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Wang Y, Li D, Li Z, Cui Z, Ye X. Functional analysis of a novel endo-β-1,6-glucanase MoGlu16 and its application in detecting cell wall β-1,6-glucan of Magnaporthe oryzae. Front Microbiol 2024; 15:1429065. [PMID: 39027104 PMCID: PMC11254853 DOI: 10.3389/fmicb.2024.1429065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 06/25/2024] [Indexed: 07/20/2024] Open
Abstract
As an essential component of the fungal cell wall, β-1,6-glucan has an important role in the growth and development of fungi, but its distribution has not been investigated in Magnaporthe oryzae. Here, a novel β-1,6-glucanase from M. oryzae, MoGlu16, was cloned and expressed in Pichia pastoris. The enzyme was highly active on pustulan, with a specific activity of 219.0 U/mg at pH 5.0 and 50°C, and showed great selectivity for continuous β-1,6-glycosidic bonding polysaccharides. Based on this, β-1,6-glucan was selectively visualized in the vegetative hyphae, conidia and bud tubes of M. oryzae using a hydrolytically inactive GFP-tagged MoGlu16 with point mutations at the catalytic position (His-MoGlu16E236A-Gfp). The spore germination and appressorium formation were significantly inhibited after incubation of 105/ml conidia with 0.03 μg/μl MoGlu16. Mycelia treated with MoGlu16 produced reactive oxygen species and triggered the cell wall integrity pathway, increasing the expression levels of genes involved in cell wall polysaccharide synthesis. These results revealed that MoGlu16 participated in the remodeling of cell wall in M. oryzae, laying a foundation for the analysis of cell wall structure.
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Affiliation(s)
- Yanxin Wang
- College of Life Sciences of Liaocheng University, Liaocheng, China
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences of Nanjing Agricultural University, Nanjing, China
| | - Ding Li
- Jiangsu Academy of Agricultural Sciences, Institute of Veterinary Immunology & Engineering, Nanjing, China
| | - Zhoukun Li
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences of Nanjing Agricultural University, Nanjing, China
| | - Zhongli Cui
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences of Nanjing Agricultural University, Nanjing, China
| | - Xianfeng Ye
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences of Nanjing Agricultural University, Nanjing, China
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Wang R, Clarke BB, Belanger FC. Transcriptome Analysis of Choke Stroma and Asymptomatic Inflorescence Tissues Reveals Changes in Gene Expression in Both Epichloë festucae and Its Host Plant Festuca rubra subsp. rubra. Microorganisms 2019; 7:E567. [PMID: 31744076 PMCID: PMC6921078 DOI: 10.3390/microorganisms7110567] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/13/2019] [Accepted: 11/14/2019] [Indexed: 02/07/2023] Open
Abstract
Many cool-season grasses have symbiotic relationships with Epichloë (Ascomycota, Clavicipitaceae) fungal endophytes that inhabit the intercellular spaces of the above-ground parts of the host plants. The presence of the Epichloë endophytes is generally beneficial to the hosts due to enhanced tolerance to biotic and abiotic stresses conferred by the endophytes. Many Epichloë spp. are asexual, and those infections always remain asymptomatic. However, some Epichloë spp. have a sexual stage and produce a macroscopic fruiting body, a stroma, that envelops the developing inflorescence causing a syndrome termed "choke disease". Here, we report a fungal and plant gene expression analysis of choke stroma tissue and asymptomatic inflorescence tissue of Epichloë festucae-infected strong creeping red fescue (Festuca rubra subsp. rubra). Hundreds of fungal genes and over 10% of the plant genes were differentially expressed when comparing the two tissue types. The differentially expressed fungal genes in the choke stroma tissue indicated a change in carbohydrate and lipid metabolism, as well as a change in expression of numerous genes for candidate effector proteins. Plant stress-related genes were up-regulated in the stroma tissue, suggesting the plant host was responding to the epiphytic stage of E. festucae as a pathogen.
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Affiliation(s)
| | | | - Faith C. Belanger
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (R.W.); (B.B.C.)
