The fungal genus Verticillium is closely related to vascular bundle diseases in plants, and it includes several important plant pathogenic fungi such as Verticillium dahliae, V. albo-atrum and V. longisporum. Certain Verticillium spp. experienced genomic evolution by inter-specific crosses within the genus leading to an approximate doubling of the genome size and gave rise to allodiploid hybrid V. longisporum, a serious pathogen that severely affects cruciferous plants. Compared with other Verticillium species, V. longisporum exhibits longer conidia, approximately twice the nuclear DNA content, and a higher evolutionary rate. This study reviews the taxonomic status, geographical distribution, host range, morphological characteristics, and symptoms of V. longisporum. It also explores the research progress in detection and prevention of this pathogen. Currently, the prevention and control of this pathogen is difficult, and chemical fungicides cannot provide effective control. Therefore, strict implementation of quarantine measures is the most effective approach to prevent the spread of this pathogen.
To investigate the species composition and pathogenicity of Fusarium pathogens causing maize ear rot in Shanxi Province, a total of 1 238 diseased ear samples were collected from 51 cities/counties/districts across four geographical regions (Northern, Central, Southern, and Southeastern Shanxi) during 2022-2024. From these samples, 1 430 single-spore isolates were obtained. The pathogens were identified using a combination of morphological and molecular biological methods. The results showed that Fusarium was the dominant genus, comprising 1 229 isolates and accounting for 85.94% of the total isolates. Eleven Fusarium species were identified, including F. verticillioides, F. proliferatum, F. subglutinans, F. graminearum, F. boothii, F. oxysporum, F. incarnatum, F. equiseti, F. poae, F. sporotrichioides, and F. acuminatum, with isolation frequencies of 52.73%, 20.34%, 8.62%, 6.02%, 5.53%, 4.39%, 1.06%, 0.98%, 0.16%, 0.08%, and 0.08%, respectively. The composition and isolation frequency of Fusarium species varied by region and year. F. verticillioides was the most widely distributed species across all regions in Shanxi Province and maintained the highest isolation frequency throughout the study period. Pathogenicity tests demonstrated that F. graminearum was the most virulent, with an average disease rating and disease index of 7.39 and 82.07, respectively. In contrast, F. verticillioides and F. subglutinans exhibited comparatively weaker virulence, with average disease ratings of 2.55 and 1.93, and disease indices of 28.30 and 21.38, respectively. These findings offer a theoretical basis for breeding resistant varieties and developing integrated control strategies for maize ear rot in Shanxi Province.
Gastrodia elata is a precious Chinese medicinal herb, and Zhaotong is a genuine producing area for G. elata. However, tuber rot disease severely restricts the sustainable development of this industry. In this study, pathogenic fungi were isolated and purified from diseased G. elata samples collected in Zhaotong City, Yunnan Province. Through morphological and molecular identification, combined with pathogenicity tests, the pathogen causing G. elata tuber rot disease was identified as Mariannaea lignicola. Analysis of the biological characteristics revealed that the optimal conditions for mycelial growth of M. lignicola were oatmeal agar (OA) medium, pH 7.0, 32 °C, and complete darkness, while the optimal conditions for conidial production were potato dextrose agar (PDA) medium, pH 6.0, 28 °C, and full light. Using Czapek-Dox medium as the basal medium, the effects of different carbon and nitrogen sources on the growth and sporulation of M. lignicola were investigated. It was found that soluble starch as the carbon source and nitrogen deficiency promoted the fastest mycelial growth, while soluble starch as the carbon source and yeast extract as the nitrogen source were more conducive to sporulation. The pathogen can produce cell wall-degrading enzymes (CWDEs) including carboxymethyl cellulase (CMCase), polygalacturonase (PG), and polymethylgalacturonase (PMG). The activity of these enzymes was significantly higher in diseased tissues than in healthy tissues, indicating that CWDEs play a key role in enabling M. lignicola to infect Gastrodia elata and cause tuber rot disease. This study is the first to report M. lignicola as the pathogen of G. elata tuber rot disease in China, providing a theoretical foundation for the integrated control of this disease.
