Research

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15 pages, 6545 KiB

Open AccessArticle

Hyphopodium-Specific Signaling Is Required for Plant Infection by Verticillium dahliae

by Qingyan Liu, Yingchao Li, Huawei Wu, Bosen Zhang, Chuanhui Liu, Yi Gao, Huishan Guo and Jianhua Zhao

J. Fungi 2023, 9(4), 484; https://doi.org/10.3390/jof9040484 - 18 Apr 2023

Viewed by 1406

Abstract

For successful colonization, fungal pathogens have evolved specialized infection structures to overcome the barriers present in host plants. The morphology of infection structures and pathogenic mechanisms are diverse according to host specificity. Verticillium dahliae, a soil-borne phytopathogenic fungus, generates hyphopodium with a [...] Read more.

For successful colonization, fungal pathogens have evolved specialized infection structures to overcome the barriers present in host plants. The morphology of infection structures and pathogenic mechanisms are diverse according to host specificity. Verticillium dahliae, a soil-borne phytopathogenic fungus, generates hyphopodium with a penetration peg on cotton roots while developing appressoria, that are typically associated with leaf infection on lettuce and fiber flax roots. In this study, we isolated the pathogenic fungus, V. dahliae (Vda^Sm), from Verticillium wilt eggplants and generated a GFP-labeled isolate to explore the colonization process of Vda^Sm on eggplants. We found that the formation of hyphopodium with penetration peg is crucial for the initial colonization of Vda^Sm on eggplant roots, indicating that the colonization processes on eggplant and cotton share a similar feature. Furthermore, we demonstrated that the VdNoxB/VdPls1-dependent Ca²⁺ elevation activating VdCrz1 signaling is a common genetic pathway to regulate infection-related development in V. dahliae. Our results indicated that VdNoxB/VdPls1-dependent pathway may be a desirable target to develop effective fungicides, to protect crops from V. dahliae infection by interrupting the formation of specialized infection structures. Full article

(This article belongs to the Special Issue The Role of Fungi in Plant Defense Mechanisms)

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12 pages, 2496 KiB

Open AccessArticle

Uncovering the Role of PdePrx12 Peroxidase in Enhancing Disease Resistance in Poplar Trees

by Guanghua Cai, Yan Zhang, Liyu Huang and Nian Wang

J. Fungi 2023, 9(4), 410; https://doi.org/10.3390/jof9040410 - 27 Mar 2023

Cited by 3 | Viewed by 1107

Abstract

Peroxidase (Prx)-related genes are reported to be involved in the metabolism of hydrogen peroxide (H₂O₂) in plants. Here, we found that the expression of the PdePrx12 gene was upregulated in wild-type (WT) poplar line NL895 infected with the pathogens [...] Read more.

Peroxidase (Prx)-related genes are reported to be involved in the metabolism of hydrogen peroxide (H₂O₂) in plants. Here, we found that the expression of the PdePrx12 gene was upregulated in wild-type (WT) poplar line NL895 infected with the pathogens Botryosphaeria dothidea strain 3C and Alternaria alternata strain 3E. The PdePrx12 gene was cloned in the poplar line NL895 and its overexpression (OE) and reduced-expression (RE) vectors were constructed. OE and RE transgenic lines were then generated. The H₂O₂ content in the leaves was measured by DAB staining and spectrophotometric analysis, and the data revealed that the OE line had a reduced H₂O₂ content, whereas the RE line had an increased H₂O₂ content. These transgenic and WT plants were also inoculated with the 3C/3E pathogens. The leaf area infected by pathogen 3C/3E was determined and the OE line was found to have a larger area of infection, whereas the RE line was found to have a smaller area of infection. This result suggested PdePRX12 is involved in disease resistance in poplar. Given these results, this study demonstrated that when poplar is infected by pathogens, the expression of PdePrx12 is inhibited, leading to an increase in H₂O₂ content, thereby enhancing disease resistance. Full article

(This article belongs to the Special Issue The Role of Fungi in Plant Defense Mechanisms)

