The chemical ecology of lichen mycoparasites: a review

1995 ◽  
Vol 73 (S1) ◽  
pp. 603-608 ◽  
Author(s):  
James D. Lawrey
Keyword(s):  
Cell Wall ◽  
Secondary Metabolites ◽  
Key Words ◽  
Chemical Ecology ◽  
Laboratory Studies ◽  
Cell Wall Degrading Enzymes ◽  
Host Preferences ◽  
Defense Compounds ◽  
Lichenicolous Fungi ◽  
Unique Mode

Lichenicolous fungi colonize lichens to form a variety of biotrophic associations, and while some 300 genera and 1000 species have been recognized, almost nothing is known about their biology. The lichenicolous habit is an unusual one because lichens produce a variety of antibiotic secondary metabolites that are assumed to protect them from parasitic attack. This may explain why lichens are rarely parasitized in nature while nonlichen-forming Ascomycetes are frequently and extensively parasitized. Recent field and laboratory studies of lichen parasites from a number of fungal groups indicate that chemistry is indeed involved in these interactions. These results indicate that (i) lichenicolous taxa are better able to degrade lichens than related nonlichenicolous taxa, (ii) lichen parasites are generally tolerant of lichen secondary metabolites, (iii) this tolerance seems to be based in part on the ability of cell wall degrading enzymes of parasites to remain active in the presence of these lichen secondary metabolites, and (iv) the host preferences of some lichen parasites reflect these tolerances. Therefore, it appears likely that lichenicolous fungi, which have presumably had lengthy coevolutionary histories with lichens, have evolved a unique mode of nutrition that is based in part on an ability to tolerate lichen defense compounds. Key words: Hobsonia, lichens, lichenicolous fungi, Nectria, parasites.

scholarly journals Cell Wall-Deficient Bacteria as a Cause of Infections: A Review of the Clinical Significance

2005 ◽  
Vol 33 (1) ◽  
pp. 1-20 ◽  
Author(s):  
ME Onwuamaegbu ◽  
RA Belcher ◽  
C Soare
Keyword(s):  
Cell Wall ◽  
Key Words ◽  
Clinical Significance ◽  
Case Reports ◽  
Reference List ◽  
Laboratory Studies ◽  
Disease Outcomes ◽  
Disease Associations ◽  
Considerable Controversy ◽  
Widespread Belief

Cell wall-deficient bacteria (CWDB) are pleomorphic bacterial forms. These atypical organisms may occur naturally or they can be induced in the laboratory. Their presence has been known about for over a century, but a definite link to clinical disease outcomes has not been demonstrated. A number of case reports and laboratory studies suggest some disease associations, however. Considerable controversy surrounds the true relevance of CWDB to disease; there is a widespread belief that they may represent a response by the walled organism to adverse extracellular conditions like antibiotic pressure. This review looks at studies published between 1934 and 2003, which were identified by Dialog DataStar using the key words ‘cell wall deficient bacteria and clinical significance and infections’ and by further scanning the reference list at the end of the papers retrieved. We conclude that the evidence for the clinical significance of CWDB in disease is not compelling.

Le Stigmidium lecidellae sp.nov. et remarques sur le genre Stigmidium (champignons lichénicoles non lichénisés, Ascomycètes)

1995 ◽  
Vol 73 (4) ◽  
pp. 662-672 ◽  
Author(s):  
Claude Roux ◽  
Olivier Bricaud ◽  
Didier Le Coeur ◽  
Dagmar Triebel
Keyword(s):  
Cell Wall ◽  
Key Words ◽  
Cell Walls ◽  
Species Level ◽  
Lichenicolous Fungi ◽  
Cresyl Blue ◽  
Taxonomic Key

Stigmidium lecidellae Triebel, Roux et Le Coeur sp.nov., a mild pathogenic lichenicolous fungus growing on the apothecia of Lecidella elaeochroma (Ach.) M. Choisy is described in detail and compared with other species of Stigmidium that grow on the apothecia of the host. The staining of parts of cell walls with cresyl blue is constant at species level and, therefore, is taxonomically relevant in the genus Stigmidium. The dye also allows to distinguish some ultrastructural details of the vegetative hyphal cells, asci, and ascospores. Among the fungi species growing on the apothecia of lichens, three groups are distinguished on the basis of their hamathecial structure, one of which should be excluded from the genus Stigmidium and included in the genus Sphaerellothecium. A key to the determination of the species is presented. Key words: lichenicolous fungi, Stigmidium, Sphaerellothecium, taxonomy, taxonomic key, cell wall, staining reactions, hamathecium.