Fusarium graminearum is the primary pathogen causing wheat scab. The heat shock protein Hsp30, an ATP-independent molecular chaperone, binds to partially denatured proteins, facilitating their correct refolding and preventing irreversible damage. In this study, we used homologous recombination to generate the knockout mutant of FgHSP30 (ΔFgHsp30) and its complemented transformant ΔFgHsp30-C. Our results indicated that compared to the wild-type strain PH-1, the growth rate and colony morphology of the ΔFgHsp30 mutant exhibited no significant changes. However, its conidial yield decreased by approximately 49%, accompanied by alterations in the number of conidial septa. RT-qPCR analysis revealed that the FgHSP30 gene was up-regulated in the early stage of wheat infection by F. graminearum. The pathogenicity test demonstrated that the pathogeni-city of the ΔFgHsp30 mutant was significantly reduced in wheat compared to the wild type. Furthermore, toxin detection showed that the biosynthesis of DON toxin in the ΔFgHsp30 mutant was inhibited, with a notable reduction in the transcription levels of TRIs genes. Additionally, RT-qPCR results showed that the FgHSP30 gene was highly expressed under elevated temperature conditions, while the ΔFgHsp30 mutant exhibited severe impairment in heat shock resistance. In summary, the heat shock protein FgHsp30 plays a crucial role in the asexual reproduction, high-temperature stress response, pathogenicity, and toxin production of F. graminearum.
Phytophthora capsici is a destructive pathogen that infects hundreds of crop species within the Cucurbitaceae, Solanaceae, Leguminosae, and Malvaceae families, leading to substantial economic losses. While epidermal growth factor (EGF) is well-studied in animal systems, its role in plant-pathogen interactions is less clear. Our previous study found that P. capsici secretes an EGF-like protein (PcEGFL1) into the pepper apoplast; however, its function was not characterized. Therefore, we cloned the full-length coding sequence of PcEGFL1 and analyzed its sequence characteristics, phylogenetic relationships, transcriptional expression, subcellular localization, and its effect on plant resistance. The results revealed that PcEGFL1 has a coding sequence of 1 002 bp, encoding a protein containing a signal peptide and two EGF domains. Its transcription was significantly up-regulated during the early infection stage of P. capsici, and the protein was localized to the plant apoplast. Transient expression of PcEGFL1 in Nicotiana benthamiana leaves induced immune responses—including a reactive oxygen species (ROS) burst, callose deposition, and up-regulation of defense-related genes such as NbPTI5—resulting in enhanced resistance to P. capsici. Consistent with this, the recombinant PcEGFL1 protein expressed and purified from Escherichia coli also exhibited elicitor activity. Collectively, these results indicate that PcEGFL1 is recognized by host plants as a pathogen-associated molecular pattern (PAMP) during early infection, thereby triggering immune responses. This study lays a foundation for further investigation into the function of PcEGFL1 and the pathogenicity mechanisms of P. capsici.
Sugarcane mosaic virus (SCMV) is the most important cause of maize dwarf mosaic disease in China. The co-infection of SCMV and maize chlorotic mottle virus (MCMV) can cause maize lethal necrosis. To investigate the genetic diversity and variation of SCMV populations in maize plants with SCMV single-infection, and with co-infection of SCMV and MCMV, we used the high throughput sequencing technology to analyze the virus inoculation effect in maize hosts. Under the two infection conditions, the single nucleotide polymorphism sites of the SCMV population were similar on the genome, but significant differences were observed in the HC-Pro and NIa-Pro regions. A total of 447 and 442 substitution sites were identified in SCMV populations from single- and co-infected maize plants, respectively. Interestingly, the number of substitution sites in HC-Pro region of SCMV population from co-infected plants (83 sites) is much less than that from single-infected plants (105 sites), whereas more substitution sites in NIa-Pro region were observed in SCMV population from co-infected maize plants (29 and 46 sites in single- and co-infected maize plants, respectively). Notably, in both SCMV populations, the high levels of substitution rates were observed in CI region. There were 41 and 38 non-synonymous substitutions observed in SCMV populations from single- and co-infected maize plants, respectively. Further, Agrobacterium co-infiltration assay was utilized to confirm that the HC-Pro mutant with substitution of R99 to C which resulted from a specific C-to-T transition, with a substitution rate of 0.075%, lost its RNA silencing suppressor activity. This study provides evidence for further understanding the population evolution mechanism of SCMV under different infection environments and for exploring the important roles of HC-Pro and NIa-Pro in the occurrence of MLN through artificial mutation.
