scholarly journals Chitinases Play a Key Role in Stipe Cell Wall Extension in the Mushroom Coprinopsis cinerea

2019 ◽  
Vol 85 (15) ◽  
Author(s):  
Jiangsheng Zhou ◽  
Liqin Kang ◽  
Cuicui Liu ◽  
Xin Niu ◽  
Xiaojun Wang ◽  
...  

ABSTRACT The elongation growth of the mushroom stipe is a characteristic but not well-understood morphogenetic event of basidiomycetes. We found that extending native stipe cell walls of Coprinopsis cinerea were associated with the release of N-acetylglucosamine and chitinbiose and with chitinase activity. Two chitinases among all detected chitinases from C. cinerea, ChiE1 and ChiIII, reconstituted heat-inactivated stipe wall extension and released N-acetylglucosamine and chitinbiose. Interestingly, both ChiE1 and ChiIII hydrolyze insoluble crystalline chitin powder, while other C. cinerea chitinases do not, suggesting that crystalline chitin components of the stipe cell wall are the target of action for ChiE1 and ChiIII. ChiE1- or ChiIII-reconstituted heat-inactivated stipe walls showed maximal extension activity at pH 4.5, consistent with the optimal pH for native stipe wall extension in vitro; ChiE1- or ChiIII-reconstituted heat-inactivated stipe wall extension activities were associated with stipe elongation growth regions; and the combination of ChiE1 and ChiIII showed a synergism to reconstitute heat-inactivated stipe wall extension at a low action concentration. Field emission scanning electron microscopy (FESEM) images showed that the inner surface of acid-induced extended native stipe cell walls and ChiE1- or ChiIII-reconstituted extended heat-inactivated stipe cell walls exhibited a partially broken parallel microfibril architecture; however, these broken transversely arranged microfibrils were not observed in the unextended stipe cell walls that were induced by neutral pH buffer or heat inactivation. Double knockdown of ChiE1 and ChiIII resulted in the reduction of stipe elongation, mycelium growth, and heat-sensitive cell wall extension of native stipes. These results indicate a chitinase-hydrolyzing mechanism for stipe cell wall extension. IMPORTANCE A remarkable feature in the development of basidiomycete fruiting bodies is stipe elongation growth that results primarily from manifold cell elongation. Some scientists have suggested that stipe elongation is the result of enzymatic hydrolysis of cell wall polysaccharides, while other scientists have proposed the possibility that stipe elongation results from nonhydrolytic disruption of the hydrogen bonds between cell wall polysaccharides. Here, we show direct evidence for a chitinase-hydrolyzing mechanism of stipe cell wall elongation in the model mushroom Coprinopsis cinerea that is different from the expansin nonhydrolysis mechanism of plant cell wall extension. We presumed that in the growing stipe cell walls, parallel chitin microfibrils are tethered by β-1,6-branched β-1,3-glucans, and that the breaking of the tether by chitinases leads to separation of these microfibrils to increase their spacing for insertion of new synthesized chitin and β-1,3-glucans under turgor pressure in vivo.

2019 ◽  
Vol 85 (21) ◽  
Author(s):  
Liqin Kang ◽  
Jiangsheng Zhou ◽  
Rui Wang ◽  
Xingwei Zhang ◽  
Cuicui Liu ◽  
...  