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24 pages, 4186 KiB

Open AccessArticle

Assessing the Biocontrol Potential of Clonostachys Species Isolated as Endophytes from Coffea Species and as Mycoparasites of Hemileia Rusts of Coffee in Africa

by Miraine Kapeua-Ndacnou, Lucas Magalhães de Abreu, Davi Mesquita de Macedo, Thaisa Ferreira da Nóbrega, Caio Mattos Pereira, Harry Charles Evans and Robert Weingart Barreto

J. Fungi 2023, 9(2), 248; https://doi.org/10.3390/jof9020248 - 13 Feb 2023

Cited by 3 | Viewed by 2241

Abstract

During surveys conducted in South America and Africa to identify natural fungal enemies of coffee leaf rust (CLR), Hemileia vastatrix, over 1500 strains were isolated, either as endophytes from healthy tissues of Coffea species or as mycoparasites growing on rust pustules. Based [...] Read more.

During surveys conducted in South America and Africa to identify natural fungal enemies of coffee leaf rust (CLR), Hemileia vastatrix, over 1500 strains were isolated, either as endophytes from healthy tissues of Coffea species or as mycoparasites growing on rust pustules. Based on morphological data, eight isolates—three isolated from wild or semiwild coffee and five from Hemileia species on coffee, all from Africa—were provisionally assigned to the genus Clonostachys. A polyphasic study of their morphological, cultural and molecular characteristics—including the Tef1 (translation elongation factor 1 alpha), RPB1 (largest subunit of RNA polymerase II), TUB (β-tubulin) and ACL1 (ATP citrate lyase) regions—confirmed these isolates as belonging to three species of the genus Clonostachys: namely C. byssicola, C. rhizophaga and C. rosea f. rosea. Preliminary assays were also conducted to test the potential of the Clonostachys isolates to reduce CLR severity on coffee under greenhouse conditions. Foliar and soil applications indicated that seven of the isolates had a significant effect (p < 0.05) in reducing CLR severity. In parallel, in vitro tests that involved conidia suspensions of each of the isolates together with urediniospores of H. vastatrix resulted in high levels of inhibition of urediniospore germination. All eight isolates showed their ability to establish as endophytes in C. arabica during this study, and some proved to be mycoparasites of H. vastatrix. In addition to reporting the first records of Clonostachys associated with healthy coffee tissues and with Hemileia rusts of coffee, this work provides the first evidence that Clonostachys isolates have potential as biological control agents against CLR. Full article

(This article belongs to the Special Issue The Role of Fungi in Plant Defense Mechanisms)

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20 pages, 6248 KiB

Open AccessArticle

Antifungal Activity and Biocontrol Potential of Simplicillium lamellicola JC-1 against Multiple Fungal Pathogens of Oilseed Rape

by Wenting Li, Tao Luo, Juncheng Li, Jing Zhang, Mingde Wu, Long Yang and Guoqing Li

J. Fungi 2023, 9(1), 57; https://doi.org/10.3390/jof9010057 - 30 Dec 2022

Cited by 6 | Viewed by 1932

Abstract

A fungal strain (JC-1) of Simplicillium was isolated from a pod of oilseed rape (Brassica napus) infested with the blackleg pathogen Leptosphaeria biglobosa. This study was done to clarify its taxonomic identity using morphological and molecular approaches, to characterize its [...] Read more.

A fungal strain (JC-1) of Simplicillium was isolated from a pod of oilseed rape (Brassica napus) infested with the blackleg pathogen Leptosphaeria biglobosa. This study was done to clarify its taxonomic identity using morphological and molecular approaches, to characterize its antifungal activity through bioassays and genome-based identification of antifungal metabolites, and to determine its efficacy in inducing systemic resistance (ISR) in oilseed rape. The results showed that JC-1 belongs to Simplicillium lamellicola. It displayed a strong antagonistic relationship with L. biglobosa, Botrytis cinerea (gray mold) and Sclerotinia sclerotiorum (stem rot). The cultural filtrates of JC-1 showed a high efficacy in suppressing infection by S. sclerotiorum on detached leaves of oilseed rape. Genome analysis indicated that JC-1 has the capability of producing multiple antifungal metabolites, including aureobasidin A1, squalestatin S1 and verlamelin. Inoculation of JC-1 on seeds of oilseed rape caused a suppressive effect on infection by L. biglobosa on the cotyledons of the resulting seedlings, suggesting that JC-1 can trigger ISR. Endophytic growth, accumulation of anthocyanins, up-regulated expression of CHI (for chalcone isomerase) and PR1 (for pathogenesis-related protein 1), and down-regulated expression of NECD3 (for 9-cis-epoxycarotenoid dioxygenase) were detected to be associated with the ISR. This study provided new insights into the biocontrol potential and modes of action of S. lamellicola. Full article