To investigate the prevalence of lily mottle virus (LMoV) in lilies from Nanping City, Fujian Province, RT-PCR assay was employed to detect 48 infected leaf samples. From a subset of LMoV-positive samples, coat protein (cp) gene was amplified, cloned and sequenced. The obtained sequences were comparatively analyzed with all available published LMoV cp sequences to assess sequence variation and phylogenetic relationships. RT-PCR results showed that 32 out of 48 (66.7%) lily samples tested positive for LMoV, indicating widespread prevalence of the virus in Nanping City, Fujian Province. Using a specific primer pair LMoV-F/LMoV-R, the expected fragments were successfully amplified from 14 randomly selected positive samples. These sequences showed 86.34% to 99.88% nucleotide identity with the previously reported LMoV isolates. Phylogene-tic analysis classified all LoMV isolates into three distinct groups (Group I, Group II and Group III), with our 14 isolates forming a well-supported cluster within Group I. Phylogeny-trait association analysis revealed that isolates from the same region tend to cluster together, suggesting a possible correlation between LMoV diversification and geographic origin. Bayesian skyline plot (BSP) analysis showed that China LMoV population remained stable before 2010, but subsequently underwent dramatic expansion, followed by a recent slight decline which warrants continued monitoring due to its potential impacts on lily production. This study provides important insights into LMoV prevalence, molecular characteristics and population dynamics in Nanping City, Fujian Province, establishing a foundation for epidemiological monitoring and control strategies.
Phytophthora sojae causes root rot primarily through its zoospores, which sense soybean root-secreted isoflavones (genistein and daidzein) to locate and infect the host. Previous studies have identified the genistein receptor PsIRK1 and the daidzein receptor PsIRK3 in this pathogen and further identified esculetin as a specific antagonist that disrupts the PsIRK1-mediated chemotactic response. However, compounds capable of simultaneously interfering with chemotaxis induced by both isoflavones have remained unexplored. This study aimed to screen natural small-molecule compounds that inhibit the chemotactic effects of both genistein and daidzein. Chemotaxis interference assays showed that 6-hydroxycoumarin, at a concentration of 100 μmol·L-1, significantly disrupted zoospore chemotaxis toward both isoflavones. Mechanistic studies revealed that this interference depends on the PsIRK3-dependent pathway but does not involve direct receptor binding. Quantitative real-time PCR (qPCR) analysis indicated that 6-hydroxycoumarin treatment significantly downregulated PsIRK1 and PsIRK3 expression to 43% and 58% of control levels, respectively. Furthermore, the compound inhibited mycelial growth of P. sojae. Pot experiment results demonstrated that treatment with 100 μmol·L-1 6-hydroxycoumarin significantly enhanced the survival rate of soybean seedlings under P. sojae infection to 50%. This study identifies 6-hydroxycoumarin as a novel chemotaxis-interfering agent that mitigates P. sojae-induced root rot by suppressing chemoreceptor gene expression and hindering mycelial growth, providing a new strategy for ecologically sustainable disease control based on disrupting pathogen perception.
Verticillium dahliae is the causal agent of potato Verticillium wilt disease, a disease that significantly reduces potato yield and quality. To explore novel biocontrol resources against this disease, a bacterial strain designated Z-7, which exhibited strong antagonistic activity against V. dahlia, was isolated and screened from maize rhizosphere soil. Based on morphological characteristics and phylogenetic analysis, strain Z-7 was identified as Bacillus amyloliquefaciens. Further investigations revealed that volatile organic compounds (VOCs) produced by this strain strongly inhibited V. dalhliae: they significantly reduced mycelial biomass, induced abnormal hyphal morphology (including swelling, surface roughness, and collapse), and markedly decreased conidial germination rate. Additionally, the VOCs inhibited microsclerotia formation and melanin synthesis, and significantly down-regulated the expression of genes related to these processes. Analysis of the VOCs composition via gas chromatography-mass spectrometry (GC-MS) identified 11 compounds, with amines and 2,5-dimethylpyrazine (2,5-DMP) being the most abundant. Indoor toxicity assays showed that 2,5-DMP caused hyphal malformation and fragmentation in V. dahliae. Pot inoculation experiments demonstrated that this compound effectively reduced the disease index of potato Verticillium wilt without adversely affecting potato growth. In conclusion, strain Z-7 and its volatile metabolite 2,5-DMP exhibit strong biocontrol potential against potato Verticillium wilt. This study provides new microbial resources and a theoretical basis for the biocontrol of this disease.
