Pathogens

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17 pages, 1962 KiB

Open AccessArticle

Chromosome-Level Assemblies for the Pine Pitch Canker Pathogen Fusarium circinatum

by Lieschen De Vos, Magriet A. van der Nest, Quentin C. Santana, Stephanie van Wyk, Kyle S. Leeuwendaal, Brenda D. Wingfield and Emma T. Steenkamp

Pathogens 2024, 13(1), 70; https://doi.org/10.3390/pathogens13010070 - 12 Jan 2024

Cited by 1 | Viewed by 1676

Abstract

The pine pitch canker pathogen, Fusarium circinatum, is globally regarded as one of the most important threats to commercial pine-based forestry. Although genome sequences of this fungus are available, these remain highly fragmented or structurally ill-defined. Our overall goal was to provide [...] Read more.

The pine pitch canker pathogen, Fusarium circinatum, is globally regarded as one of the most important threats to commercial pine-based forestry. Although genome sequences of this fungus are available, these remain highly fragmented or structurally ill-defined. Our overall goal was to provide high-quality assemblies for two notable strains of F. circinatum, and to characterize these in terms of coding content, repetitiveness and the position of telomeres and centromeres. For this purpose, we used Oxford Nanopore Technologies MinION long-read sequences, as well as Illumina short sequence reads. By leveraging the genomic synteny inherent to F. circinatum and its close relatives, these sequence reads were assembled to chromosome level, where contiguous sequences mostly spanned from telomere to telomere. Comparative analyses unveiled remarkable variability in the twelfth and smallest chromosome, which is known to be dispensable. It presented a striking length polymorphism, with one strain lacking substantial portions from the chromosome’s distal and proximal regions. These regions, characterized by a lower gene density, G+C content and an increased prevalence of repetitive elements, contrast starkly with the syntenic segments of the chromosome, as well as with the core chromosomes. We propose that these unusual regions might have arisen or expanded due to the presence of transposable elements. A comparison of the overall chromosome structure revealed that centromeric elements often underpin intrachromosomal differences between F. circinatum strains, especially at chromosomal breakpoints. This suggests a potential role for centromeres in shaping the chromosomal architecture of F. circinatum and its relatives. The publicly available genome data generated here, together with the detailed metadata provided, represent essential resources for future studies of this important plant pathogen. Full article

(This article belongs to the Special Issue Plant Pathogenic Fungi)

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16 pages, 4296 KiB

Open AccessArticle

Characterization of Pseudofusicoccum Species from Diseased Plantation-Grown Acacia mangium, Eucalyptus spp., and Pinus massoniana in Southern China

by Guoqing Li, Wenxia Wu, Linqin Lu, Bingyin Chen and Shuaifei Chen

Pathogens 2023, 12(4), 574; https://doi.org/10.3390/pathogens12040574 - 8 Apr 2023

Cited by 1 | Viewed by 2028

Abstract

Fungi from Pseudofusicoccum (Phyllostictaceae, Botryosphaeriales) have been reported as pathogens, endophytes, or saprophytes from various woody plants in different countries. Recently, Botryosphaeriales isolates were obtained from the dead twigs of Acacia mangium, Eucalyptus spp., Pinus massoniana, and Cunninghamia lanceolata in Guangdong, [...] Read more.

