scholarly journals Two softwood GUX clades are responsible for distinct glucuronic acid patterns on xylan

2021 ◽  
Author(s):  
Jan J Lyczakowski ◽  
Li Yu ◽  
Oliver M Terrett ◽  
Christina Fleischmann ◽  
Henry Temple ◽  
...  
Keyword(s):  
Cell Walls ◽  
Genetic Basis ◽  
Glucuronic Acid ◽  
Carbon Sink ◽  
Industrial Applications ◽  
Biomass Recalcitrance ◽  
In Planta ◽  
Cellulose Fibrils ◽  
Cell Wall Properties

AbstractWood of coniferous (softwood) trees, is a globally significant carbon sink and an important source of biomass for industrial applications. Despite its importance, very little is known about the genetic basis of softwood biosynthesis. Glucomannan and xylan are the main hemicelluloses in softwood secondary cell walls. Xylan interacts with the cellulose fibrils in a two-fold screw configuration. Moreover, we have shown that xylan GUX (GlucUronic acid substitution of Xylan)-dependent branching with glucuronic acid is critical for biomass recalcitrance. Here, we investigated the decoration patterns of xylan by softwood GUX enzymes. Using in vitro and in planta assays we demonstrate that two distinct clades of conifer GUX enzymes are active glucuronyltransferases. Interestingly, these enzymes have different specific activities, with one adding evenly spaced GlcA branches and the other one being also capable of glucuronidating two consecutive xyloses. Since xylan patterning might modulate xylan-cellulose and xylan-lignin interactions, our result further the understanding of softwood biosynthesis and can contribute to strategies aimed at modifying softwood cell wall properties.

scholarly journals The Yeast Signal Sequence Trap Identifies Secreted Proteins of the Hemibiotrophic Corn Pathogen Colletotrichum graminicola

2008 ◽  
Vol 21 (10) ◽  
pp. 1325-1336 ◽  
Author(s):  
Jorrit-Jan Krijger ◽  
Ralf Horbach ◽  
Michael Behr ◽  
Patrick Schweizer ◽  
Holger B. Deising ◽  
...  
Keyword(s):  
Cell Walls ◽  
Leaf Extract ◽  
Signal Sequence ◽  
Stem Rot ◽  
Colletotrichum Graminicola ◽  
In Planta ◽  
Chain Reaction ◽  
Genes Encoding ◽  
Polymerase Chain

The hemibiotroph Colletotrichum graminicola is the causal agent of stem rot and leaf anthracnose on Zea mays. Following penetration of epidermal cells, the fungus enters a short biotrophic phase, followed by a destructive necrotrophic phase of pathogenesis. During both phases, secreted fungal proteins are supposed to determine progress and success of the infection. To identify genes encoding such proteins, we constructed a yeast signal sequence trap (YSST) cDNA-library from RNA extracted from mycelium grown in vitro on corn cell walls and leaf extract. Of the 103 identified unigenes, 50 showed significant similarities to genes with a reported function, 25 sequences were similar to genes without a known function, and 28 sequences showed no similarity to entries in the databases. Macroarray hybridization and quantitative reverse-transcriptase polymerase chain reaction confirmed that most genes identified by the YSST screen are expressed in planta. Other than some genes that were constantly expressed, a larger set showed peaks of transcript abundances at specific phases of pathogenesis. Another set exhibited biphasic expression with peaks at the biotrophic and necrotrophic phase. Transcript analyses of in vitro-grown cultures revealed that several of the genes identified by the YSST screen were induced by the addition of corn leaf components, indicating that host-derived factors may have mimicked the host milieu.

scholarly journals Marine Macroalgae, a Source of Natural Inhibitors of Fungal Phytopathogens