scholarly journals Mycoparasitism illuminated by genome sequencing and digital gene expression profiling of Coniothyrium minitans, an important biocontrol fungus of the plant pathogen Sclerotinia sclerotiorum

2019 ◽  
Author(s):  
Huizhang Zhao ◽  
Ting Zhou ◽  
Jiatao Xie ◽  
Jiasen Cheng ◽  
Tao Chen ◽  
...  
Keyword(s):  
Cell Wall ◽  
Secondary Metabolites ◽  
Sclerotinia Sclerotiorum ◽  
Plant Pathogen ◽  
Hydrolase Activity ◽  
Secretory Proteins ◽  
Peptidase Activity ◽  
Serine Hydrolase ◽  
Cell Wall Degrading Enzymes ◽  
Degrading Enzymes

Abstract BackgroundConiothyrium minitans is a mycoparasite of the notorious plant pathogen Sclerotinia sclerotiorum. To further understand the parasitism of C. minitans, here, we assembled and analyzed its genome by combining transcriptome data.ResultsThe genome of C. minitans strain ZS-1 was 39.77 Mb in 350 scaffolds. A total of 11437 predicted genes and proteins were annotated, and 30.8% of blast hits matched proteins encoded by Paraphaeosphaeria sporulosa, a worldwide soil fungus. The transcriptome of strain ZS-1 during the early interaction at 0 h, 4 h and 12 h with its host was analyzed. The detected expressed genes were involved in response to host defenses, including cell wall-degrading enzymes, transporters, secretory proteins and secondary metabolites. The fungal cell wall-degrading enzymes belonged to the GH16, GH18, and GH72 classes in CAZymes, and some were significantly up-regulated during mycoparasitism. Most of the monocarboxylate transporter genes of the major facilitator superfamily and all the detected ABC transporters, especially the heavy metal transporters, were significantly up-regulated. Approximately 8% of the 11437 proteins in C. minitans were predicted to be secretory proteins, with catalytic activity, hydrolase activity, peptidase activity and serine hydrolase activity enriched in molecular function. Most genes involved in serine hydrolase activity were significantly up-regulated during mycoparasitism.ConclusionThis assemble genome and genome-wide expression study demonstrate that the mycoparasitism process of C. minitans is complex and a series of genes or proteins would be deployed by C. minitans to invade successfully the host. Our study provides insights into the mechanisms of the mycoparasitism between C. minitans and S. sclerotiorum and clues to excavate active secondary metabolites from C. minitans.

scholarly journals Endophytic Bacteria From the Roots of the Medicinal Plant Alkanna tinctoria Tausch (Boraginaceae): Exploration of Plant Growth Promoting Properties and Potential Role in the Production of Plant Secondary Metabolites

2021 ◽  
Vol 12 ◽  
Author(s):  
Angélique Rat ◽  
Henry D. Naranjo ◽  
Nikos Krigas ◽  
Katerina Grigoriadou ◽  
Eleni Maloupa ◽  
...  
Keyword(s):  
Cell Wall ◽  
Secondary Metabolites ◽  
Plant Growth ◽  
Medicinal Plant ◽  
Endophytic Bacteria ◽  
Cell Wall Degrading Enzymes ◽  
Plant Growth Promoting ◽  
Alkanna Tinctoria ◽  
Growth Promoting

