| 1. |
- Chen, Hongxin, et al.
(författare)
-
A cerato-platanin-like protein HaCPL2 from Heterobasidion annosum sensu stricto induces cell death in Nicotiana tabacum and Pinus sylvestris
- 2015
-
Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1087-1845 .- 1096-0937. ; 84, s. 41-51
-
Tidskriftsartikel (refereegranskat)abstract
- The cerato-platanin family is a group of small secreted cysteine-rich proteins exclusive for filamentous fungi. They have been shown to be involved in the interactions between fungi and plants. Functional characterization of members from this family has been performed mainly in Ascomycota, except Moniliophthora perniciosa. Our previous phylogenetic analysis revealed that recent gene duplication of cerato-platanins has occurred in Basidiomycota but not in Ascomycota, suggesting higher functional diversification of this protein family in Basidiomycota than in Ascomycota. In this study, we identified three cerato-platanin homologues from the basidiomycete conifer pathogen Heterobasidion annosum sensu stricto. Expression of the homologues under various conditions as well as their roles in the H. annosum s.s.-Pinus sylvestris (Scots pine) pathosystem was investigated. Results showed that HaCPL2 (ceratoplatanin-like protein 2) had the highest sequence similarity to cerato-platanin from Ceratocystis platani and hacpl2 was significantly induced during nutrient starvation and necrotrophic growth. The treatment with recombinant HaCPL2 induced cell death, phytoalexin production and defense gene expression in Nicotiana tabacum. Eliciting and cell death-inducing ability accompanied by retardation of apical root growth was also demonstrated in Scots pine seedlings. Our results suggest that HaCPL2 might contribute to the virulence of H. annosum s.s. by promoting plant cell death.
|
|
| 2. |
- Dubey, Mukesh, et al.
(författare)
-
Disruption of the Eng18B ENGase Gene in the Fungal Biocontrol Agent Trichoderm atroviride Affetcs Growth Conidation and Antagonistic Ability
- 2012
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:5
-
Tidskriftsartikel (refereegranskat)abstract
- The recently identified phylogenetic subgroup B5 of fungal glycoside hydrolase family 18 genes encodes enzymes with mannosyl glycoprotein endo-N-acetyl-b-D-glucosaminidase (ENGase)-type activity. Intracellular ENGase activity is associated with the endoplasmic reticulum associated protein degradation pathway (ERAD) of misfolded glycoproteins, although the biological relevance in filamentous fungi is not known. Trichoderma atroviride is a mycoparasitic fungus that is used for biological control of plant pathogenic fungi. The present work is a functional study of the T. atroviride B5-group gene Eng18B, with emphasis on its role in fungal growth and antagonism. A homology model of T. atroviride Eng18B structure predicts a typical glycoside hydrolase family 18 (ab) 8 barrel architecture. Gene expression analysis shows that Eng18B is induced in dual cultures with the fungal plant pathogens Botrytis cinerea and Rhizoctonia solani, although a basal expression is observed in all growth conditions tested. Eng18B disruption strains had significantly reduced growth rates but higher conidiation rates compared to the wild-type strain. However, growth rates on abiotic stress media were significantly higher in Eng18B disruption strains compared to the wild-type strain. No difference in spore germination, germ-tube morphology or in hyphal branching was detected. Disruption strains produced less biomass in liquid cultures than the wild-type strain when grown with chitin as the sole carbon source. In addition, we determined that Eng18B is required for the antagonistic ability of T. atroviride against the grey mould fungus B. cinerea in dual cultures and that this reduction in antagonistic ability is partly connected to a secreted factor. The phenotypes were recovered by re-introduction of an intact Eng18B gene fragment in mutant strains. A putative role of Eng18B ENGase activity in the endoplasmic reticulum associated protein degradation pathway of endogenous glycoproteins in T. atroviride is discussed in relation to the observed phenotypes.
|
|
| 3. |
- Dubey, Mukesh, et al.
(författare)
-
The glyoxylate cycle is involved in pleotropic phenotypes, antagonism and induction of plant defence responses in the fungal biocontrol agent Trichoderma atroviride
- 2013
-
Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1087-1845 .- 1096-0937. ; 58-59, s. 33-41
-
Tidskriftsartikel (refereegranskat)abstract
- Isocitrate lyase (ICL), a signature enzyme of the glyoxylate cycle, is required for metabolism of non-fermentable carbon compounds like acetate or ethanol, and virulence in bacteria and fungi. In the present study, we investigate the role of the glyoxylate cycle in the fungal biocontrol agent Trichoderma atroviride by generating id deletion and complementation mutants. Phenotypic analyses of the deletion mutant Delta icl suggest that ICL is required for normal growth, conidial pigmentation and germination, and abiotic stress tolerance. The Delta icl strain display reduced antagonism towards Botrytis cinerea in plate confrontation assays. Secretion and sandwich assays further show that secreted factors are partly responsible for the reduced antagonism. Furthermore, in vitro root colonization assays shows that the Delta icl strain retains the ability to internally colonize Arabidopsis thaliana roots. However, the Delta icl strain has a reduced ability to induce systemic defence in A. thaliana leaves that results in reduced protection against B. cinerea. These data shows that ICL and the glyoxylate cycle are important for biocontrol traits in T. atroviride, including direct antagonism and induction of defence responses in plants.
|
|
| 4. |
|
|
| 5. |
- Haddad Momeni, Majid, et al.