ABSTRACT This study reports that a high concentration of the endo-β-1,3-glucanase ENG (200 μg ml−1) induced heat-inactivated stipe wall extension of Coprinopsis cinerea, whereas a high concentration of the extracellular β-glucosidase BGL2 (1,000 μg ml−1) did not; however, in combination, low concentrations of ENG (25 μg ml−1) and BGL2 (260 μg ml−1) induced heat-inactivated stipe cell wall extension. In contrast to the previously reported chitinase-reconstituted stipe wall extension, β-1,3-glucanase-reconstituted heat-inactivated stipe cell wall extension initially exhibited a fast extension rate that quickly decreased to zero after approximately 60 min; the stipe cell wall extension induced by a high concentration of β-1,3-glucanase did not result in stipe breakage during measurement, and the inner surfaces of glucanase-reconstituted extended cell walls still remained as amorphous matrices that did not appear to have been damaged. These distinctive features of the β-1,3-glucanase-reconstituted wall extension may be because chitin chains are cross-linked not only to the nonreducing termini of the side chains and the backbones of β-1,6 branched β-1,3-glucans but also to other polysaccharides. Remarkably, a low concentration of either the β-1,3-glucanase ENG or of chitinase ChiE1 did not induce heat-inactivated stipe wall extension, but a combination of these two enzymes, each at a low concentration, showed stipe cell wall extension activity that exhibited a steady and continuous wall extension profile. Therefore, we concluded that the stipe cell wall extension is the result of the synergistic actions of glucanases and chitinases. IMPORTANCE We previously reported that the chitinase could induce stipe wall extension and was involved in stipe elongation growth of the mushroom Coprinopsis cinerea. In this study, we explored that β-1,3-glucanase also induced stipe cell wall extension. Interestingly, the extension profile and extended ultra-architecture of β-1,3-glucanase-reconstituted stipe wall were different from those of chitinase-reconstituted stipe wall. However, β-1,3-glucanase cooperated with chitinase to induce stipe cell wall extension. The significance of this synergy between glucanases and chitinases is that it enables a low concentration of active enzymes to induce wall extension, and the involvement of β-1,3-glucanases is necessary for the cell wall remodeling and the addition of new β-glucans during stipe elongation growth.


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1263
Author(s):  
David Stuart Thompson ◽  
Azharul Islam

The extensibility of synthetic polymers is routinely modulated by the addition of lower molecular weight spacing molecules known as plasticizers, and there is some evidence that water may have similar effects on plant cell walls. Furthermore, it appears that changes in wall hydration could affect wall behavior to a degree that seems likely to have physiological consequences at water potentials that many plants would experience under field conditions. Osmotica large enough to be excluded from plant cell walls and bacterial cellulose composites with other cell wall polysaccharides were used to alter their water content and to demonstrate that the relationship between water potential and degree of hydration of these materials is affected by their composition. Additionally, it was found that expansins facilitate rehydration of bacterial cellulose and cellulose composites and cause swelling of plant cell wall fragments in suspension and that these responses are also affected by polysaccharide composition. Given these observations, it seems probable that plant environmental responses include measures to regulate cell wall water content or mitigate the consequences of changes in wall hydration and that it may be possible to exploit such mechanisms to improve crop resilience.


Author(s):  
Cuicui Liu ◽  
Jingjing Bi ◽  
Liqin Kang ◽  
Jiangsheng Zhou ◽  
Xiao Liu ◽  
...  

2020 ◽  
Vol 21 (15) ◽  
pp. 5322
Author(s):  
Nadezda Ibragimova ◽  
Natalia Mokshina ◽  
Marina Ageeva ◽  
Oleg Gurjanov ◽  
Polina Mikshina

The plant cell wall is a complex structure consisting of a polysaccharide network. The rearrangements of the cell wall during the various physiological reactions of plants, however, are still not fully characterized. Profound changes in cell wall organization are detected by microscopy in the phloem fibers of flax (Linum usitatissimum) during the restoration of the vertical position of the inclined stems. To characterize the underlying biochemical and structural changes in the major cell wall polysaccharides, we compared the fiber cell walls of non-inclined and gravistimulated plants by focusing mainly on differences in non-cellulosic polysaccharides and the fine cellulose structure. Biochemical analysis revealed a slight increase in the content of pectins in the fiber cell walls of gravistimulated plants as well as an increase in accessibility for labeling non-cellulosic polysaccharides. The presence of galactosylated xyloglucan in the gelatinous cell wall layer of flax fibers was demonstrated, and its labeling was more pronounced in the gravistimulated plants. Using solid state NMR, an increase in the crystallinity of the cellulose in gravistimulated plants, along with a decrease in cellulose mobility, was demonstrated. Thus, gravistimulation may affect the rearrangement of the cell wall, which can enable restoration in a vertical position of the plant stem.