(This article belongs to the Special Issue The Role of Fungi in Plant Defense Mechanisms)

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16 pages, 2900 KiB

Open AccessArticle

The Small Ras Superfamily GTPase Rho4 of the Maize Anthracnose Fungus Colletotrichum graminicola Is Required for β-1,3-glucan Synthesis, Cell Wall Integrity, and Full Virulence

by Ely Oliveira-Garcia, Lala Aliyeva-Schnorr, Alan De Oliveira Silva, Seif El Din Ghanem, Kathrin Thor, Edgar Peiter and Holger B. Deising

J. Fungi 2022, 8(10), 997; https://doi.org/10.3390/jof8100997 - 22 Sep 2022

Cited by 2 | Viewed by 1557

Abstract

Small Ras superfamily GTPases are highly conserved regulatory factors of fungal cell wall biosynthesis and morphogenesis. Previous experiments have shown that the Rho4-like protein of the maize anthracnose fungus Colletotrichum graminicola, formerly erroneously annotated as a Rho1 protein, physically interacts with the [...] Read more.

Small Ras superfamily GTPases are highly conserved regulatory factors of fungal cell wall biosynthesis and morphogenesis. Previous experiments have shown that the Rho4-like protein of the maize anthracnose fungus Colletotrichum graminicola, formerly erroneously annotated as a Rho1 protein, physically interacts with the β-1,3-glucan synthase Gls1 (Lange et al., 2014; Curr. Genet. 60:343–350). Here, we show that Rho4 is required for β-1,3-glucan synthesis. Accordingly, Δrho4 strains formed distorted vegetative hyphae with swellings, and exhibited strongly reduced rates of hyphal growth and defects in asexual sporulation. Moreover, on host cuticles, conidia of Δrho4 strains formed long hyphae with hyphopodia, rather than short germ tubes with appressoria. Hyphopodia of Δrho4 strains exhibited penetration defects and often germinated laterally, indicative of cell wall weaknesses. In planta differentiated infection hyphae of Δrho4 strains were fringy, and anthracnose disease symptoms caused by these strains on intact and wounded maize leaf segments were significantly weaker than those caused by the WT strain. A retarded disease symptom development was confirmed by qPCR analyses. Collectively, we identified the Ras GTPase Rho4 as a new virulence factor of C. graminicola. Full article

(This article belongs to the Special Issue The Role of Fungi in Plant Defense Mechanisms)

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11 pages, 3492 KiB

Open AccessArticle

Trichoderma asperelloides PSU-P1 Induced Expression of Pathogenesis-Related Protein Genes against Gummy Stem Blight of Muskmelon (Cucumis melo) in Field Evaluation

by Warin Intana, Prisana Wonglom, Nakarin Suwannarach and Anurag Sunpapao

J. Fungi 2022, 8(2), 156; https://doi.org/10.3390/jof8020156 - 04 Feb 2022

Cited by 11 | Viewed by 2010

Abstract

Gummy stem blight caused by Stagonosporopsis cucurbitacearum is the most destructive disease of muskmelon cultivation. This study aimed to induce disease resistance against gummy stem blight in muskmelon by Trichoderma asperelloides PSU-P1. This study was arranged into two crops. Spore suspension at a [...] Read more.