2021 ◽  
Vol 7 (12) ◽  
pp. 1006
Author(s):  
Tânia F. L. Vicente ◽  
Marco F. L. Lemos ◽  
Rafael Félix ◽  
Patrícia Valentão ◽  
Carina Félix
Keyword(s):  
Fruits And Vegetables ◽  
Antimicrobial Agents ◽  
Industrial Applications ◽  
Marine Macroalgae ◽  
In Planta ◽  
Lipophilic Compounds ◽  
Wide Range ◽  
Fungal Phytopathogens

Fungal phytopathogens are a growing problem all over the world; their propagation causes significant crop losses, affecting the quality of fruits and vegetables, diminishing the availability of food, leading to the loss of billions of euros every year. To control fungal diseases, the use of synthetic chemical fungicides is widely applied; these substances are, however, environmentally damaging. Marine algae, one of the richest marine sources of compounds possessing a wide range of bioactivities, present an eco-friendly alternative in the search for diverse compounds with industrial applications. The synthesis of such bioactive compounds has been recognized as part of microalgal responsiveness to stress conditions, resulting in the production of polyphenols, polysaccharides, lipophilic compounds, and terpenoids, including halogenated compounds, already described as antimicrobial agents. Furthermore, many studies, in vitro or in planta, have demonstrated the inhibitory activity of these compounds with respect to fungal phytopathogens. This review aims to gather the maximum of information addressing macroalgae extracts with potential inhibition against fungal phytopathogens, including the best inhibitory results, while presenting some already reported mechanisms of action.

scholarly journals Immunochemical study of diverse surface antigens of a Staphylococcus aureus isolate from an osteomyelitis patient and their role in in vitro phagocytosis

1979 ◽  
Vol 9 (3) ◽  
pp. 399-408 ◽  
Author(s):  
W W Karakawa ◽  
D A Young
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Walls ◽  
Glucuronic Acid ◽  
Polymorphonuclear Cells ◽  
Wild Type ◽  
Phagocytic Cells ◽  
Immunochemical Study ◽  
Acidic Polysaccharide ◽  
Variant Strain

The cellular antigens of a strain of Staphylococcus aureus, isolated from a bone fragment from osteomyelitis, were analyzed immunochemically and by interaction with human phagocytic cells. When this strain was allowed to interact with human polymorphonuclear cells in the presence of antiserum, the strain was shown to have specific antiphagocytic antigens. An acidic polysaccharide consisting of galactose and glucuronic acid was isolated from the cell surface of the organism, and in vitro opsonization tests indicated that this acidic antigen impeded in vitro phagocytosis by human polymorphonuclear cells. It was also observed that antibodies directed against the mucopeptide constituents of homologous and heterologous bacterial cell walls were effective in promoting the in vitro opsonization of the organism. In the presence of antimucopeptide serum and human polymorphonuclear cells, a variant strain was isolated from the wild type, and immunochemical analysis indicated that this strain consisted of galactose and immunodominant amino-galacturonic acid residues. In vitro phagocytosis studies employing this variant strain indicated that the homologous human convalescent serum contained higher levels of opsonins against the variant strain than the original isolate, the wild type. This observation is discussed.

scholarly journals In vitro resynthesis of lichenization reveals the genetic background of symbiosis-specific fungal-algal interaction in Usnea hakonensis.

2020 ◽  
Author(s):  
Mieko Kono ◽  
Yoshiaki Kon ◽  
Yoshihito Ohmura ◽  
Yoko Satta ◽  
Yohey Terai
Keyword(s):  
Cell Walls ◽  
Genetic Background ◽  
Genetic Basis ◽  
Ecological Niches ◽  
Lichen Symbiosis ◽  
Fungal Partner ◽  
Wide Range ◽  
Photosynthetic Product ◽  
Lichen Thallus