2015 ◽  
Vol 82 (2) ◽  
pp. 680-688 ◽  
Author(s):  
Michelle S. F. Tan ◽  
Sadequr Rahman ◽  
Gary A. Dykes

ABSTRACTMinimally processed fresh produce has been implicated as a major source of foodborne microbial pathogens globally. These pathogens must attach to the produce in order to be transmitted. Cut surfaces of produce that expose cell walls are particularly vulnerable. Little is known about the roles that different structural components (cellulose, pectin, and xyloglucan) of plant cell walls play in the attachment of foodborne bacterial pathogens. Using bacterial cellulose-derived plant cell wall models, we showed that the presence of pectin alone or xyloglucan alone affected the attachment of threeSalmonella entericastrains (Salmonella entericasubsp.entericaserovar Enteritidis ATCC 13076,Salmonella entericasubsp.entericaserovar Typhimurium ATCC 14028, andSalmonella entericasubsp.indicaM4) andListeria monocytogenesATCC 7644. In addition, we showed that this effect was modulated in the presence of both polysaccharides. Assays using pairwise combinations ofS.Typhimurium ATCC 14028 andL. monocytogenesATCC 7644 showed that bacterial attachment to all plant cell wall models was dependent on the characteristics of the individual bacterial strains and was not directly proportional to the initial concentration of the bacterial inoculum. This work showed that bacterial attachment was not determined directly by the plant cell wall model or bacterial physicochemical properties. We suggest that attachment of theSalmonellastrains may be influenced by the effects of these polysaccharides on physical and structural properties of the plant cell wall model. Our findings improve the understanding of howSalmonella entericaandListeria monocytogenesattach to plant cell walls, which may facilitate the development of better ways to prevent the attachment of these pathogens to such surfaces.


2014 ◽  
Vol 81 (4) ◽  
pp. 1375-1386 ◽  
Author(s):  
Xin Dai ◽  
Yan Tian ◽  
Jinting Li ◽  
Xiaoyun Su ◽  
Xuewei Wang ◽  
...  

ABSTRACTThe bovine rumen represents a highly specialized bioreactor where plant cell wall polysaccharides (PCWPs) are efficiently deconstructed via numerous enzymes produced by resident microorganisms. Although a large number of fibrolytic genes from rumen microorganisms have been identified, it remains unclear how they are expressed in a coordinated manner to efficiently degrade PCWPs. In this study, we performed a metatranscriptomic analysis of the rumen microbiomes of adult Holstein cows fed a fiber diet and obtained a total of 1,107,083 high-quality non-rRNA reads with an average length of 483 nucleotides. Transcripts encoding glycoside hydrolases (GHs) and carbohydrate binding modules (CBMs) accounted for ∼1% and ∼0.1% of the total non-rRNAs, respectively. The majority (∼98%) of the putative cellulases belonged to four GH families (i.e., GH5, GH9, GH45, and GH48) and were primarily synthesized byRuminococcusandFibrobacter. Notably, transcripts for GH48 cellobiohydrolases were relatively abundant compared to the abundance of transcripts for other cellulases. Two-thirds of the putative hemicellulases were of the GH10, GH11, and GH26 types and were produced by members of the generaRuminococcus,Prevotella, andFibrobacter. Most (∼82%) predicted oligosaccharide-degrading enzymes were GH1, GH2, GH3, and GH43 proteins and were from a diverse group of microorganisms. Transcripts for CBM10 and dockerin, key components of the cellulosome, were also relatively abundant. Our results provide metatranscriptomic evidence in support of the notion that members of the generaRuminococcus,Fibrobacter, andPrevotellaare predominant PCWP degraders and point to the significant contribution of GH48 cellobiohydrolases and cellulosome-like structures to efficient PCWP degradation in the cow rumen.


2006 ◽  
Vol 18 (2) ◽  
pp. 325-331 ◽  
Author(s):  
Márcia Regina Braga ◽  
Nicholas C. Carpita ◽  
Sonia M. C. Dietrich ◽  
Rita de Cássia L. Figueiredo-Ribeiro