(författare)
-
Structural insights into the inhibition of cellobiohydrolase Cel7A by xylo-oligosaccharides
- 2015
-
Ingår i: The FEBS Journal. - : Wiley. - 1742-464X. ; 282:11, s. 2167-2177
-
Tidskriftsartikel (refereegranskat)abstract
- The filamentous fungus Hypocreajecorina (anamorph of Trichodermareesei) is the predominant source of enzymes for industrial saccharification of lignocellulose biomass. The major enzyme, cellobiohydrolase Cel7A, constitutes nearly half of the total protein in the secretome. The performance of such enzymes is susceptible to inhibition by compounds liberated by physico-chemical pre-treatment if the biomass is kept unwashed. Xylan and xylo-oligosaccharides (XOS) have been proposed to play a key role in inhibition of cellobiohydrolases of glycoside hydrolase family7. To elucidate the mechanism behind this inhibition at a molecular level, we used X-ray crystallography to determine structures of H.jecorina Cel7A in complex with XOS. Structures with xylotriose, xylotetraose and xylopentaose revealed a predominant binding mode at the entrance of the substrate-binding tunnel of the enzyme, in which each xylose residue is shifted similar to 2.4 angstrom towards the catalytic center compared with binding of cello-oligosaccharides. Furthermore, partial occupancy of two consecutive xylose residues at subsites -2 and -1 suggests an alternative binding mode for XOS in the vicinity of the catalytic center. Interestingly, the -1 xylosyl unit exhibits an open aldehyde conformation in one of the structures and a ring-closed pyranoside in another complex. Complementary inhibition studies with p-nitrophenyl lactoside as substrate indicate mixed inhibition rather than pure competitive inhibition. DatabaseThe atomic coordinates and structure factors are available in the Protein Data Bank under accession number (H. jecorina Cel7A E212Q variant, complex with xylotriose), (H. jecorina Cel7A E217Q variant, complex with xylotriose), (H. jecorina Cel7A E212Q variant, complex with xylopentaose), (H. jecorina Cel7A E217Q variant, complex with xylopentaose), (wild-type H. jecorina Cel7A, complex with xylopentaose) and (H. jecorina Cel7A E217Q variant, complex with xylotetraose).
|
|
| 6. |
- Ihrmark, Katarina, et al.
(författare)
-
Comparative Molecular Evolution of Trichoderma Chitinases in Response to Mycoparasitic Interactions
- 2010
-
Ingår i: Evolutionary Bioinformatics. - 1176-9343. ; 6, s. 1-25
-
Tidskriftsartikel (refereegranskat)abstract
- Certain species of the fungal genus Trichoderma are potent mycoparasites and are used for biological control of fungal diseases on agricultural crops. In Trichoderma, whole-genome sequencing reveal between 20 and 36 different genes encoding chitinases, hydrolytic enzymes that are involved in the mycoparasitic attack. Sequences of Trichoderma chitinase genes chi18-5, chi18-13, chi18-15 and chi18-17, which all exhibit specific expression during mycoparasitism-related conditions, were determined from up to 13 different taxa and studied with regard to their evolutionary patterns. Two of them, chi18-13 and chi18-17, are members of the B1/B2 chitinase subgroup that have expanded significantly in paralog number in mycoparasitic Hypocrea atroviridis and H. virens. Chi18-13 contains two codons that evolve under positive selection and seven groups of co-evolving sites. Chi18-15 displays a unique codon-usage and contains five codons that evolve under positive selection and three groups of co-evolving sites. Regions of high amino acid variability are preferentially localized to substrate-or product side of the catalytic clefts. Differences in amino acid diversity/conservation patterns between different Trichoderma clades are observed. These observations show that Trichoderma chitinases chi18-13 and chi18-15 evolve in a manner consistent with rapid co-evolutionary interactions and identifies putative target regions involved in determining substrate-specificity.
|
|
| 7. |
- Jiang, Wanghsu, et al.