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Wang D, Kim DH, Yun EJ, Park YC, Seo JH, Kim KH. The first bacterial β-1,6-endoglucanase from Saccharophagus degradans 2-40 T for the hydrolysis of pustulan and laminarin. Appl Microbiol Biotechnol 2017; 101:197-204. [PMID: 27521023 DOI: 10.1007/s00253-016-7753-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 07/21/2016] [Accepted: 07/27/2016] [Indexed: 10/21/2022]
Abstract
β-1,6-glucan is a polysaccharide found in brown macroalgae and fungal cell walls. In this study, a β-1,6-endoglucanase gene from Saccharophagus degradans 2-40T, gly30B, was cloned and overexpressed in Escherichia coli. Gly30B, which belongs to the glycoside hydrolase family 30 (GH30), was found to possess β-1,6-endoglucanase activity by hydrolyzing β-1,6-glycosidic linkages of pustulan (β-1,6-glucan derived from fungal cell walls) and laminarin (β-1,3-glucan with β-1,6-branchings, derived from brown macroalgae) to produce gentiobiose and glucose as the final products. The optimal pH and temperature for Gly30B activity were found to be pH 7.0 and 40 °C, respectively. The kinetic constants of Gly30B, V max, K M, and k cat were determined to be 153.8 U/mg protein, 24.2 g/L, and 135.6 s-1 for pustulan and 32.8 U/mg protein, 100.8 g/L, and 28.9 s-1 for laminarin, respectively. To our knowledge, Gly30B is the first β-1,6-endoglucanase characterized from bacteria. Gly30B can be used to hydrolyze β-1,6-glucans of brown algae or fungal cell walls for producing gentiobiose as a high-value sugar and glucose as a fermentable sugar.
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Affiliation(s)
- Damao Wang
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, South Korea
| | - Do Hyoung Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, South Korea
| | - Eun Ju Yun
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, South Korea
| | - Yong-Cheol Park
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul, 02707, South Korea
| | - Jin-Ho Seo
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, South Korea.
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Bassett SA, Johnson RD, Simpson WR, Laugraud A, Jordan TW, Bryan GT. Identification of a gene involved in the regulation of hyphal growth of Epichloë festucae during symbiosis. FEMS Microbiol Lett 2016; 363:fnw214. [PMID: 27624305 DOI: 10.1093/femsle/fnw214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2016] [Indexed: 11/12/2022] Open
Abstract
Secreted proteins, those involved in cell wall biogenesis, are likely to play a role in communication in the symbiotic interaction between the fungal endophyte Epichloë festucae with perennial ryegrass (Lolium perenne), particularly given the close association between fungal hyphae and the plant cell wall. Our hypothesis was that secreted proteins are likely to be responsible for establishing and maintaining a normal symbiotic relationship. We analyzed an endophyte EST database for genes with predicted signal peptide sequences. Here, we report the identification and characterization of rhgA; a gene involved in the regulation of hyphal growth in planta In planta analysis of ΔrhgA mutants showed that disruption of rhgA resulted in extensive unregulated hyphal growth. This phenotype was fully complemented by insertion of the rhgA gene and suggests that rhgA is important for maintaining normal hyphal growth during symbiosis.
