scholarly journals Genomes and secretomes of Ascomycota fungi reveal diverse functions in plant biomass decomposition and pathogenesis

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Jean F. Challacombe ◽  
Cedar N. Hesse ◽  
Lisa M. Bramer ◽  
Lee Ann McCue ◽  
Mary Lipton ◽  
...  

Abstract Background The dominant fungi in arid grasslands and shrublands are members of the Ascomycota phylum. Ascomycota fungi are important drivers in carbon and nitrogen cycling in arid ecosystems. These fungi play roles in soil stability, plant biomass decomposition, and endophytic interactions with plants. They may also form symbiotic associations with biocrust components or be latent saprotrophs or pathogens that live on plant tissues. However, their functional potential in arid soils, where organic matter, nutrients and water are very low or only periodically available, is poorly characterized. Results Five Ascomycota fungi were isolated from different soil crust microhabitats and rhizosphere soils around the native bunchgrass Pleuraphis jamesii in an arid grassland near Moab, UT, USA. Putative genera were Coniochaeta, isolated from lichen biocrust, Embellisia from cyanobacteria biocrust, Chaetomium from below lichen biocrust, Phoma from a moss microhabitat, and Aspergillus from the soil. The fungi were grown in replicate cultures on different carbon sources (chitin, native bunchgrass or pine wood) relevant to plant biomass and soil carbon sources. Secretomes produced by the fungi on each substrate were characterized. Results demonstrate that these fungi likely interact with primary producers (biocrust or plants) by secreting a wide range of proteins that facilitate symbiotic associations. Each of the fungal isolates secreted enzymes that degrade plant biomass, small secreted effector proteins, and proteins involved in either beneficial plant interactions or virulence. Aspergillus and Phoma expressed more plant biomass degrading enzymes when grown in grass- and pine-containing cultures than in chitin. Coniochaeta and Embellisia expressed similar numbers of these enzymes under all conditions, while Chaetomium secreted more of these enzymes in grass-containing cultures. Conclusions This study of Ascomycota genomes and secretomes provides important insights about the lifestyles and the roles that Ascomycota fungi likely play in arid grassland, ecosystems. However, the exact nature of those interactions, whether any or all of the isolates are true endophytes, latent saprotrophs or opportunistic phytopathogens, will be the topic of future studies.

Fermentation ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 124
Author(s):  
Dung Minh Ha-Tran ◽  
Trinh Thi My Nguyen ◽  
Chieh-Chen Huang

Bioethanol is considered an excellent alternative to fossil fuels, since it importantly contributes to the reduced consumption of crude oil, and to the alleviation of environmental pollution. Up to now, the baker yeast Saccharomyces cerevisiae is the most common eukaryotic microorganism used in ethanol production. The inability of S. cerevisiae to grow on pentoses, however, hinders its effective growth on plant biomass hydrolysates, which contain large amounts of C5 and C12 sugars. The industrial-scale bioprocessing requires high temperature bioreactors, diverse carbon sources, and the high titer production of volatile compounds. These criteria indicate that the search for alternative microbes possessing useful traits that meet the required standards of bioethanol production is necessary. Compared to other yeasts, Kluyveromyces marxianus has several advantages over others, e.g., it could grow on a broad spectrum of substrates (C5, C6 and C12 sugars); tolerate high temperature, toxins, and a wide range of pH values; and produce volatile short-chain ester. K. marxianus also shows a high ethanol production rate at high temperature and is a Crabtree-negative species. These attributes make K. marxianus promising as an industrial host for the biosynthesis of biofuels and other valuable chemicals.


Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 530 ◽  
Author(s):  
Bao-Teng Wang ◽  
Shuang Hu ◽  
Xing-Ye Yu ◽  
Long Jin ◽  
Yun-Jia Zhu ◽  
...  