Fungi from Pseudofusicoccum (Phyllostictaceae, Botryosphaeriales) have been reported as pathogens, endophytes, or saprophytes from various woody plants in different countries. Recently, Botryosphaeriales isolates were obtained from the dead twigs of Acacia mangium, Eucalyptus spp., Pinus massoniana, and Cunninghamia lanceolata in Guangdong, Guangxi, Hainan, and Fujian Provinces in southern China. This study aimed to understand the diversity, distribution, and virulence of these Pseudofusicoccum species on these trees. A total of 126 Pseudofusicoccum isolates were obtained, and the incidences of Pseudofusicoccum (percentage of trees that yielded Pseudofusicoccum) on A. mangium, P. massoniana, Eucalyptus spp., and C. lanceolata were 21%, 2.6%, 0.5%, and 0%, respectively. Based on the internal transcribed spacer (ITS), translation elongation factor 1-alpha (tef1), and β-tubulin (tub2) loci, 75% of the total isolates were identified as P. kimberleyense, and the remaining isolates were identified as P. violaceum. For P. kimberleyense, the majority of isolates (83%) were from A. mangium, and the rest were from P. massoniana (14%) and Eucalyptus spp. (3%). Similarly, the proportion of isolates of P. violaceum from A. mangium, P. massoniana, and Eucalyptus spp. were 84%, 13%, and 3%, respectively. Inoculation trials showed that the two species produced expected lesions on the tested seedlings of A. mangium, E. urophylla × E. grandis, and P. elliottii. This study provides fundamental information on Pseudofusicoccum associated with diseases in main plantations in southern China. Full article

(This article belongs to the Special Issue Plant Pathogenic Fungi)

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14 pages, 3667 KiB

Open AccessArticle

mRNA Turnover Protein 4 Is Vital for Fungal Pathogenicity and Response to Oxidative Stress in Sclerotinia sclerotiorum

by Chenghuizi Yang, Lan Tang, Lei Qin, Weiping Zhong, Xianyu Tang, Xin Gong, Wenqi Xie, Yifu Li and Shitou Xia

Pathogens 2023, 12(2), 281; https://doi.org/10.3390/pathogens12020281 - 8 Feb 2023

Cited by 3 | Viewed by 2041

Abstract

Ribosome assembly factors have been extensively studied in yeast, and their abnormalities may affect the assembly process of ribosomes and cause severe damage to cells. However, it is not clear whether mRNA turnover protein 4 (MRT4) functions in the fungal growth and pathogenicity [...] Read more.

Ribosome assembly factors have been extensively studied in yeast, and their abnormalities may affect the assembly process of ribosomes and cause severe damage to cells. However, it is not clear whether mRNA turnover protein 4 (MRT4) functions in the fungal growth and pathogenicity in Sclerotinia sclerotiorum. Here, we identified the nucleus-located gene SsMRT4 using reverse genetics, and found that knockdown of SsMRT4 resulted in retard mycelia growth and complete loss of pathogenicity. Furthermore, mrt4 knockdown mutants showed almost no appressorium formation and oxalic acid production comparing to the wild-type and complementary strains. In addition, the abilities to ROS elimination and resistance to oxidative and osmotic stresses were also seriously compromised in mrt4 mutants. Overall, our study clarified the role of SsMRT4 in S. sclerotiorum, providing new insights into ribosome assembly in regulating pathogenicity and resistance to environmental stresses of fungi. Full article

(This article belongs to the Special Issue Plant Pathogenic Fungi)

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9 pages, 2986 KiB

Open AccessArticle

Evaluating the Utility of Simplicillium lanosoniveum, a Hyperparasitic Fungus of Puccinia graminis f. sp. tritici, as a Biological Control Agent against Wheat Stem Rust

by Binbin Si, Hui Wang, Jiaming Bai, Yuzhen Zhang and Yuanyin Cao

Pathogens 2023, 12(1), 22; https://doi.org/10.3390/pathogens12010022 - 23 Dec 2022

Cited by 3 | Viewed by 2127

Abstract

Wheat stem rust is one of the wheat diseases caused by Puccinia graminis Pers. f. sp. tritici (Pgt). This disease has been responsible for major losses to wheat production worldwide. Currently used methods for controlling this disease include fungicides, the breeding of [...] Read more.