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Affiliation(s)
- Shalome A Bassett
- Food & Bio-based Products Group, AgResearch Ltd., Grasslands Research Centre, Tennent Drive, Palmerston North 4442, New Zealand
| | - Richard D Johnson
- Forage Science Group, AgResearch Ltd, Grasslands Research Centre, Tennent Drive, Palmerston North 4442, New Zealand
| | - Wayne R Simpson
- Forage Science Group, AgResearch Ltd, Grasslands Research Centre, Tennent Drive, Palmerston North 4442, New Zealand
| | - Aurelie Laugraud
- Bioinformatics and Statistics Team, Lincoln Research Centre, Private Bag 4749, Christchurch 8140, New Zealand
| | - T William Jordan
- Centre for Biodiscovery, School of Biological Sciences, Victoria University of Wellington, Kelburn Campus, Wellington 6140, New Zealand
| | - Gregory T Bryan
- Forage Science Group, AgResearch Ltd, Grasslands Research Centre, Tennent Drive, Palmerston North 4442, New Zealand
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Guo J, McCulley RL, McNear DH. Tall fescue cultivar and fungal endophyte combinations influence plant growth and root exudate composition. FRONTIERS IN PLANT SCIENCE 2015; 6:183. [PMID: 25914697 PMCID: PMC4391242 DOI: 10.3389/fpls.2015.00183] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 03/06/2015] [Indexed: 05/09/2023]
Abstract
Tall fescue [Lolium arundinaceum (Schreb.)] is a cool-season perennial grass used in pastures throughout the Southeastern United States. The grass can harbor a shoot-specific fungal endophyte (Epichloë coenophiala) thought to provide the plant with enhanced resistance to biotic and abiotic stresses. Because alkaloids produced by the common variety of the endophyte cause severe animal health issues, focus has been on replacing the common-toxic strain with novel varieties that do not produce the mammal-toxic alkaloids but maintain abiotic and biotic stress tolerance benefits. Little attention has been given to the influence of the plant-fungal symbiosis on rhizosphere processes. Therefore, our objective was to study the influence of this relationship on plant biomass production and root exudate composition in tall fescue cultivars PDF and 97TF1, which were either not infected with the endophyte (E-), infected with the common toxic endophyte (CTE+) strain or with one of two novel endophytes (AR542E+, AR584E+). Plants were grown sterile for 3 weeks after which plant biomass, total organic carbon, total phenolic content and detailed chemical composition of root exudates were determined. Plant biomass production and exudate phenolic and organic carbon content were influenced by endophyte status, tall fescue cultivar, and their interaction. GC-TOF MS identified 132 compounds, including lipids, carbohydrates and carboxylic acids. Cluster analysis showed that the interaction between endophyte and cultivar resulted in unique exudate profiles. This is the first detailed study to assess how endophyte infection, notably with novel endophytes, and tall fescue cultivar interact to influence root exudate composition. Our results illustrate that tall fescue cultivar and endophyte status can influence plant growth and root exudate composition, which may help explain the observed influence of this symbiosis on rhizosphere biogeochemical processes.
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Affiliation(s)
- Jingqi Guo
- Rhizosphere Science Laboratory, Department of Plant and Soil Sciences, University of KentuckyLexington, KY, USA
| | - Rebecca L. McCulley
- Grassland Ecology Laboratory, Department of Plant and Soil Sciences, University of KentuckyLexington, KY, USA
| | - David H. McNear
- Rhizosphere Science Laboratory, Department of Plant and Soil Sciences, University of KentuckyLexington, KY, USA
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Tadych M, Bergen MS, White JF. Epichloë spp. associated with grasses: new insights on life cycles, dissemination and evolution. Mycologia 2014; 106:181-201. [PMID: 24877257 DOI: 10.3852/106.2.181] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Epichloë species with their asexual states are specialized fungi associated with cool-season grasses. they grow endophytically in tissues of aerial parts of host plants to form systemic and mostly asymptomatic associations. Their life cycles may involve vertical transmission through host seeds and/or horizontal transmission from one plant to other plants of the same species through fungal propagules. Vertical transmission has been well studied, but comparatively little research has been done on horizontal dissemination. The goal of this review is to provide new insights on modes of dissemination of systemic grass endophytes. The review addresses recent progress in research on (i) the process of growth of Epichloë endophytes in the host plant tissues, (ii) the types and development of reproductive structures of the endophyte, (iii) the role of the reproductive structures in endophyte dissemination and host plant infection processes and (iv) some ecological and evolutionary implications of their modes of dissemination. Research in the Epichloë grass endophytes has accelerated in the past 25 y and has demonstrated the enormous complexity in endophyte-grass symbioses. There still remain large gaps in our understanding of the role and functions of these fungi in agricultural systems and understanding the functions, ecology and evolution of these endophytes in natural grass populations.