Gummy stem blight caused by Stagonosporopsis cucurbitacearum is the most destructive disease of muskmelon cultivation. This study aimed to induce disease resistance against gummy stem blight in muskmelon by Trichoderma asperelloides PSU-P1. This study was arranged into two crops. Spore suspension at a concentration of 1 × 10⁶ spores/mL of T. asperelloides PSU-P1 was applied to muskmelon to investigate gene expression. The expression of PR genes including chitinase (chi) and β-1,3-glucanase (glu) were determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR), and enzyme activity was assayed by the DNS method. The effects of T. asperelloides PSU-P1 on growth, yield, and postharvest quality of muskmelon fruit were measured. A spore suspension at a concentration of 1 × 10⁶ spore/mL of T. asperelloides PSU-P1 and S. cucurbitacearum was applied to muskmelons to determine the reduction in disease severity. The results showed that the expression of chi and glu genes in T. asperelloides PSU-P1-treated muskmelon plants was 7–10-fold higher than that of the control. The enzyme activities of chitinase and β-1,3-glucanase were 0.15–0.284 and 0.343–0.681 U/mL, respectively, which were higher than those of the control (pathogen alone). Scanning electron microscopy revealed crude metabolites extracted from T. asperelloides PSU-P1-treated muskmelon plants caused wilting and lysis of S. cucurbitacearum hyphae, confirming the activity of cell-wall-degrading enzymes (CWDEs). Application of T. asperelloides PSU-P1 increased fruit weight and fruit width; sweetness and fruit texture were not significantly different among treated muskmelons. Application of T. asperelloides PSU-P1 reduced the disease severity scale of gummy stem blight to 1.10 in both crops, which was significantly lower than that of the control (2.90 and 3.40, respectively). These results revealed that application of T. asperelloides PSU-P1 reduced disease severity against gummy stem blight by overexpressed PR genes and elevated enzyme activity in muskmelon plants. Full article

(This article belongs to the Special Issue The Role of Fungi in Plant Defense Mechanisms)

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Review

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15 pages, 1919 KiB

Open AccessReview

Ascochyta Blight in Chickpea: An Update

by Emiliano Foresto, María Evangelina Carezzano, Walter Giordano and Pablo Bogino

J. Fungi 2023, 9(2), 203; https://doi.org/10.3390/jof9020203 - 04 Feb 2023

Cited by 5 | Viewed by 2525

Abstract

Chickpea (Cicer arietinum L.), one of the most cultivated legumes worldwide, is crucial for the economy of several countries and a valuable source of nutrients. Yields may be severely affected by Ascochyta blight, a disease caused by the fungus Ascochyta rabiei. [...] Read more.

Chickpea (Cicer arietinum L.), one of the most cultivated legumes worldwide, is crucial for the economy of several countries and a valuable source of nutrients. Yields may be severely affected by Ascochyta blight, a disease caused by the fungus Ascochyta rabiei. Molecular and pathological studies have not yet managed to establish its pathogenesis, since it is highly variable. Similarly, much remains to be elucidated about plant defense mechanisms against the pathogen. Further knowledge of these two aspects is fundamental for the development of tools and strategies to protect the crop. This review summarizes up-to-date information on the disease’s pathogenesis, symptomatology, and geographical distribution, as well as on the environmental factors that favor infection, host defense mechanisms, and resistant chickpea genotypes. It also outlines existing practices for integrated blight management. Full article

(This article belongs to the Special Issue The Role of Fungi in Plant Defense Mechanisms)

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18 pages, 2252 KiB

Open AccessReview

Lignin and Its Pathway-Associated Phytoalexins Modulate Plant Defense against Fungi

by Vincent Ninkuu, Jianpei Yan, Zenchao Fu, Tengfeng Yang, James Ziemah, Matthias S. Ullrich, Nikolai Kuhnert and Hongmei Zeng

J. Fungi 2023, 9(1), 52; https://doi.org/10.3390/jof9010052 - 29 Dec 2022

Cited by 23 | Viewed by 3685

Abstract

Fungi infections cause approximately 60–70% yield loss through diseases such as rice blast, powdery mildew, Fusarium rot, downy mildew, etc. Plants naturally respond to these infections by eliciting an array of protective metabolites to confer physical or chemical protection. Among plant metabolites, lignin, [...] Read more.