Abstract Background Symbiosis often gives organisms the ability to expand ecological niches which are inaccessible as individuals. In lichen symbiosis, mutualistic relationships between lichen-forming fungi and algae and/or cyanobacteria produce unique features that make lichens adaptive to wide range of environments. This study revealed the fungal-algal interaction specific to the symbiosis in lichen using Usnea hakonensis as a model system. Results The whole genome of U. hakonensis, the fungal partner, was sequenced by using the culture isolated from a natural lichen thallus. Isolated cultures of the fungal and the algal partners were co-cultured in vitro for three months, and the thalli were successfully resynthesized into visible protrusions. Transcriptomes of resynthesized and natural thalli (symbiotic states) were compared to that of isolated cultures (non-symbiotic state). Sets of fungal and algal genes up-regulated in both symbiotic states were identified as symbiosis-related genes. Conclusion From the predicted functions of these genes, we identified the genetic background of two main features fundamental to the symbiotic lifestyle in lichen. First is an establishment of fungal symbiotic interface: (a) production of a hydrophobic layer that ensheaths fungal and algal cells; and (b) remodeling of cell walls at fungal-algal contact sites. Second is a symbiosis-specific nutrient flow: (a) the algal supply of photosynthetic product to the fungus; and (b) the fungal supply of phosphorous and nitrogen compounds to the alga. Since both features are widespread among lichens, our result may indicate the genetic basis of lichen symbiosis.

scholarly journals QTL mapping for aggressiveness variation in F. graminearum revealed one causal mutation in FgVe1 velvet protein

2020 ◽  
Author(s):  
B. Laurent ◽  
M. Moinard ◽  
C. Spataro ◽  
S. Chéreau ◽  
E. Zehraoui ◽  
...  
Keyword(s):  
Disease Severity ◽  
Protein Function ◽  
Genetic Basis ◽  
Disease Spread ◽  
In Planta ◽  
Head Blight ◽  
Phenotypic Differences ◽  
The World ◽  
Chromosome I

ABSTRACTFusarium graminearum is one of the most frequent causal agents of the Fusarium Head Blight in the world, a cereal disease spread throughout the world, reducing grain production and quality. F. graminearum isolates are genetically and phenotypically highly diverse. Notably, remarkable variations of aggressiveness between isolates have been observed, which could reflect an adaptive potential of this pathogen. In this study, we aimed to characterize the genetic basis of aggressiveness variation observed in an F1 population, for which genome sequences of both parental strains are available. Aggressiveness was assessed by a panel of in planta and in vitro proxies during two phenotyping trials including, among others, disease severity and mycotoxin accumulation in wheat spike. One major and single QTL was mapped for all the traits measured, on chromosome I, that explained up to 90% of the variance for disease severity. The confidence interval at the QTL spanned 1.2 Mb and contained 428 genes on the reference genome. Of these, four candidates were selected based on the postulate that a non-synonymous mutation affecting protein function may be responsible for phenotypic differences. Finally, a mutation was identified and functionally validated in the gene FgVe1, coding for a velvet protein known to be involved in pathogenicity and secondary metabolism production in several fungi.

scholarly journals Spontaneous in planta changes in fungal endophytes impact symbiosis

2007 ◽  
Vol 13 ◽  
pp. 191-193
Author(s):  
W.R. Simpson ◽  
M.J. Christensen ◽  
R.D. Johnson ◽  
J. Schmid
Keyword(s):  
Perennial Ryegrass ◽  
Cell Walls ◽  
Fungal Endophytes ◽  
Fungal Mycelium ◽  
Wild Type ◽  
In Planta ◽  
Neotyphodium Lolii ◽  
The Relationship ◽  
Host Tissues

The symbiosis between the asexual Ascomycetous fungi of the genus Neotyphodium and host grasses is considered to be symptomless. Symbioses involving Epichloë can show symptoms but this is restricted to the formation of stroma on floral structures. Fungal mycelium of both Epichloë and Neotyphodium endophytes occupy the intercellular space of plant tissues with no breach of host cell walls. Research involving these endophytes and their host grass symbioses relies on staining of host tissues and microscopic examination, immuno-detection or in-vitro isolation to determine infection status. This work reports on the observation of two independent instances of spontaneous change in the endophyte fungus that manifests as changes in the host grass vegetative morphology; one involving a genetically modified Epichloë festucae inoculated into a perennial ryegrass (Lolium perenne) population and the other a resident wild type Neotyphodium lolii. The relationship between wild type and variant fungus is confirmed as is the connection between variant fungus and host morphology. This work demonstrates that spontaneous in-planta changes in fungal endophytes occur and that these can impact on fungus/host grass symbioses. Keywords: Neotyphodium, Epichloë, symbiosis, endophyte, perennial ryegrass