Wheat stem rust is one of the wheat diseases caused by Puccinia graminis Pers. f. sp. tritici (Pgt). This disease has been responsible for major losses to wheat production worldwide. Currently used methods for controlling this disease include fungicides, the breeding of stem rust-resistant cultivars, and preventive agricultural measures. However, the excessive use of fungicides can have various deleterious effects on the environment. A hyperparasitic fungus with white mycelia and oval conidia, Simplicillium lanosoniveum, was isolated from the urediniospores of Pgt. When Pgt-infected wheat leaves were inoculation with isolates of S. lanosoniveum, it was found that S. lanosoniveum inoculation inhibited the production and germination of urediniospores, suggesting that S. lanosoniveum could inhibit the growth and spread of Pgt. Scanning electron microscopy revealed that S. lanosoniveum could inactivate the urediniospores by inducing structural damage. Overall, findings indicate that S. lanosoniveum might provide an effective biological agent for the control of Pgt. Full article

(This article belongs to the Special Issue Plant Pathogenic Fungi)

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9 pages, 2146 KiB

Open AccessArticle

Identification of the Pathogen Causing Leaf Spot in Zinnia elegans and Its Sensitivity to Five Fungicides

by Yu Liu, Qiuyu Yao, Shuang Liang, Cheng Li, Xiangsheng Chen and Zhong Li

Pathogens 2022, 11(12), 1454; https://doi.org/10.3390/pathogens11121454 - 1 Dec 2022

Viewed by 2604

Abstract

Zinnia elegans Jacq. is an important, globally cultivated ornamental plant. In August 2021, a leaf spot disease was observed in zinnia in Shibing County, Guizhou, China, with an incidence of approximately 60%. Pathogens were isolated and purified from the infected leaves by tissue [...] Read more.

Zinnia elegans Jacq. is an important, globally cultivated ornamental plant. In August 2021, a leaf spot disease was observed in zinnia in Shibing County, Guizhou, China, with an incidence of approximately 60%. Pathogens were isolated and purified from the infected leaves by tissue isolation, and pathogen strain BRJ2 was confirmed as the pathogen causing the leaf spot. Based on morphology and ITS, TEF-1α, and TUB2 sequence analyses, the pathogen was identified as Nigrospora musae (McLennan and Hoëtte). The mycelial growth rate method was used to determine the in vitro toxicity of five fungicides to the pathogen. The results showed that 10% difenoconazole provided the strongest inhibitory effect on N. musae, with a concentration for 50% of maximal effect (EC₅₀) of 0.0658 mg/L; 75% trifloxystrobin·tebuconazole had the second greatest effect, with an EC₅₀ of 0.1802 mg/L. This study provides the first report that N. musae caused leaf spot disease in Z. elegans and provides important guidance for the effective prevention and control of this disease in Guizhou. Full article

(This article belongs to the Special Issue Plant Pathogenic Fungi)

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12 pages, 2309 KiB

Open AccessArticle

First Record of Colletotrichum anthrisci Causing Anthracnose on Avocado Fruits in Chile

by Marcelo I. Bustamante, Claudio Osorio-Navarro, Ysadora Fernández, Tyler B. Bourret, Alan Zamorano and José Luis Henríquez-Sáez

Pathogens 2022, 11(10), 1204; https://doi.org/10.3390/pathogens11101204 - 19 Oct 2022

Cited by 7 | Viewed by 3843

Abstract

Anthracnose caused by Colletotrichum species is one of the most frequent and damaging fungal diseases affecting avocado fruits (Persea americana Mill.) worldwide. In Chile, the disease incidence has increased over the last decades due to the establishment of commercial groves in more [...] Read more.

