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Botrytis cinerea protein O-mannosyltransferases play critical roles in morphogenesis, growth, and virulence.

González M, Brito N, Frías M, González C - PLoS ONE (2013)

Bottom Line: The most significant case is that of grapevine leaves, whose penetration requires the three functional PMTs.Furthermore, PMT2 also contributes significantly to fungal adherence on grapevine and tobacco leaves.Analysis of extracellular and membrane proteins showed significant changes in the pattern of protein secretion and glycosylation by the pmt mutants, and allowed the identification of new protein substrates putatively glycosylated by specific PMTs.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de La Laguna, La Laguna (Tenerife), Spain.

ABSTRACT
Protein O-glycosylation is crucial in determining the structure and function of numerous secreted and membrane-bound proteins. In fungi, this process begins with the addition of a mannose residue by protein O-mannosyltransferases (PMTs) in the lumen side of the ER membrane. We have generated mutants of the three Botrytis cinerea pmt genes to study their role in the virulence of this wide-range plant pathogen. B. cinerea PMTs, especially PMT2, are critical for the stability of the cell wall and are necessary for sporulation and for the generation of the extracellular matrix. PMTs are also individually required for full virulence in a variety of hosts, with a special role in the penetration of intact plant leaves. The most significant case is that of grapevine leaves, whose penetration requires the three functional PMTs. Furthermore, PMT2 also contributes significantly to fungal adherence on grapevine and tobacco leaves. Analysis of extracellular and membrane proteins showed significant changes in the pattern of protein secretion and glycosylation by the pmt mutants, and allowed the identification of new protein substrates putatively glycosylated by specific PMTs. Since plants do no possess these enzymes, PMTs constitute a promising target in the development of novel control strategies against B. cinerea.

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Related in: MedlinePlus

Hyphal morphology of the Δbcpmt mutant strains.The three mutants and the wild type (B05.10) were grown in MB. 1 M sorbitol was added to the medium where indicated. A) Morphology under the microscope. B) Morphology under the scanning electron microscope.
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pone-0065924-g006: Hyphal morphology of the Δbcpmt mutant strains.The three mutants and the wild type (B05.10) were grown in MB. 1 M sorbitol was added to the medium where indicated. A) Morphology under the microscope. B) Morphology under the scanning electron microscope.

Mentions: Microscopic observation of Δbcpmt mutants, grown in the chemically defined medium MB supplemented, or not, with 1 M Sorbitol, revealed big morphological changes in the hyphae of Δbcpmt2 and Δbcpmt4, especially the former (Figure 6). The most significant of these changes was the increase in the thickness of cells and the presence of balloon-like swollen cells in these two mutants, which partially disappear when 1 M sorbitol was included in the culture (Figure 6A). As discussed before, this can be explained by a softened cell wall not able to withstand the osmotic pressure. Similar morphologies have also been observed in pmt mutants in Asperglillus awamori[16], A. nidulans[33], [40], A. fumigatus[41] or Neurospora crassa[42]. Curiously, Δbcpmt2 also displayed a more frequent appearance of septa separating individual cells (Figure 6A), especially evident when staining with CW (not shown). The branching pattern was also different for Δbcpmt2 and Δbcpmt4, with a higher number of branching points in both of them (Figure 6B). Overall, it seems that Δbcpmt1 is morphologically similar to the wild type, Δbcpmt2 presents swollen, more frequently septated, and hyperbranched hyphae forming compact colonies, and Δbcpmt4 displays morphological characteristics which are intermediate between the wild type and Δbcpmt2. All these changes, with the clear exception of the increase in septum frequency, reverted with the addition of the osmotic stabilizer sorbitol, indicating that they are probably the consequence of the osmotic pressure acting on a weakened cell wall.


Botrytis cinerea protein O-mannosyltransferases play critical roles in morphogenesis, growth, and virulence.

González M, Brito N, Frías M, González C - PLoS ONE (2013)

Hyphal morphology of the Δbcpmt mutant strains.The three mutants and the wild type (B05.10) were grown in MB. 1 M sorbitol was added to the medium where indicated. A) Morphology under the microscope. B) Morphology under the scanning electron microscope.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3675079&req=5

pone-0065924-g006: Hyphal morphology of the Δbcpmt mutant strains.The three mutants and the wild type (B05.10) were grown in MB. 1 M sorbitol was added to the medium where indicated. A) Morphology under the microscope. B) Morphology under the scanning electron microscope.
Mentions: Microscopic observation of Δbcpmt mutants, grown in the chemically defined medium MB supplemented, or not, with 1 M Sorbitol, revealed big morphological changes in the hyphae of Δbcpmt2 and Δbcpmt4, especially the former (Figure 6). The most significant of these changes was the increase in the thickness of cells and the presence of balloon-like swollen cells in these two mutants, which partially disappear when 1 M sorbitol was included in the culture (Figure 6A). As discussed before, this can be explained by a softened cell wall not able to withstand the osmotic pressure. Similar morphologies have also been observed in pmt mutants in Asperglillus awamori[16], A. nidulans[33], [40], A. fumigatus[41] or Neurospora crassa[42]. Curiously, Δbcpmt2 also displayed a more frequent appearance of septa separating individual cells (Figure 6A), especially evident when staining with CW (not shown). The branching pattern was also different for Δbcpmt2 and Δbcpmt4, with a higher number of branching points in both of them (Figure 6B). Overall, it seems that Δbcpmt1 is morphologically similar to the wild type, Δbcpmt2 presents swollen, more frequently septated, and hyperbranched hyphae forming compact colonies, and Δbcpmt4 displays morphological characteristics which are intermediate between the wild type and Δbcpmt2. All these changes, with the clear exception of the increase in septum frequency, reverted with the addition of the osmotic stabilizer sorbitol, indicating that they are probably the consequence of the osmotic pressure acting on a weakened cell wall.

Bottom Line: The most significant case is that of grapevine leaves, whose penetration requires the three functional PMTs.Furthermore, PMT2 also contributes significantly to fungal adherence on grapevine and tobacco leaves.Analysis of extracellular and membrane proteins showed significant changes in the pattern of protein secretion and glycosylation by the pmt mutants, and allowed the identification of new protein substrates putatively glycosylated by specific PMTs.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de La Laguna, La Laguna (Tenerife), Spain.

ABSTRACT
Protein O-glycosylation is crucial in determining the structure and function of numerous secreted and membrane-bound proteins. In fungi, this process begins with the addition of a mannose residue by protein O-mannosyltransferases (PMTs) in the lumen side of the ER membrane. We have generated mutants of the three Botrytis cinerea pmt genes to study their role in the virulence of this wide-range plant pathogen. B. cinerea PMTs, especially PMT2, are critical for the stability of the cell wall and are necessary for sporulation and for the generation of the extracellular matrix. PMTs are also individually required for full virulence in a variety of hosts, with a special role in the penetration of intact plant leaves. The most significant case is that of grapevine leaves, whose penetration requires the three functional PMTs. Furthermore, PMT2 also contributes significantly to fungal adherence on grapevine and tobacco leaves. Analysis of extracellular and membrane proteins showed significant changes in the pattern of protein secretion and glycosylation by the pmt mutants, and allowed the identification of new protein substrates putatively glycosylated by specific PMTs. Since plants do no possess these enzymes, PMTs constitute a promising target in the development of novel control strategies against B. cinerea.

Show MeSH
Related in: MedlinePlus