletal actin observed at 30 minutes of stimulation with phorbol ester or 5 to 30 minutes of stimulation with chemotactic peptide, however, was abolished by okadaic acid or calyculin A, suggesting an important role of a phosphatase. In contrast, the early increase in cytoskeleton-associated actin observed at 1 minute of stimulation with peptide was not affected. This finding indicates that the increased association of actin with the cytoskeleton in the early and the later stages of neutrophil activation may be mediated by different signalling pathways.

Quantification of substratum contact required for initiation of Colletotrichum graminicola appressoria

2004 ◽  
Vol 41 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Dace Apoga ◽  
John Barnard ◽  
Harold G. Craighead ◽  
Harvey C. Hoch
Keyword(s):  
Colletotrichum Graminicola
Sign in / Sign up

Export Citation Format

Share Document