Anthracnose caused by Colletotrichum species is one of the most frequent and damaging fungal diseases affecting avocado fruits (Persea americana Mill.) worldwide. In Chile, the disease incidence has increased over the last decades due to the establishment of commercial groves in more humid areas. Since 2018, unusual symptoms of anthracnose have been observed on Hass avocado fruits, with lesions developing a white to gray sporulation. Morphological features and multi-locus phylogenetic analyses using six DNA barcodes (act, chs-1, gapdh, his3, ITS, and tub2) allowed the identification of the causal agent as Colletotrichum anthrisci, a member of the dematium species complex. Pathogenicity was confirmed by inoculating healthy Hass avocado fruits with representative isolates, reproducing the same symptoms initially observed, and successfully reisolating the same isolates from the margin of the necrotic pulp. Previously, several Colletotrichum species belonging to other species complexes have been associated with avocado anthracnose in other countries. To our knowledge, this is the first record of C. anthrisci and of a species of the dematium species complex causing anthracnose on avocado fruits in Chile and worldwide. Full article

(This article belongs to the Special Issue Plant Pathogenic Fungi)

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15 pages, 1245 KiB

Open AccessArticle

Genetic Diversity of Venturia inaequalis in Latvia Revealed by Microsatellite Markers

by Olga Sokolova, Inga Moročko-Bičevska and Gunārs Lācis

Pathogens 2022, 11(10), 1165; https://doi.org/10.3390/pathogens11101165 - 9 Oct 2022

Cited by 3 | Viewed by 1815

Abstract

Apple scab caused by the ascomycete Venturia inaequalis is an economically significant disease worldwide. The annual sexual reproduction of V. inaequalis leads to high variation, changes in the population’s genetic structure and adaptations to the changing environment, including overcoming the host’s resistance. The [...] Read more.

Apple scab caused by the ascomycete Venturia inaequalis is an economically significant disease worldwide. The annual sexual reproduction of V. inaequalis leads to high variation, changes in the population’s genetic structure and adaptations to the changing environment, including overcoming the host’s resistance. The objective of this study is to characterise and assess the genetic diversity of V. inaequalis populations in two main apple-growing regions in Latvia. In total, 143 V. inaequalis isolates were collected from Latvia, six reference strains with known virulence were obtained from other countries, and all strains were genotyped by 12 SSR markers. The SSR markers were highly variable and informative, identifying 158 alleles that ranged from two to 29 per locus. The Bayesian clustering identified three genetic lineages among the Latvian isolates that did not correlate to the geographic origin, host genotype, organ (leaves or fruits) from which the pathogen was isolated, time of collection, and type of isolation (single conidium or ascospore). The possible relatedness to virulence was detected when reference strains with known virulence were included in the analysis. Our findings correspond with previous studies demonstrating that V. inaequalis in Europe has a high genetic diversity within populations, but low diversity among the populations. Full article

(This article belongs to the Special Issue Plant Pathogenic Fungi)

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10 pages, 1925 KiB

Open AccessArticle

First Record of Alternaria pogostemonis: A Novel Species Causing Leaf Spots in Pogostemon cablin

by Mei Luo, Minping Zhao, Yinghua Huang, Jiawei Liu, Qiurong Huang, Yongxin Shu and Zhangyong Dong

Pathogens 2022, 11(10), 1105; https://doi.org/10.3390/pathogens11101105 - 27 Sep 2022

Cited by 3 | Viewed by 2000

Abstract

Pogostemon cablin (Lamiaceae) is a component of traditional medicines in Southern China. The identification of P. cablin pathogens is essential for the production and development of this industry. During 2019–2020, a leaf spot on P. cablin was observed in Zhanjiang, Guangdong [...] Read more.

