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Price JL, Visagie CM, Meyer H, Yilmaz N. Fungal Species and Mycotoxins Associated with Maize Ear Rots Collected from the Eastern Cape in South Africa. Toxins (Basel) 2024; 16:95. [PMID: 38393173 PMCID: PMC10891880 DOI: 10.3390/toxins16020095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/29/2024] [Accepted: 02/04/2024] [Indexed: 02/25/2024] Open
Abstract
Maize production in South Africa is concentrated in its central provinces. The Eastern Cape contributes less than 1% of total production, but is steadily increasing its production and has been identified as a priority region for future growth. In this study, we surveyed ear rots at maize farms in the Eastern Cape, and mycotoxins were determined to be present in collected samples. Fungal isolations were made from mouldy ears and species identified using morphology and DNA sequences. Cladosporium, Diplodia, Fusarium and Gibberella ear rots were observed during field work, and of these, we collected 78 samples and isolated 83 fungal strains. Fusarium was identified from Fusarium ear rot (FER) and Gibberella ear rot (GER) and Stenocarpella from Diplodia ear rot (DER) samples, respectively. Using LC-MS/MS multi-mycotoxin analysis, it was revealed that 83% of the collected samples contained mycotoxins, and 17% contained no mycotoxins. Fifty percent of samples contained multiple mycotoxins (deoxynivalenol, 15-acetyl-deoxynivalenol, diplodiatoxin and zearalenone) and 33% contained a single mycotoxin. Fusarium verticillioides was not isolated and fumonisins not detected during this survey. This study revealed that ear rots in the Eastern Cape are caused by a wide range of species that may produce various mycotoxins.
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Affiliation(s)
- Jenna-Lee Price
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0028, South Africa; (J.-L.P.); (C.M.V.)
| | - Cobus Meyer Visagie
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0028, South Africa; (J.-L.P.); (C.M.V.)
| | - Hannalien Meyer
- Southern African Grain Laboratory (SAGL), Grain Building-Agri Hub Office Park, 477 Witherite Street, The Willows, Pretoria 0040, South Africa;
| | - Neriman Yilmaz
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0028, South Africa; (J.-L.P.); (C.M.V.)
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Zhao Q, Fan L, Deng C, Ma C, Zhang C, Zhao L. Bioconversion of chitin into chitin oligosaccharides using a novel chitinase with high chitin-binding capacity. Int J Biol Macromol 2023:125241. [PMID: 37301336 DOI: 10.1016/j.ijbiomac.2023.125241] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 05/04/2023] [Accepted: 06/05/2023] [Indexed: 06/12/2023]
Abstract
Chitin is the second largest renewable biomass resource in nature, it can be enzymatically degraded into high-value chitin oligosaccharides (CHOSs) by chitinases. In this study, a chitinase (ChiC8-1) was purified and biochemically characterized, its structure was analyzed by molecular modeling. ChiC8-1 had a molecular mass of approximately 96 kDa, exhibited its optimal activity at pH 6.0 and 50 °C. The Km and Vmax values of ChiC8-1 towards colloidal chitin were 10.17 mg mL-1 and 13.32 U/mg, respectively. Notably, ChiC8-1 showed high chitin-binding capacity, which may be related to the two chitin binding domains in the N-terminal. Based on the unique properties of ChiC8-1, a modified affinity chromatography method, which combines protein purification with chitin hydrolysis process, was developed to purify ChiC8-1 while hydrolyzing chitin. In this way, 9.36 ± 0.18 g CHOSs powder was directly obtained by hydrolyzing 10 g colloidal chitin with crude enzyme solution. The CHOSs were composed of 14.77-2.83 % GlcNAc and 85.23-97.17 % (GlcNAc)2 at different enzyme-substrate ratio. This process simplifies the tedious purification and separation steps, and may enable its potential application in the field of green production of chitin oligosaccharides.