(författare)
-
MrpH, a new class of metal-binding adhesin, requires zinc to mediate biofilm formation
- 2020
-
Ingår i: PLoS Pathogens. - : PUBLIC LIBRARY SCIENCE. - 1553-7366 .- 1553-7374. ; 16:8
-
Tidskriftsartikel (refereegranskat)abstract
- Author summary Many bacteria use fimbriae to adhere to surfaces, and this function is often essential for pathogens to gain a foothold in the host. In this study, we examine the major virulence-associated fimbrial protein, MrpH, of the bacterial urinary tract pathogenProteus mirabilis. This species is particularly known for causing catheter-associated urinary tract infections, in which it forms damaging urinary stones and crystalline biofilms that can block the flow of urine through indwelling catheters. MrpH resides at the tip of mannose-resistantProteus-like (MR/P) fimbriae and is required for MR/P-dependent adherence to surfaces. Although MR/P belongs to a well-known class of adhesive fimbriae encoded by the chaperone-usher pathway, we found that MrpH has a dramatically different structure compared with other tip-located adhesins in this family. Unexpectedly, MrpH was found to bind a zinc cation, which we show is essential for MR/P-mediated biofilm formation and adherence to red blood cells. Furthermore, MR/P-mediated adherence can be modified by controlling zinc levels. These findings have the potential to aid development of better anti-biofilm urinary catheters or other methods to preventP.mirabilisinfection of the urinary tract. Proteus mirabilis, a Gram-negative uropathogen, is a major causative agent in catheter-associated urinary tract infections (CAUTI). Mannose-resistantProteus-like fimbriae (MR/P) are crucially important forP.mirabilisinfectivity and are required for biofilm formation and auto-aggregation, as well as for bladder and kidney colonization. Here, the X-ray crystal structure of the MR/P tip adhesin, MrpH, is reported. The structure has a fold not previously described and contains a transition metal center with Zn(2+)coordinated by three conserved histidine residues and a ligand. Using biofilm assays, chelation, metal complementation, and site-directed mutagenesis of the three histidines, we show that an intact metal binding site occupied by zinc is essential for MR/P fimbria-mediated biofilm formation, and furthermore, thatP.mirabilisbiofilm formation is reversible in a zinc-dependent manner. Zinc is also required for MR/P-dependent agglutination of erythrocytes, and mutation of the metal binding site rendersP.mirabilisunfit in a mouse model of UTI. The studies presented here provide important clues as to the mechanism of MR/P-mediated biofilm formation and serve as a starting point for identifying the physiological MR/P fimbrial receptor.
|
|
| 8. |
- Jiang, Wangshu, et al.
(författare)
-
Structural basis for MrpH-dependent Proteus mirabilis biofilm formation
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Proteus mirabilis is a Gram-negative uropathogen and the major causative agent in catheter-associated (CAUTI) and complicated UTIs. Mannose resistant Proteus-like fimbriae (MR/P) are crucially important for P. mirabilis infectivity and are required for biofilm formation and auto-aggregation, as well as for bladder and kidney colonisation. Here, the X-ray structure of the MR/P tip-located MrpH adhesin is reported. The structure has an unusual fold not previously observed, and contains a transition metal centre with Cu2+ or Zn2+ ligated by three conserved histidine residues and a ligand. Using metal complementation biofilm assays and site directed mutagenesis of the three histidines we show that an intact metal binding site occupied by zinc or copper is essential for MR/P-mediated biofilm formation. The studies presented here provide important clues as to the mechanism of MR/P-mediated biofilm formation and will serve as a starting point for identifying the physiological MR/P receptor(s).
|
|
| 9. |
- Jiang, Wangshu, et al.
(författare)
-
Structures of two fimbrial adhesins, AtfE and UcaD, from the uropathogen Proteus mirabilis
- 2018
-
Ingår i: Acta Crystallographica Section D. - 2059-7983. ; 74:Pt 11, s. 1053-1062
-
Tidskriftsartikel (refereegranskat)abstract
- The important uropathogen Proteus mirabilis encodes a record number of chaperone/usher-pathway adhesive fimbriae. Such fimbriae, which are used for adhesion to cell surfaces/tissues and for biofilm formation, are typically important virulence factors in bacterial pathogenesis. Here, the structures of the receptor-binding domains of the tip-located two-domain adhesins UcaD (1.5 Å resolution) and AtfE (1.58 Å resolution) from two P. mirabilis fimbriae (UCA/NAF and ATF) are presented. The structures of UcaD and AtfE are both similar to the F17G type of tip-located fimbrial receptor-binding domains, and the structures are very similar despite having only limited sequence similarity. These structures represent an important step towards a molecular-level understanding of P. mirabilis fimbrial adhesins and their roles in the complex pathogenesis of urinary-tract infections.
|
|
| 10. |
|
|