Pogostemon cablin (Lamiaceae) is a component of traditional medicines in Southern China. The identification of P. cablin pathogens is essential for the production and development of this industry. During 2019–2020, a leaf spot on P. cablin was observed in Zhanjiang, Guangdong Province. The pathogen of the leaf spot was isolated and identified using morphological and phylogenetic methods. Phylogenetic analysis was performed using the internal transcribed spacer (ITS) region, glyceraldehyde-3-phosphate dehydrogenase (gapdh), RNA polymerase II (rpb2), translation extension factor 1-alpha (tef1), and Alternaria major allergen 1 (Alt-a1) genes. Based on phylogenetic and morphological studies, this was confirmed to be a novel species of Alternaria pogostemonis, with description and illustrations presented. The pathogenicity test of A. pogostemon was verified by Koch’s postulates as causing leaf spot disease. This is the first report of leaf spot disease in P. cablin caused by the Alternaria species. This study contributes to the knowledge of P. cablin leaf spot diseases. Full article

(This article belongs to the Special Issue Plant Pathogenic Fungi)

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14 pages, 1792 KiB

Open AccessArticle

Fungal Endophytes Isolated from Elymus repens, a Wild Relative of Barley, Have Potential for Biological Control of Fusarium culmorum and Pyrenophora teres in Barley

by Anna Kaja Høyer, Hans Jørgen Lyngs Jørgensen, Trevor Roland Hodkinson and Birgit Jensen

Pathogens 2022, 11(10), 1097; https://doi.org/10.3390/pathogens11101097 - 25 Sep 2022

Cited by 3 | Viewed by 2028

Abstract

Twenty-four fungal endophytes, isolated from a wild relative of barley, Elymus repens, were screened in barley against an isolate of Fusarium culmorum and an isolate of Pyrenophora teres under controlled conditions. In all experiments, the endophytes were applied individually as seed dressings. Five [...] Read more.

Twenty-four fungal endophytes, isolated from a wild relative of barley, Elymus repens, were screened in barley against an isolate of Fusarium culmorum and an isolate of Pyrenophora teres under controlled conditions. In all experiments, the endophytes were applied individually as seed dressings. Five endophytes could significantly reduce symptoms of Fusarium culmorum (Periconia macrospinosa E1 and E2, Epicoccum nigrum E4, Leptodontidium sp. E7 and Slopeiomyces cylindrosporus E18). In particular, treatment with Periconia macrospinosa E1 significantly reduced Fusarium symptoms on roots by 29–63% in two out of four experiments. Using, a gfp transformed isolate of P. macrospinosa E1, it was possible to show that the fungus was present on roots 14 days after sowing, coinciding with the disease scoring. To test for a potential systemic effect of the seed treatment, eight endophyte isolates were tested against the leaf pathogen Pyrenophora teres. Three isolates could significantly reduce symptoms of P. teres (Lasiosphaeriaceae sp. E10, Lindgomycetaceae sp. E13 and Leptodontidium sp. E16). Seed treatment with Lasiosphaeriaceae sp. E10 reduced net blotch leaf lesion coverage by 89%, in one out of three experiments. In conclusion, specific endophyte isolates exerted varying degrees of protection in the different experiments. Nevertheless, data suggest that endophytic strains from E. repens in a few cases are antagonistic against F. culmorum and P. teres, but otherwise remain neutral when introduced to a barley host in a controlled environment. Full article

(This article belongs to the Special Issue Plant Pathogenic Fungi)

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8 pages, 2358 KiB

Open AccessCommunication

Fusarium oxysporum Associated with Fusarium Wilt on Pennisetum sinese in China

by Jiaqi Zheng, Liyao Wang, Wenchao Hou and Yuzhu Han

Pathogens 2022, 11(9), 999; https://doi.org/10.3390/pathogens11090999 - 31 Aug 2022

Cited by 4 | Viewed by 6479

Abstract

Pennisetum sinese, a versatile and adaptable plant, plays an essential role in phytoremediation, soil reclamation, and fodder production. From 2018 to 2021, the occurrence of Fusarium wilt, with symptoms of foliar blight and internal discoloration of the stem, was observed in Chongqing, [...] Read more.