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Affiliation(s)
- Qiong Zhao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology (SCICBT), Shanghai 200237, China
| | - Liqiang Fan
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology (SCICBT), Shanghai 200237, China
| | - Chen Deng
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology (SCICBT), Shanghai 200237, China
| | - Chunyu Ma
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology (SCICBT), Shanghai 200237, China
| | - Chunyue Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology (SCICBT), Shanghai 200237, China.
| | - Liming Zhao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology (SCICBT), Shanghai 200237, China; Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China.
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Ramazan S, Nazir I, Yousuf W, John R. Environmental stress tolerance in maize ( Zea mays): role of polyamine metabolism. FUNCTIONAL PLANT BIOLOGY : FPB 2023; 50:85-96. [PMID: 35300784 DOI: 10.1071/fp21324] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/24/2022] [Indexed: 05/21/2023]
Abstract
Maize (Zea mays L.), a major multipurpose crop for food, feed and energy is extremely susceptible to environmental perturbations and setting off the major factors for limiting maize yield. Generally, plant yields are reduced and significantly lost to adverse environments and biotic strains. To ensure the safety of living cells under unfavourable circumstances, polyamines (PAs) play an important role in regulating the response under both abiotic and biotic stresses. It is the relative abundance of higher PAs (spermidine, Spd; spermine, Spm) vis-à-vis the diamine putrescine (Put) and PA catabolism that determines the stress tolerance in plants. Climate changes and increasing demands for production of maize have made it pressing to improve the stress tolerance strategies in this plant and it is imperative to understand the role of PAs in response to various environmental perturbations. Here, we critically review and summarise the recent literature on role of PAs in conferring stress tolerance in the golden crop. The responses in terms of PA accumulation, their mechanism of action and all the recent genetic manipulation studies carried out in PA metabolism pathway, ameliorating range of abiotic and biotic stresses have been discussed. As PA metabolism under stress conditions does not operate singly within cells and is always linked to other metabolic pathways in maize, its complex connections and role as a signalling molecule have also been discussed in this review.
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Affiliation(s)
- Salika Ramazan
- Plant Molecular Biology Lab, Department of Botany, University of Kashmir, Srinagar, Jammu and Kashmir 190006, India
| | - Ifra Nazir
- Plant Molecular Biology Lab, Department of Botany, University of Kashmir, Srinagar, Jammu and Kashmir 190006, India
| | - Waseem Yousuf
- Plant Molecular Biology Lab, Department of Botany, University of Kashmir, Srinagar, Jammu and Kashmir 190006, India
| | - Riffat John
- Plant Molecular Biology Lab, Department of Botany, University of Kashmir, Srinagar, Jammu and Kashmir 190006, India
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The mitochondrial genome of the grape powdery mildew pathogen Erysiphe necator is intron rich and exhibits a distinct gene organization. Sci Rep 2021; 11:13924. [PMID: 34230575 PMCID: PMC8260586 DOI: 10.1038/s41598-021-93481-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 06/25/2021] [Indexed: 02/06/2023] Open
Abstract
Powdery mildews are notorious fungal plant pathogens but only limited information exists on their genomes. Here we present the mitochondrial genome of the grape powdery mildew fungus Erysiphe necator and a high-quality mitochondrial gene annotation generated through cloning and Sanger sequencing of full-length cDNA clones. The E. necator mitochondrial genome consists of a circular DNA sequence of 188,577 bp that harbors a core set of 14 protein-coding genes that are typically present in fungal mitochondrial genomes, along with genes encoding the small and large ribosomal subunits, a ribosomal protein S3, and 25 mitochondrial-encoded transfer RNAs (mt-tRNAs). Interestingly, it also exhibits a distinct gene organization with atypical bicistronic-like expression of the nad4L/nad5 and atp6/nad3 gene pairs, and contains a large number of 70 introns, making it one of the richest in introns mitochondrial genomes among fungi. Sixty-four intronic ORFs were also found, most of which encoded homing endonucleases of the LAGLIDADG or GIY-YIG families. Further comparative analysis of five E. necator isolates revealed 203 polymorphic sites, but only five were located within exons of the core mitochondrial genes. These results provide insights into the organization of mitochondrial genomes of powdery mildews and represent valuable resources for population genetic and evolutionary studies.