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Rasmussen S, Liu Q, Parsons AJ, Xue H, Sinclair B, Newman JA. Grass-endophyte interactions: a note on the role of monosaccharide transport in the Neotyphodium lolii-Lolium perenne symbiosis. THE NEW PHYTOLOGIST 2012; 196:7-12. [PMID: 22803786 DOI: 10.1111/j.1469-8137.2012.04250.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Affiliation(s)
- Susanne Rasmussen
- AgResearch, Grasslands Research Centre, PB 11008, Palmerston North, New Zealand
- (Author for correspondence: tel +64 6 351 8182; email )
| | - Qianhe Liu
- AgResearch, Grasslands Research Centre, PB 11008, Palmerston North, New Zealand
| | - Anthony J Parsons
- Institute of Natural Resources, Massey University, Palmerston North, New Zealand
| | - Hong Xue
- AgResearch, Grasslands Research Centre, PB 11008, Palmerston North, New Zealand
| | - Bruce Sinclair
- AgResearch, Grasslands Research Centre, PB 11008, Palmerston North, New Zealand
| | - Jonathan A Newman
- School of Environmental Sciences, University of Guelph, Guelph, ON, Canada N1G 2W1
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Konno N, Sakamoto Y. An endo-β-1,6-glucanase involved in Lentinula edodes fruiting body autolysis. Appl Microbiol Biotechnol 2011; 91:1365-73. [PMID: 21523473 DOI: 10.1007/s00253-011-3295-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 03/28/2011] [Accepted: 03/29/2011] [Indexed: 11/30/2022]
Abstract
A β-1,6-glucanase, LePus30A, was purified and cloned from fruiting bodies of the basidiomycete Lentinula edodes. β-1,6-glucanases degrade β-1,6-glucan polysaccharides, a unique and essential component of fungal cell walls. The complementary DNA of LePus30A includes an open reading frame of 1,575 bp encoding an 18 amino acid signal peptide and the 506 amino acid mature protein. Sequence analysis indicated that LePus30A is a member of glycoside hydrolase family 30, and highly similar genes are broadly conserved among basidiomycetes. The purified LePus30A catalyzed depolymerization of β-1,6-glucan endolytically and was highly specific toward β-1,6-glucan polysaccharide. It is known that the cell walls of fruiting bodies of basidiomycetes are autodegraded after harvesting by means of enzymatic hydrolysis. The transcript level of LePus30A gene (lepus30a) was significantly increased in fruiting bodies after harvesting. Moreover, LePus30A showed hydrolyzing activity against the cell wall components of L. edodes fruiting bodies. These results suggest that LePus30A is responsible for the degradation of the cell wall components during fruiting body autolysis after harvest.
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Affiliation(s)
- Naotake Konno
- Iwate Biotechnology Research Center, 22-174-4 Narita, Kitakami, Iwate 024-0003, Japan.
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Bryant MK, Schardl CL, Hesse U, Scott B. Evolution of a subtilisin-like protease gene family in the grass endophytic fungus Epichloë festucae. BMC Evol Biol 2009; 9:168. [PMID: 19615101 PMCID: PMC2717940 DOI: 10.1186/1471-2148-9-168] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 07/19/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Subtilisin-like proteases (SLPs) form a superfamily of enzymes that act to degrade protein substrates. In fungi, SLPs can play either a general nutritive role, or may play specific roles in cell metabolism, or as pathogenicity or virulence factors. RESULTS Fifteen different genes encoding SLPs were identified in the genome of the grass endophytic fungus Epichloë festucae. Phylogenetic analysis indicated that these SLPs belong to four different subtilisin families: proteinase K, kexin, pyrolysin and subtilisin. The pattern of intron loss and gain is consistent with this phylogeny. E. festucae is exceptional in that it contains two kexin-like genes. Phylogenetic analysis in Hypocreales fungi revealed an extensive history of gene loss and duplication. CONCLUSION This study provides new insights into the evolution of the SLP superfamily in filamentous fungi.
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Affiliation(s)
- Michelle K Bryant
- Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North, New Zealand.
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