Pennisetum sinese, a versatile and adaptable plant, plays an essential role in phytoremediation, soil reclamation, and fodder production. From 2018 to 2021, the occurrence of Fusarium wilt, with symptoms of foliar blight and internal discoloration of the stem, was observed in Chongqing, China. Pathogens were isolated from the symptomatic leaves. Based on morphological characteristics as well as DNA sequences of the 18S ribosomal RNA (SSU), translation elongation factor 1-α (EF1-α), RNA polymerase II subunit 1 (rpb1), and RNA polymerase II second largest subunit (rpb2) genes, the causal agents were identified as Fusarium oxysporum. Phylogenetic analysis of the combined dataset of EF1-α, rpb1 and rpb2 showed that pathogenic isolates clustered with F. oxysporum strains. The pathogen was reisolated from inoculated and diseased tissues; thus, Koch’s postulates were fulfilled. This is the first report of F. oxysporum causing Fusarium wilt on P. sinese in China and worldwide. Full article

(This article belongs to the Special Issue Plant Pathogenic Fungi)

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Review

Jump to: Research

34 pages, 2549 KiB

Open AccessReview

The Devastating Rice Blast Airborne Pathogen Magnaporthe oryzae—A Review on Genes Studied with Mutant Analysis

by Jinyi Tan, Haikun Zhao, Josh Li, Yihan Gong and Xin Li

Pathogens 2023, 12(3), 379; https://doi.org/10.3390/pathogens12030379 - 26 Feb 2023

Cited by 13 | Viewed by 3600

Abstract

Magnaporthe oryzae is one of the most devastating pathogenic fungi that affects a wide range of cereal plants, especially rice. Rice blast disease causes substantial economic losses around the globe. The M. oryzae genome was first sequenced at the beginning of this century [...] Read more.

Magnaporthe oryzae is one of the most devastating pathogenic fungi that affects a wide range of cereal plants, especially rice. Rice blast disease causes substantial economic losses around the globe. The M. oryzae genome was first sequenced at the beginning of this century and was recently updated with improved annotation and completeness. In this review, key molecular findings on the fungal development and pathogenicity mechanisms of M. oryzae are summarized, focusing on fully characterized genes based on mutant analysis. These include genes involved in the various biological processes of this pathogen, such as vegetative growth, conidia development, appressoria formation and penetration, and pathogenicity. In addition, our syntheses also highlight gaps in our current understanding of M. oryzae development and virulence. We hope this review will serve to improve a comprehensive understanding of M. oryzae and assist disease control strategy designs in the future. Full article

(This article belongs to the Special Issue Plant Pathogenic Fungi)

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21 pages, 472 KiB

Open AccessReview

Wheat Genes Associated with Different Types of Resistance against Stem Rust (Puccinia graminis Pers.)

by Anatolii Karelov, Natalia Kozub, Oksana Sozinova, Yaroslav Pirko, Igor Sozinov, Alla Yemets and Yaroslav Blume

Pathogens 2022, 11(10), 1157; https://doi.org/10.3390/pathogens11101157 - 7 Oct 2022

Cited by 11 | Viewed by 3221

Abstract

Stem rust is one wheat’s most dangerous fungal diseases. Yield losses caused by stem rust have been significant enough to cause famine in the past. Some races of stem rust are considered to be a threat to food security even nowadays. Resistance genes [...] Read more.

Stem rust is one wheat’s most dangerous fungal diseases. Yield losses caused by stem rust have been significant enough to cause famine in the past. Some races of stem rust are considered to be a threat to food security even nowadays. Resistance genes are considered to be the most rational environment-friendly and widely used way to control the spread of stem rust and prevent yield losses. More than 60 genes conferring resistance against stem rust have been discovered so far (so-called Sr genes). The majority of the Sr genes discovered have lost their effectiveness due to the emergence of new races of stem rust. There are some known resistance genes that have been used for over 50 years and are still effective against most known races of stem rust. The goal of this article is to outline the different types of resistance against stem rust as well as the effective and noneffective genes, conferring each type of resistance with a brief overview of their origin and usage. Full article

(This article belongs to the Special Issue Plant Pathogenic Fungi)

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