Polysaccharides are biopolymers made up of a large number of monosaccharides joined together by glycosidic bonds. Polysaccharides are widely distributed in nature: Some, such as peptidoglycan and cellulose, are the components that make up the cell walls of bacteria and plants, and some, such as starch and glycogen, are used as carbohydrate storage in plants and animals. Fungi exist in a variety of natural environments and can exploit a wide range of carbon sources. They play a crucial role in the global carbon cycle because of their ability to break down plant biomass, which is composed primarily of cell wall polysaccharides, including cellulose, hemicellulose, and pectin. Fungi produce a variety of enzymes that in combination degrade cell wall polysaccharides into different monosaccharides. Starch, the main component of grain, is also a polysaccharide that can be broken down into monosaccharides by fungi. These monosaccharides can be used for energy or as precursors for the biosynthesis of biomolecules through a series of enzymatic reactions. Industrial fermentation by microbes has been widely used to produce traditional foods, beverages, and biofuels from starch and to a lesser extent plant biomass. This review focuses on the degradation and utilization of plant homopolysaccharides, cellulose and starch; summarizes the activities of the enzymes involved and the regulation of the induction of the enzymes in well-studied filamentous fungi.


2021 ◽  
Vol 12 ◽  
Author(s):  
Diana Naalden ◽  
Paula J. M. van Kleeff ◽  
Sarmina Dangol ◽  
Marieke Mastop ◽  
Rebecca Corkill ◽  
...  

The Bemisia tabaci species complex (whitefly) causes enormous agricultural losses. These phloem-feeding insects induce feeding damage and transmit a wide range of dangerous plant viruses. Whiteflies colonize a broad range of plant species that appear to be poorly defended against these insects. Substantial research has begun to unravel how phloem feeders modulate plant processes, such as defense pathways, and the central roles of effector proteins, which are deposited into the plant along with the saliva during feeding. Here, we review the current literature on whitefly effectors in light of what is known about the effectors of phloem-feeding insects in general. Further analysis of these effectors may improve our understanding of how these insects establish compatible interactions with plants, whereas the subsequent identification of plant defense processes could lead to improved crop resistance to insects. We focus on the core concepts that define the effectors of phloem-feeding insects, such as the criteria used to identify candidate effectors in sequence-mining pipelines and screens used to analyze the potential roles of these effectors and their targets in planta. We discuss aspects of whitefly effector research that require further exploration, including where effectors localize when injected into plant tissues, whether the effectors target plant processes beyond defense pathways, and the properties of effectors in other insect excretions such as honeydew. Finally, we provide an overview of open issues and how they might be addressed.


Author(s):  
Dung Minh Ha-Tran ◽  
Trinh Thi My Nguyen ◽  
Chieh-Chen Huang

Bioethanol has been considered as an excellent alternative to fossil fuels since it importantly contributes to the reduced consumption of the crude oil and to the alleviation of environmental pollution [1]. Up to now, the baker yeast Saccharomyces cerevisiae is the most common eukaryotic microorganism used in ethanol production. The inability of S. cerevisiae to grow on pentoses, however, hinders its effective growth on plant biomass hydrolysates, which contain large amounts of C5 and C12 sugars. The industrial-scale bioprocessing requires high temperature bioreactors, diverse carbon sources, and the high titer production of volatile compounds [2]. These criteria indicate that the search for alternative microbes possessing useful traits that meet the required standards of bioethanol production is necessary. Compared to other yeasts, Kluyveromyces marxianus has several advantages over the others, e.g. it could grow on a broad spectrum of substrates (C5, C6 and C12 sugars) [3], tolerate to high temperature, toxin [4,5] and a wide range of pH values [6], and produce volatile short-chain ester [2]. K. marxianus also shows a high ethanol production rate at high temperature and is a Crabtree-negative species [7]. These attributes make K. marxianus a promise as an industrial host for the biosynthesis of biofuels and other valuable chemicals.


Author(s):  
Alif Chebbi ◽  
Massimiliano Tazzari ◽  
Cristiana Rizzi ◽  
Franco Hernan Gomez Tovar ◽  
Sara Villa ◽  
...  