The thickened underground organ of Ocimum nudicaule is a tuber-like structure (xylopodium) that is dormant in winter and sprouts at the beginning of the spring. Changes in content of cell wall polysaccharides were shown to occur from dormancy to sprouting. Pectic polysaccharides of O. nudicaule were analyzed in relation to composition, molecular mass, and linkage structure in these two phenological phases. The pectin content was 33 % lower during sprouting when compared to dormancy. Changes were also observed in the molecular mass of the pectin fraction from dormancy to sprouting. Galacturonic acid was the predominant sugar, suggesting the presence of a homogalacturonan as the main pectic polysaccharide. A decrease in the acidic polysaccharides, homogalacturonans and rhamnogalacturonan I, equally accounted for the decrease in the pectin composition upon sprouting. These acidic carbohydrates were predominantly detected in the cell walls of the phellogen region of the xylopodium, suggesting catabolism of the cell walls of this tissue during bud flushing. These results suggest that variations in the content and in the molecular mass of pectins, in addition to changes in their composition and structure could be related to storage function as well as cell wall extension growth, both required for the sprouting of new buds in the xylopodium of O. nudicaule.


2019 ◽  
Vol 85 (14) ◽  
Author(s):  
Inger Skrede ◽  
Monica Hongrø Solbakken ◽  
Jaqueline Hess ◽  
Carl Gunnar Fossdal ◽  
Olav Hegnar ◽  
...  

ABSTRACT The aim of this study was to investigate differential expression profiles of the brown rot fungus Rhodonia placenta (previously Postia placenta) harvested at several time points when grown on radiata pine (Pinus radiata) and radiata pine with three different levels of modification by furfuryl alcohol, an environmentally benign commercial wood protection system. The entire gene expression pattern of a decay fungus was followed in untreated and modified wood from initial to advanced stages of decay. The results support the current model of a two-step decay mechanism, with the expression of genes related to initial oxidative depolymerization, followed by an accumulation of transcripts of genes related to the hydrolysis of cell wall polysaccharides. When the wood decay process is finished, the fungus goes into starvation mode after five weeks when grown on unmodified radiata pine wood. The pattern of repression of oxidative processes and oxalic acid synthesis found in radiata pine at later stages of decay is not mirrored for the high-furfurylation treatment. The high treatment level provided a more unpredictable expression pattern throughout the incubation period. Furfurylation does not seem to directly influence the expression of core plant cell wall-hydrolyzing enzymes, as a delayed and prolonged, but similar, pattern was observed in the radiata pine and the modified experiments. This indicates that the fungus starts a common decay process in the modified wood but proceeds at a slower pace as access to the plant cell wall polysaccharides is restricted. This is further supported by the downregulation of hydrolytic enzymes for the high treatment level at the last harvest point (mass loss, 14%). Moreover, the mass loss does not increase during the last weeks. Collectively, this indicates a potential threshold for lower mass loss for the high-furfurylation treatment. IMPORTANCE Fungi are important decomposers of woody biomass in natural habitats. Investigation of the mechanisms employed by decay fungi in their attempt to degrade wood is important for both the basic scientific understanding of ecology and carbon cycling in nature and for applied uses of woody materials. For wooden building materials, long service life and carbon storage are essential, but decay fungi are responsible for massive losses of wood in service. Thus, the optimization of durable wood products for the future is of major importance. In this study, we have investigated the fungal genetic response to furfurylated wood, a commercial environmentally benign wood modification approach that improves the service life of wood in outdoor applications. Our results show that there is a delayed wood decay by the fungus as a response to furfurylated wood, and new knowledge about the mechanisms behind the delay is provided.


2021 ◽  
Vol 22 (6) ◽  
pp. 3077
Author(s):  
Zhenzhen Hao ◽  
Xiaolu Wang ◽  
Haomeng Yang ◽  
Tao Tu ◽  
Jie Zhang ◽  
...  

Plant cell wall polysaccharides (PCWP) are abundantly present in the food of humans and feed of livestock. Mammalians by themselves cannot degrade PCWP but rather depend on microbes resident in the gut intestine for deconstruction. The dominant Bacteroidetes in the gut microbial community are such bacteria with PCWP-degrading ability. The polysaccharide utilization systems (PUL) responsible for PCWP degradation and utilization are a prominent feature of Bacteroidetes. In recent years, there have been tremendous efforts in elucidating how PULs assist Bacteroidetes to assimilate carbon and acquire energy from PCWP. Here, we will review the PUL-mediated plant cell wall polysaccharides utilization in the gut Bacteroidetes focusing on cellulose, xylan, mannan, and pectin utilization and discuss how the mechanisms can be exploited to modulate the gut microbiota.


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