Citrus canker, caused by Xanthomonas citri subsp. citri (Xcci), is a devastating bacterial disease in citrus production. Current control strategies primarily rely on copper-based compounds and antibiotics, yet their overuse poses increasing environmental and health risks. In recent years, phage-based biocontrol strategies have gained widespread attention due to their high specificity and environmental friendliness. In this study, a lytic bacteriophage named SAC was isolated from soil samples usingthe double-layer plate method with Xcci strain N8 as the host. The whole-genome sequencing results revealed that the SAC genome encodes 55 genes. Sequence alignment indicated that this bacteriophage belongs to the class Caudoviricetes. Transmission electron microscopy revealed that SAC has an icosahedral head approximately 60 nm in diameter, and belongs to the family Podoviridae within the order Caudovirales. Biological characterization showed that SAC lysed all 14 tested Xcci strains from diverse origins, yielding a lytic rate of 100%; the optimal multiplicity of infection (MOI) was determined to be 0.001, resulting in a phage titer of 4.5 ×1011 PFU·mL-1; SAC remained stable within a temperature range of 4-60 ℃ and a pH range of 4-11, but exhibited sensitivity to ultraviolet radiation; one-step growth curve analysis indicated a latent period of 60 min, a burst period spanning 60 to 160 min, and a burst size of 430 PFU·cell-1. In liquid culture, the addition of SAC significantly suppressed the growth of Xcci N8, as the bacterial concentration initially increased briefly and then continued to decrease, remaining at a low level. In planta experiments demonstrated that spraying SAC effectively inhibited the growth and spread of Xcci N8 in citrus plants. These results indicate that phage SAC exhibits strong inhibitory effects against Xcci and Xcci-induced citrus canker and has great potential to be developed as a novel biocontrol agent.
Salvia miltiorrhiza is an important traditional Chinese medicinal herb. Its sustainable production is severely threatened by root rot disease, which leads to significant yield losses and quality deterioration. Root rot in Salvia miltiorrhiza is a complex disease caused by multiple pathogens, primarily including Fusarium solani (Fs), F. proliferatum (Fp), and F. oxysporum (Fo). To establish a rapid and accurate resistance evaluation technology against the disease, this study systematically compared inoculation methods, pathogen combinations, conidial concentrations, and disease assessment timing. An optimized in vitro resistance evaluation system was developed: wounding-spray inoculation with an equal-volume mixed conidial suspension (at a concentration of 1×107 spores·mL-1) of the three pathogens (Fs+Fp+Fo), with disease assessment conducted at 6 days post-inoculation. Using this system, 19 S. miltiorrhiza accessions from 5 provinces were evaluated for resistance. Combined with pot and field validation experiments, 3 highly resistant accessions (ZD1, NY4, and NY17) and 4 resistant accessions (NY5, NY6, NY9, and NY21) were identified, accounting for 47.37% of the total materials. The in vitro evaluation results showed 84% consistency with field resistance performance, demonstrating that this method reliably reflects the true resistance level of S. miltiorrhiza germplasm to root rot. This study provides an efficient evaluation technology and valuable resistance resources for breeding root rot-resistant S. miltiorrhiza.