Alkannin and shikonin (A/S) are enantiomeric naphthoquinones produced in the roots of certain plants from the Boraginaceae family such as Lithospermum spp. and Alkanna spp. They possess antimicrobial, anti-tumoral and wound healing properties. The production of secondary metabolites by Alkanna tinctoria might be influenced by its endomicrobiome. To study the interaction between this medicinal plant and its bacterial endophytes, we isolated bacteria from the roots of wild growing Alkanna tinctoria collected near to Athens and Thessaloniki in Greece. Representative strains selected by MALDI-TOF mass spectrometry were identified by partial 16S rRNA gene sequence analysis. In total, 197 distinct phylotypes of endophytic bacteria were detected. The most abundant genera recovered were Pseudomonas, Xanthomonas, Variovorax, Bacillus, Inquilinus, Pantoea, and Stenotrophomonas. Several bacteria were then tested in vitro for their plant growth promoting activity and the production of cell-wall degrading enzymes. Strains of Pseudomonas, Pantoea, Bacillus and Inquilinus showed positive plant growth properties whereas those of Bacteroidetes and Rhizobiaceae showed pectinase and cellulase activity in vitro. In addition, bacterial responses to alkannin and shikonin were investigated through resistance assays. Gram negative bacteria were found to be resistant to the antimicrobial properties of A/S, whereas the Gram positives were sensitive. A selection of bacteria was then tested for the ability to induce A/S production in hairy roots culture of A. tinctoria. Four strains belonging to Chitinophaga sp., Allorhizobium sp., Duganella sp., and Micromonospora sp., resulted in significantly more A/S in the hairy roots than the uninoculated control. As these bacteria can produce cell-wall degrading enzymes, we hypothesize that the A/S induction may be related with the plant-bacteria interaction during colonization.

scholarly journals Valorization of sugarcane bagasse by chemical pretreatment and enzyme mediated deconstruction

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Vihang S. Thite ◽  
Anuradha S. Nerurkar
Keyword(s):  
Cell Wall ◽  
Sugarcane Bagasse ◽  
Structural Changes ◽  
Enzymatic Saccharification ◽  
Dry Weight ◽  
Gravimetric Analysis ◽  
Chemical Pretreatment ◽  
Cell Wall Degrading Enzymes ◽  
First Time ◽  
Soluble Components

Abstract After chemical pretreatment, improved amenability of agrowaste biomass for enzymatic saccharification needs an understanding of the effect exerted by pretreatments on biomass for enzymatic deconstruction. In present studies, NaOH, NH4OH and H2SO4 pretreatments effectively changed visible morphology imparting distinct fibrous appearance to sugarcane bagasse (SCB). Filtrate analysis after NaOH, NH4OH and H2SO4 pretreatments yielded release of soluble reducing sugars (SRS) in range of ~0.17–0.44%, ~0.38–0.75% and ~2.9–8.4% respectively. Gravimetric analysis of pretreated SCB (PSCB) biomass also revealed dry weight loss in range of ~25.8–44.8%, ~11.1–16.0% and ~28.3–38.0% by the three pretreatments in the same order. Release of soluble components other than SRS, majorly reported to be soluble lignins, were observed highest for NaOH followed by H2SO4 and NH4OH pretreatments. Decrease or absence of peaks attributed to lignin and loosened fibrous appearance of biomass during FTIR and SEM studies respectively further corroborated with our observations of lignin removal. Application of commercial cellulase increased raw SCB saccharification from 1.93% to 38.84%, 25.56% and 9.61% after NaOH, H2SO4 and NH4OH pretreatments. Structural changes brought by cell wall degrading enzymes were first time shown visually confirming the cell wall disintegration under brightfield, darkfield and fluorescence microscopy. The microscopic evidence and saccharification results proved that the chemical treatment valorized the SCB by making it amenable for enzymatic saccharification.

scholarly journals Understanding Rice-Magnaporthe Oryzae Interaction in Resistant and Susceptible Cultivars of Rice under Panicle Blast Infection Using a Time-Course Transcriptome Analysis

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 301
Author(s):  
Vishesh Kumar ◽  
Priyanka Jain ◽  
Sureshkumar Venkadesan ◽  
Suhas Gorakh Karkute ◽  
Jyotika Bhati ◽  
...  
Keyword(s):  
Cell Wall ◽  
Secondary Metabolites ◽  
Magnaporthe Oryzae ◽  
Transcriptome Analysis ◽  
Hormonal Regulation ◽  
Rice Blast ◽  
Blast Resistance ◽  
Differentially Expressed ◽  
Specific Response ◽  
Panicle Blast