Methods of experimental polyploidization and their use in apple breeding

2020 ◽  
Vol 62 ◽  
pp. 85-90
Author(s):  
L. V. Tashmatova ◽  
O. V. Matsneva ◽  
T. M. Khromova ◽  
V. V. Shakhov
Keyword(s):  
Exposure Time ◽  
Cell Walls ◽  
Prolonged Exposure ◽  
Ornamental Plants ◽  
Colchicine Treatment ◽  
Apple Trees ◽  
Open Ground ◽  
High Concentrations ◽  
Diploid Gametes

The article presents methods of experimental polyploidy of fruit, berry and ornamental plants. The purpose of this review is to highlight the problems and prospects of polyploidization of plants in the open ground and in vitro culture and the possibility of their application for apple trees. For the purpose of obtaining apple tetraploids as donors of diploid gametes, seed seedlings were treated with a solution of colchicine in concentrations of 0.1-0.4 % for 24 and 48 hours. Colchicine concentrations of 0.3 % and 0.4 % at 48 hours of treatment had a detrimental eff ect on their development. As a result, tetraploids and chimeras were obtained from seeds from free pollination of the varieties Orlik, Svezhest, Kandil Orlovsky, as well as from seeds obtained from crossing the varieties Svezhest×Bolotovskoe, Moskovskoe Оzherel’e×Imrus, Girlyanda×Venyaminovskoe. The optimal concentration of colchicine was 0.1 %. Methods of colchicine treatment have been studied: 1) adding to the nutrient medium, colchicine concentration: 0.01%, 0.02%, exposure time 24h-19 days; 2) applying amitotic solution to the growth point, colchicine concentration: 0.1 %, 0.2 %, exposure time 24h-7 days. To increase the penetration of colchicine through the cell walls, a 0.1 % dimexide solution was used. Studies have shown that high concentrations and prolonged exposure to colchicine reduce the viability of explants.

Enzyme Promiscuous Activity: How to Define it and its Evolutionary Aspects

2020 ◽  
Vol 27 (5) ◽  
pp. 400-410
Author(s):  
Valentina De Luca ◽  
Luigi Mandrich
Keyword(s):  
Gene Evolution ◽  
Sequence Divergence ◽  
High Specificity ◽  
Industrial Applications ◽  
Point Of View ◽  
Enzyme Promiscuity ◽  
Primary Activity ◽  
Starting Point ◽  
Main Activity

: Enzymes are among the most studied biological molecules because better understanding enzymes structure and activity will shed more light on their biological processes and regulation; from a biotechnological point of view there are many examples of enzymes used with the aim to obtain new products and/or to make industrial processes less invasive towards the environment. Enzymes are known for their high specificity in the recognition of a substrate but considering the particular features of an increasing number of enzymes this is not completely true, in fact, many enzymes are active on different substrates: this ability is called enzyme promiscuity. Usually, promiscuous activities have significantly lower kinetic parameters than to that of primary activity, but they have a crucial role in gene evolution. It is accepted that gene duplication followed by sequence divergence is considered a key evolutionary mechanism to generate new enzyme functions. In this way, promiscuous activities are the starting point to increase a secondary activity in the main activity and then get a new enzyme. The primary activity can be lost or reduced to a promiscuous activity. In this review we describe the differences between substrate and enzyme promiscuity, and its rule in gene evolution. From a practical point of view the knowledge of promiscuity can facilitate the in vitro progress of proteins engineering, both for biomedical and industrial applications. In particular, we report cases regarding esterases, phosphotriesterases and cytochrome P450.