Abstract Within the circular economy framework, our study aims to assess the rhamnolipid production from winery and olive oil residues as low-cost carbon sources by nonpathogenic strains. After evaluating various agricultural residues from those two sectors, Burkholderia thailandensis E264 was found to use the raw soluble fraction of nonfermented (white) grape marcs (NF), as the sole carbon and energy source, and simultaneously, reducing the surface tension to around 35 mN/m. Interestingly, this strain showed a rhamnolipid production up to 1070 mg/L (13.37 mg/g of NF), with a higher purity, on those grape marcs, predominately Rha-Rha C14-C14, in MSM medium. On olive oil residues, the rhamnolipid yield of using olive mill pomace (OMP) at 2% (w/v) was around 300 mg/L (15 mg/g of OMP) with a similar CMC of 500 mg/L. To the best of our knowledge, our study indicated for the first time that a nonpathogenic bacterium is able to produce long-chain rhamnolipids in MSM medium supplemented with winery residues, as sole carbon and energy source. Key points • Winery and olive oil residues are used for producing long-chain rhamnolipids (RLs). • Both higher RL yields and purity were obtained on nonfermented grape marcs as substrates. • Long-chain RLs revealed stabilities over a wide range of pH, temperatures, and salinities


Author(s):  
Mamou Diallo ◽  
Servé W. M. Kengen ◽  
Ana M. López-Contreras

AbstractThe Clostridium genus harbors compelling organisms for biotechnological production processes; while acetogenic clostridia can fix C1-compounds to produce acetate and ethanol, solventogenic clostridia can utilize a wide range of carbon sources to produce commercially valuable carboxylic acids, alcohols, and ketones by fermentation. Despite their potential, the conversion by these bacteria of carbohydrates or C1 compounds to alcohols is not cost-effective enough to result in economically viable processes. Engineering solventogenic clostridia by impairing sporulation is one of the investigated approaches to improve solvent productivity. Sporulation is a cell differentiation process triggered in bacteria in response to exposure to environmental stressors. The generated spores are metabolically inactive but resistant to harsh conditions (UV, chemicals, heat, oxygen). In Firmicutes, sporulation has been mainly studied in bacilli and pathogenic clostridia, and our knowledge of sporulation in solvent-producing or acetogenic clostridia is limited. Still, sporulation is an integral part of the cellular physiology of clostridia; thus, understanding the regulation of sporulation and its connection to solvent production may give clues to improve the performance of solventogenic clostridia. This review aims to provide an overview of the triggers, characteristics, and regulatory mechanism of sporulation in solventogenic clostridia. Those are further compared to the current knowledge on sporulation in the industrially relevant acetogenic clostridia. Finally, the potential applications of spores for process improvement are discussed.Key Points• The regulatory network governing sporulation initiation varies in solventogenic clostridia.• Media composition and cell density are the main triggers of sporulation.• Spores can be used to improve the fermentation process.


2015 ◽  
Vol 23 (4) ◽  
pp. 461-479 ◽  
Author(s):  
Robie W. Macdonald ◽  
Zou Zou A. Kuzyk ◽  
Sophia C. Johannessen

The sediments of the pan-Arctic shelves contribute an important component to the Arctic Ocean ecosystem by providing a habitat for biota (benthos), a repository for organic and inorganic non-conservative substances entering or produced within the ocean, a reactor and source of transformed substances back to the water column, and a mechanism of burial. Sediments interact with ice, ocean, and the surrounding land over a wide range of space and time scales. We discuss the vulnerability of shelf sediment to changes in (i) organic carbon sources, (ii) pathways of sediment and organic carbon supply, and (iii) physical and biogeochemical alteration (diagenesis). Sedimentary environments of the shelves and basins are likely to exhibit a wide variance in their response to global change because of their wide variation in sediment sources, processes, and metabolic conditions. In particular, the Chukchi and Barents shelves are dominated by inflowing waters from oceans to the south, whereas the interior shelves are more closely tied to terrigenous sources due to river inflow and coastal erosion.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1492
Author(s):  
Francisco G. Blanco ◽  
Natalia Hernández ◽  
Virginia Rivero-Buceta ◽  
Beatriz Maestro ◽  
Jesús M. Sanz ◽  
...  