Rice blast is a global threat to food security with up to 50% yield losses. Panicle blast is a more severe form of rice blast and the response of rice plant to leaf and panicle blast is distinct in different genotypes. To understand the specific response of rice in panicle blast, transcriptome analysis of blast resistant cultivar Tetep, and susceptible cultivar HP2216 was carried out using RNA-Seq approach after 48, 72 and 96 h of infection with Magnaporthe oryzae along with mock inoculation. Transcriptome data analysis of infected panicle tissues revealed that 3553 genes differentially expressed in HP2216 and 2491 genes in Tetep, which must be the responsible factor behind the differential disease response. The defense responsive genes are involved mainly in defense pathways namely, hormonal regulation, synthesis of reactive oxygen species, secondary metabolites and cell wall modification. The common differentially expressed genes in both the cultivars were defense responsive transcription factors, NBS-LRR genes, kinases, pathogenesis related genes and peroxidases. In Tetep, cell wall strengthening pathway represented by PMR5, dirigent, tubulin, cell wall proteins, chitinases, and proteases was found to be specifically enriched. Additionally, many novel genes having DOMON, VWF, and PCaP1 domains which are specific to cell membrane were highly expressed only in Tetep post infection, suggesting their role in panicle blast resistance. Thus, our study shows that panicle blast resistance is a complex phenomenon contributed by early defense response through ROS production and detoxification, MAPK and LRR signaling, accumulation of antimicrobial compounds and secondary metabolites, and cell wall strengthening to prevent the entry and spread of the fungi. The present investigation provided valuable candidate genes that can unravel the mechanisms of panicle blast resistance and help in the rice blast breeding program.

scholarly journals High-CO2 Treatment Prolongs the Postharvest Shelf Life of Strawberry Fruits by Reducing Decay and Cell Wall Degradation

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1649
Author(s):  
Hyang-Lan Eum ◽  
Seung-Hyun Han ◽  
Eun-Jin Lee
Keyword(s):  
Cell Wall ◽  
Shelf Life ◽  
Physiological Mechanism ◽  
Pectate Lyase ◽  
Pectin Methylesterase ◽  
Cell Wall Degradation ◽  
Cell Wall Degrading Enzymes ◽  
High Co2 ◽  
Genes Encoding ◽  
Co2 Treatment

Improved methods are needed to extend the shelf life of strawberry fruits. The objective of this study was to determine the postharvest physiological mechanism of high-CO2 treatment in strawberries. Harvested strawberries were stored at 10 °C after 3 h of exposure to a treatment with 30% CO2 or air. Pectin and gene expression levels related to cell wall degradation were measured to assess the high-CO2 effects on the cell wall and lipid metabolism. Strawberries subjected to high-CO2 treatment presented higher pectin content and firmness and lower decay than those of control fruits. Genes encoding cell wall-degrading enzymes (pectin methylesterase, polygalacturonase, and pectate lyase) were downregulated after high-CO2 treatment. High-CO2 induced the expression of oligogalacturonides, thereby conferring defense against Botrytis cinerea in strawberry fruits, and lowering the decay incidence at seven days after its inoculation. Our findings suggest that high-CO2 treatment can maintain strawberry quality by reducing decay and cell wall degradation.

Physiological Effect of Lichen Secondary Metabolites on the Lichen Parasite Marchandiomyces Corallinus

1999 ◽  
Vol 31 (3) ◽  
pp. 307-314 ◽  
Author(s):  
A. P. Torzilli ◽  
P. A. Mikelson ◽  
J. D. Lawrey
Keyword(s):  
Catalytic Activity ◽  
Phenolic Compounds ◽  
Secondary Metabolites ◽  
Host Preference ◽  
Secondary Compounds ◽  
Physiological Effect ◽  
Physiological Adaptation ◽  
Secondary Chemistry ◽  
Physiological Basis ◽  
Lichenicolous Fungi

AbstractIt has been suggested that the host specificity exhibited by some lichenicolous fungi depends on their ability to tolerate the secondary chemistry of potential host lichens. For example, the lichen parasite Marchandiomyces corallinus is able to degrade the tissues of the lichen Flavoparmelia baltimorensis irrespective of the presence or absence of endogenous phenolic compounds. In contrast, the degradation of tissues from the lichen Lasallia papulosa is suppressed when endogenous phenolics are not removed. We have investigated the physiological basis of this inhibition in order to understand more about how lichen chemistry infiuences host preference in lichenicolous fungi. Results showed that the secondary compounds from L. papulosa inhibit the overall growth of M. corallimis, but not the catalytic activity of its tissue-degrading polysaccharidases. This effect is different from that shown by another lichen parasite, Nectria parmeliae, where lichen compounds specifically inhibited polysaccharidase activity. Compared with the compounds of L. papulosa, the endogenous phenolics of F. baltimorensis inhibited the growth of M. corallimis substantially less and exhibited little or no inhibition of polysaccharidases. For M. corallimis, host preference appears to be associated with physiological adaptation to the chemistry of F. baltimorensis.

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