Antifungal Proteins from Plant Latex

2020 ◽  
Vol 21 (5) ◽  
pp. 497-506
Author(s):  
Mayck Silva Barbosa ◽  
Bruna da Silva Souza ◽  
Ana Clara Silva Sales ◽  
Jhoana D’arc Lopes de Sousa ◽  
Francisca Dayane Soares da Silva ◽  
...  
Keyword(s):  
Cell Walls ◽  
Defense Mechanisms ◽  
Hydrolytic Enzymes ◽  
Fungal Species ◽  
Biologically Active ◽  
Protein Classification ◽  
Fungal Cell ◽  
Antifungal Proteins ◽  
Plant Latex

Latex, a milky fluid found in several plants, is widely used for many purposes, and its proteins have been investigated by researchers. Many studies have shown that latex produced by some plant species is a natural source of biologically active compounds, and many of the hydrolytic enzymes are related to health benefits. Research on the characterization and industrial and pharmaceutical utility of latex has progressed in recent years. Latex proteins are associated with plants’ defense mechanisms, against attacks by fungi. In this respect, there are several biotechnological applications of antifungal proteins. Some findings reveal that antifungal proteins inhibit fungi by interrupting the synthesis of fungal cell walls or rupturing the membrane. Moreover, both phytopathogenic and clinical fungal strains are susceptible to latex proteins. The present review describes some important features of proteins isolated from plant latex which presented in vitro antifungal activities: protein classification, function, molecular weight, isoelectric point, as well as the fungal species that are inhibited by them. We also discuss their mechanisms of action.

scholarly journals A peroxisomal β-oxidative pathway contributes to the formation of C6–C1 aromatic volatiles in poplar

2021 ◽  
Author(s):  
Nathalie D Lackus ◽  
Axel Schmidt ◽  
Jonathan Gershenzon ◽  
Tobias G Köllner
Keyword(s):  
Cinnamic Acid ◽  
Aromatic Compounds ◽  
Populus Trichocarpa ◽  
Alternative Pathway ◽  
Gene Families ◽  
Defense Responses ◽  
In Planta ◽  
Black Cottonwood ◽  
Oxidative Pathway

AbstractBenzenoids (C6–C1 aromatic compounds) play important roles in plant defense and are often produced upon herbivory. Black cottonwood (Populus trichocarpa) produces a variety of volatile and nonvolatile benzenoids involved in various defense responses. However, their biosynthesis in poplar is mainly unresolved. We showed feeding of the poplar leaf beetle (Chrysomela populi) on P. trichocarpa leaves led to increased emission of the benzenoid volatiles benzaldehyde, benzylalcohol, and benzyl benzoate. The accumulation of salicinoids, a group of nonvolatile phenolic defense glycosides composed in part of benzenoid units, was hardly affected by beetle herbivory. In planta labeling experiments revealed that volatile and nonvolatile poplar benzenoids are produced from cinnamic acid (C6–C3). The biosynthesis of C6–C1 aromatic compounds from cinnamic acid has been described in petunia (Petunia hybrida) flowers where the pathway includes a peroxisomal-localized chain shortening sequence, involving cinnamate-CoA ligase (CNL), cinnamoyl-CoA hydratase/dehydrogenase (CHD), and 3-ketoacyl-CoA thiolase (KAT). Sequence and phylogenetic analysis enabled the identification of small CNL, CHD, and KAT gene families in P. trichocarpa. Heterologous expression of the candidate genes in Escherichia coli and characterization of purified proteins in vitro revealed enzymatic activities similar to those described in petunia flowers. RNA interference-mediated knockdown of the CNL subfamily in gray poplar (Populus x canescens) resulted in decreased emission of C6–C1 aromatic volatiles upon herbivory, while constitutively accumulating salicinoids were not affected. This indicates the peroxisomal β-oxidative pathway participates in the formation of volatile benzenoids. The chain shortening steps for salicinoids, however, likely employ an alternative pathway.

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