Bacterial biopolymers are naturally occurring materials comprising a wide range of molecules with diverse chemical structures that can be produced from renewable sources following the principles of the circular economy. Over the last decades, they have gained substantial interest in the biomedical field as drug nanocarriers, implantable material coatings, and tissue-regeneration scaffolds or membranes due to their inherent biocompatibility, biodegradability into nonhazardous disintegration products, and their mechanical properties, which are similar to those of human tissues. The present review focuses upon three technologically advanced bacterial biopolymers, namely, bacterial cellulose (BC), polyhydroxyalkanoates (PHA), and γ-polyglutamic acid (PGA), as models of different carbon-backbone structures (polysaccharides, polyesters, and polyamides) produced by bacteria that are suitable for biomedical applications in nanoscale systems. This selection models evidence of the wide versatility of microorganisms to generate biopolymers by diverse metabolic strategies. We highlight the suitability for applied sustainable bioprocesses for the production of BC, PHA, and PGA based on renewable carbon sources and the singularity of each process driven by bacterial machinery. The inherent properties of each polymer can be fine-tuned by means of chemical and biotechnological approaches, such as metabolic engineering and peptide functionalization, to further expand their structural diversity and their applicability as nanomaterials in biomedicine.


Author(s):  
Barbara Wrzesińska ◽  
Agnieszka Zmienko ◽  
Lam Dai Vu ◽  
Ive De Smet ◽  
Aleksandra Obrępalska-Stęplowska

Abstract Key message PSV infection changed the abundance of host plant’s transcripts and proteins associated with various cellular compartments, including ribosomes, chloroplasts, mitochondria, the nucleus and cytosol, affecting photosynthesis, translation, transcription, and splicing. Abstract Virus infection is a process resulting in numerous molecular, cellular, and physiological changes, a wide range of which can be analyzed due to development of many high-throughput techniques. Plant RNA viruses are known to replicate in the cytoplasm; however, the roles of chloroplasts and other cellular structures in the viral replication cycle and in plant antiviral defense have been recently emphasized. Therefore, the aim of this study was to analyze the small RNAs, transcripts, proteins, and phosphoproteins affected during peanut stunt virus strain P (PSV-P)–Nicotiana benthamiana interactions with or without satellite RNA (satRNA) in the context of their cellular localization or functional connections with particular cellular compartments to elucidate the compartments most affected during pathogenesis at the early stages of infection. Moreover, the processes associated with particular cell compartments were determined. The ‘omic’ results were subjected to comparative data analyses. Transcriptomic and small RNA (sRNA)–seq data were obtained to provide new insights into PSV-P–satRNA–plant interactions, whereas previously obtained proteomic and phosphoproteomic data were used to broaden the analysis to terms associated with cellular compartments affected by virus infection. Based on the collected results, infection with PSV-P contributed to changes in the abundance of transcripts and proteins associated with various cellular compartments, including ribosomes, chloroplasts, mitochondria, the nucleus and the cytosol, and the most affected processes were photosynthesis, translation, transcription, and mRNA splicing. Furthermore, sRNA-seq and phosphoproteomic analyses indicated that kinase regulation resulted in decreases in phosphorylation levels. The kinases were associated with the membrane, cytoplasm, and nucleus components.


BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 942-953
Author(s):  
Wan-Yu Liao ◽  
Yu-Chun Huang ◽  
Wei-Lin Chen ◽  
Cheng-Yu Chen ◽  
Chao-Hsun Yang

Lignocelluloses are comprised of cellulose, hemicellulose, and lignins, which constitute plant biomass. Since peroxidases can degrade lignins, the authors examined peroxidase Tfu-1649, which is secreted from the thermophilic actinomycetes, Thermobifida fusca BCRC 19214. After cultivating for 48 h, the culture broth accumulated 43.66 U/mL of peroxidase activity. The treatment of four types of lignocellulolytic byproducts, i.e., bagasse, corncob, pin sawdust, and Zizania latifolia Turcz husk, with Tfu-1649 alone increased the total phenolic compounds, with limited reducing sugars, but treatment with xylanase, Tfu-11, and peroxidase Tfu-1649 showed synergistic effects. Hence, the co-operative degradation of lignocelluloses by both peroxidase and xylanase could contribute to biomass decomposition and further applications in the agricultural and environmental industries.


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