Fungi infections cause approximately 60–70% yield loss through diseases such as rice blast, powdery mildew, Fusarium rot, downy mildew, etc. Plants naturally respond to these infections by eliciting an array of protective metabolites to confer physical or chemical protection. Among plant metabolites, lignin, a phenolic compound, thickens the middle lamella and the secondary cell walls of plants to curtail fungi infection. The biosynthesis of monolignols (lignin monomers) is regulated by genes whose transcript abundance significantly improves plant defense against fungi. The catalytic activities of lignin biosynthetic enzymes also contribute to the accumulation of other defense compounds. Recent advances focus on modifying the lignin pathway to enhance plant growth and defense against pathogens. This review presents an overview of monolignol regulatory genes and their contributions to fungi immunity, as reported over the last five years. This review expands the frontiers in lignin pathway engineering to enhance plant defense. Full article

(This article belongs to the Special Issue The Role of Fungi in Plant Defense Mechanisms)

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10 pages, 1176 KiB

Open AccessReview

Metagenomics Next Generation Sequencing (mNGS): An Exciting Tool for Early and Accurate Diagnostic of Fungal Pathogens in Plants

by Fatma Şeyma Gökdemir, Özlem Darcansoy İşeri, Abhishek Sharma, Premila N. Achar and Füsun Eyidoğan

J. Fungi 2022, 8(11), 1195; https://doi.org/10.3390/jof8111195 - 13 Nov 2022

Cited by 9 | Viewed by 4133

Abstract

Crop output is directly impacted by infections, with fungi as the major plant pathogens, making accurate diagnosis of these threats crucial. Developing technology and multidisciplinary approaches are turning to genomic analyses in addition to traditional culture methods in diagnostics of fungal plant pathogens. [...] Read more.

Crop output is directly impacted by infections, with fungi as the major plant pathogens, making accurate diagnosis of these threats crucial. Developing technology and multidisciplinary approaches are turning to genomic analyses in addition to traditional culture methods in diagnostics of fungal plant pathogens. The metagenomic next-generation sequencing (mNGS) method is preferred for genotyping identification of organisms, identification at the species level, illumination of metabolic pathways, and determination of microbiota. Moreover, the data obtained so far show that this new approach is promising as an emerging new trend in fungal disease detection. Another approach covered by mNGS technologies, known as metabarcoding, enables use of specific markers specific to a genetic region and allows for genotypic identification by facilitating the sequencing of certain regions. Although the core concept of mNGS remains constant across applications, the specific sequencing methods and bioinformatics tools used to analyze the data differ. In this review, we focus on how mNGS technology, including metabarcoding, is applied for detecting fungal pathogens and its promising developments for the future. Full article

(This article belongs to the Special Issue The Role of Fungi in Plant Defense Mechanisms)

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18 pages, 2473 KiB

Open AccessReview

Plant-Derived Protectants in Combating Soil-Borne Fungal Infections in Tomato and Chilli

by Himanshu Arora, Abhishek Sharma, Peter Poczai, Satyawati Sharma, Farah Farhanah Haron, Abdul Gafur and R. Z. Sayyed

J. Fungi 2022, 8(2), 213; https://doi.org/10.3390/jof8020213 - 21 Feb 2022

Cited by 12 | Viewed by 3465

Abstract

Fungal infections transmitted through the soil continue to pose a threat to a variety of horticultural and agricultural products, including tomato and chilli. The indiscriminate use of synthetic pesticides has resulted in a slew of unintended consequences for the surrounding ecosystem. To achieve [...] Read more.

Fungal infections transmitted through the soil continue to pose a threat to a variety of horticultural and agricultural products, including tomato and chilli. The indiscriminate use of synthetic pesticides has resulted in a slew of unintended consequences for the surrounding ecosystem. To achieve sustainable productivity, experts have turned their attention to natural alternatives. Due to their biodegradability, varied mode of action, and minimal toxicity to non-target organisms, plant-derived protectants (PDPs) are being hailed as a superior replacement for plant pesticides. This review outlines PDPs’ critical functions (including formulations) in regulating soil-borne fungal diseases, keeping tomato and chilli pathogens in the spotlight. An in-depth examination of the impact of PDPs on pathogen activity will be a priority. Additionally, this review emphasises the advantages of the in silico approach over conventional approaches for screening plants’ secondary metabolites with target-specific fungicidal activity. Despite the recent advances in our understanding of the fungicidal capabilities of various PDPs, it is taking much longer for that information to be applied to commercially available pesticides. The restrictions to solving this issue can be lifted by breakthroughs in formulation technology, governmental support, and a willingness to pursue green alternatives among farmers and industries. Full article

(This article belongs to the Special Issue The Role of Fungi in Plant Defense Mechanisms)

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