The chromosome number and genomic structure of Puccinia striiformis f. sp. tritici provide a fundamental molecular basis for its biological characteristics and pathogenic variability. In this study, Kompetitive Allele-Specific PCR (KASP) primers based on Single Nucleotide Polymorphism (SNP) variation sites identified from the genome assembly of the pathogen′s 18 chromosomes, were designed. A total of 64 pathogen isolates from regions including Qinghai, Gansu, Ningxia, Yunnan, Guizhou, and Sichuan were analyzed to assess polymorphism indices and population genetic structure, followed by Discriminant Analysis of Principal Components (DAPC). In total, 631 944 SNP sites were identified, 349 KASP-SNP primer pairs were designed, and 52 pairs with high polymorphism were ultimately selected. The average Polymorphism Information Content (PIC) of the selected primers was 0.639, and the average Gene Diversity (GD) was 0.695, representing improvements of 84.7% and 65.5%, respectively, compared to the 43 KASP primers previously developed in the laboratory. The DAPC results revealed that the genetic relationships among the populations from Yunnan, Guizhou, and Sichuan were relatively close, while those from Qinghai, Gansu and Ningxia exhibited stronger genetic affinities. The KASP-SNP markers developed in this study demonstrate high polymorphism and have broad potential for application.
The occurrence of guava wilt and branch blight severely impacts the development of the guava industry, and early diagnosis of infected plants is critical for disease control. In this study, based on the sequences of Nalanthamala psidii (causing guava wilt), Neopestalotiopsis egyptiaca and Neofusicoccum sinoeucalypti (the latter two associated with branch blight), we designed specific primers and detected the pathogens using singleplex, duplex, and triplex PCR. A triplex PCR detection system was established and applied to field samples. The results showed that this system simultaneously detected three pathogens with high specificity and sensitivity, with a detection limit of approximately 40 copies. The system successfully enabled rapid and accurate detection of pathogens in field samples. This study developed a multiplex PCR system for the simultaneous detection of pathogens causing guava wilt and branch blight, providing technical support for early disease diagnosis and control.
Watermelon silver mottle virus (WSMoV) is a spherical RNA virus that was caused serious damage to cucumber industry, so it is urgent to establish a monitoring and control system to prevent its spread. Based on the conserved region of nucleocapsid protein gene of WSMoV, an efficient real-time fluorescent quantitative polymerase chain reaction (qPCR) was established with the specific primer pair of WSMoV-qF3/R3, the optimal primer concentration of 10 μmol·L-1 and the optimal annealing temperature of 60.0 ℃. The recombinant plasmid was diluted into a standard at a 10-fold ratio, and the standard curve y=-3.159 3x + 41.62 was obtained. The cycle threshold of the qPCR standard curve was linear with the logarithm of the copy number of the template concentration, and the correlation coefficient was 0.990 3. The specificity of the established qPCR system is strong. The sensitivity of this assay was 1 000 times higher than that of conventional RT-PCR, and the limit of detection by qPCR was 4.63×102 copies·μL-1. The established qPCR was used to detect WSMoV in 60 cucumber samples collected from Shandong Province, with conventional RT-PCR used as a reference method, and the results showed that more positive samples were detected by qPCR (47, 78.33%) than by RT-PCR (42, 70.00%). The established qPCR detection system can be used for the rapid and quantitative detection of WSMoV.
During an investigation of pests and diseases affecting garden plants in Chongqing’s urban areas, severe leaf spot disease exhibiting typical anthracnose symptoms was observed on hydrangeas, resulting in extensive leaf yellowing and wilting. Two morphologically distinct Colletotrichum strains, designated ELXQ and BLXQ, were isolated and purified from symptomatic leaves of Hydrangea japonica. Pathogenicity tests confirmed both strains as causal agents, fulfilling Koch's postulates. Based on integrated morphological characteristics and multi-locus phylogenetic analyses using the ITS, GAPDH, CHS and ACT gene regions, strain BLXQ was identified as Colletotricum gloeosporioids and ELXQ as C. fioriniae, respectively. Among the seven broad-spectrum fungicides tested, 25% pyraclostrobin and 45% prochloraz showed the strongest inhibitory effects against strains BLXQ and ELXQ, with EC50 values of 2.2874 mg·L-1 and 2.7105 mg·L-1, respectively. These were followed by 50% carbendazim and 25% pyraclostrobin, which exhibited EC50 values of 4.3385 mg·L-1 and 2.9817 mg·L-1 against the two strains, respectively. These three fungicides were identified as promising candidates for controlling hydrangea anthracnose. Our findings provide crucial information on pathogen identification and fungicide selection, establishing a basis for developing effective management strategies against this disease.