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Perlatti B, Nichols CB, Lan N, Wiemann P, Harvey CJB, Alspaugh JA, Bills GF. Identification of the Antifungal Metabolite Chaetoglobosin P From Discosia rubi Using a Cryptococcus neoformans Inhibition Assay: Insights Into Mode of Action and Biosynthesis. Front Microbiol 2020; 11:1766. [PMID: 32849391 PMCID: PMC7399079 DOI: 10.3389/fmicb.2020.01766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/06/2020] [Indexed: 01/11/2023] Open
Abstract
Cryptococcus neoformans is an important human pathogen with limited options for treatments. We have interrogated extracts from fungal fermentations to find Cryptococcus-inhibiting natural products using assays for growth inhibition, differential thermosensitivity, and synergy with existing antifungal drugs. Extracts from fermentations of strains of Discosia rubi from eastern Texas showed anticryptococcal bioactivity with preferential activity in agar zone of inhibition assays against C. neoformans at 37°C versus 25°C. Assay-guided fractionation led to the purification and identification of chaetoglobosin P as the active component of these extracts. Genome sequencing of these strains revealed a biosynthetic gene cluster consistent with chaetoglobosin biosynthesis and β-methylation of the tryptophan residue. Proximity of genes of the actin-binding protein twinfilin-1 to the chaetoglobosin P and K gene clusters suggested a possible self-resistance mechanism involving twinfilin-1 which is consistent with the predicted mechanism of action involving interference with the polymerization of the capping process of filamentous actin. A C. neoformans mutant lacking twinfilin-1 was hypersensitive to chaetoglobosin P. Chaetoglobosins also potentiated the effects of amphotericin B and caspofungin on C. neoformans.
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Affiliation(s)
- Bruno Perlatti
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, Untied States
| | - Connie B Nichols
- Departments of Medicine and Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States
| | - Nan Lan
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, Untied States
| | | | | | - J Andrew Alspaugh
- Departments of Medicine and Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States
| | - Gerald F Bills
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, Untied States
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Naumann TA, Naldrett MJ, Price NPJ. Kilbournase, a protease-associated domain subtilase secreted by the fungal corn pathogen Stenocarpella maydis. Fungal Genet Biol 2020; 141:103399. [PMID: 32387407 DOI: 10.1016/j.fgb.2020.103399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 04/23/2020] [Accepted: 04/30/2020] [Indexed: 10/24/2022]
Abstract
Subtilases are a large family of serine proteases that occur throughout biology. A small subset contain protease-associated (PA) domains that are structurally separate from but encoded within the active site. In bacteria, subtilase PA domains function to recruit specific protein substrates. Here we demonstrate that a protease secreted by the fungal corn pathogen Stenocarpella maydis, which truncates corn ChitA chitinase, is a PA domain subtilase. Protease was purified from S. maydis cultures and tryptic peptides were analyzed by LC-MS/MS. Ions were mapped to two predicted PA domain subtilases. Yeast strains were engineered to express each protease. One failed to produce recombinant protein while the other secreted protease that truncated ChitA. This protease, that we named kilbournase, was purified and characterized. It cleaved multiple peptide bonds in the amino-terminal chitin binding domain of ChitA while leaving the catalytic domain intact. Kilbournase was more active on the ChitA-B73 alloform compared to ChitA-LH82 and did not cleave AtChitIV3, a homolog from Arabidopsis thaliana, indicating a high level of specificity. Truncation of corn ChitA by kilbournase resembles truncation of human C5a by Streptococcus pyogenes ScpA, arguing that PA domain proteases in bacteria and fungi may commonly target specific host proteins.
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Affiliation(s)
- Todd A Naumann
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agriculture Utilization Research, Peoria, IL 61604, United States.
| | - Michael J Naldrett
- Nebraska Center for Biotechnology, Beadle Center, University of Nebraska-Lincoln, Lincoln, NE 68588, United States
| | - Neil P J Price
- Renewable Product Technology Research Unit, National Center for Agriculture Utilization Research, Peoria, IL 61604, United States
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