Panicummiliaceum L., a minor cereal crop, is widely cultivated in arid and semi-arid regions of China. In 2024, a leaf blight disease was observed in this crop in Shanxi Province. Initial symptoms included fusiform lesions on the sheaths and elliptical lesions with irregular concentric rings on the leaves, both of which eventually causing leaf blight. Based on morphological characteristics, multilocus phylogenetic analysis (ITS, GAPDH, and EF-1α), and pathogenicity assays, the pathogens were identified as Bipolaris yamadae. Our study provides a scientific basis for further research on the prevention and control of this disease.
To identify the pathogen causing malformation and chlorosis symptoms in common lilac (Syringa vulgaris L.), a complete genome sequence of lilac leaf chlorosis virus China isolate (LLCV-China) was determined by deep sequencing of a small RNA library constructed from LLCV-infected samples using rapid amplification of cDNA ends (RACE) PCR. RNA1-RNA3 of LLCV-China were determined to be 3 434 nt, 2 773 nt and 2 267 nt in length and shared 44.22%-66.15%, 33.78%-62.74% and 34.96%-59.84% sequence identity with the members of the genus Ilarvirus, respectively. Phylogenetic analyses based on its four open reading frames (ORFs) indicated that LLCV-China clustered together with the previous reported LLCV isolates. This is the first report of a complete genome sequence of LLCV from China, which provides a foundation for the future research of LLCV.
In China, Hydrangea species have long been cultivated as ornamental plants. Recently, a severe leaf spot disease affected Hydrangea macrophylla plants in Chengdu, Sichuan Province, and caused a significant decline in their economic value. In this study, the pathogen was isolated and identified through morphological observation, sequence analysis of the small subunit (SSU) and D2-D3 expansion regions of the large subunit (LSU) of ribosomal RNA, and verified by Koch’s postulates, which confirmed Aphelenchoides fragariae as the causative agent of the disease. This finding marks the first documented case of A. fragariae causing leaf spot disease on hydrangeas in China. The results provided a scientific foundation for developing effective control strategies against this pathogen-caused hydrangea leaf spot disease.
Meloidogyne hispanica is one of the most important invasive plant root-knot nematode (RKNs). In this study, we present the de novo sequencing and assembly of its complete mitochondrial genome (mitogenome). The circular mitogenome spans 17 572 bp with an A+T content of 83.43% and encodes 36 genes: 12 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and two ribosomal RNA genes (rRNAs). PCGs mostly use standard ATN and TAN start/stop codons. Analysis of Ka/Ks ratios across the 12 PCGs within the genus Meloidogyne revealed distinct evolutionary signatures: COX1 exhibited the slowest evolutionary rate, whereas ND2 and ND6 showed accelerated evolution. Comparative genomic analysis revealed that the intergenic region between ND4 and ATP6 is the determinant of mitochondrial genome size in Meloidogyne species. The maximum-likelihood phylogenetic analysis based on the concatenated nucleotide sequences of the 12 PCGs from 23 species in the Nemata was performed. The phylogenetic analysis revealed that M. hispanica clustered within a distinct monophyletic clade of Meloidogyne species, with Meloidogyne oryzae exhibiting the greatest genetic divergence from other Meloidogyne species. This study provides the first mitochondrial genome sequence of M. hispanica. By integrating phylogenomic inference and evolutionary rate analysis, our findings establish a foundational dataset for further evolutionary study of Meloidogyne.
Fresh samples of Lagerstroemia indica showing flat stem and leaflet symptoms indicative of phytoplasma infection were collected in Xuzhou, Jiangsu Province. Transmission electron microscopy revealed spherical phytoplasma particles (500-800 nm in diameter) within the phloem of infected stems. Nested PCR amplification targeting the phytoplasma 16S rRNA gene yielded approximately 1.2 kb fragments from all 10 sampled specimens. The associated phytoplasma was designated Lagerstroemia indica fasciation phytoplasma (LiFP). Nucleotide sequence identity analysis indicated that the 16S rRNAgene of L. indica fasciation phytoplasma shares 99.92% identity with Paulownia witches′-broom phytoplasma strain sdyz (GenBank accession No. KP662133.1) and SDJX (OP107405.1) strain. Phylogenetic trees reconstructed from 16S rRNA showed that L. indica fasciation phytoplasma is closely related to members of group 16SrI. Furthermore, RFLP analysis and similarity coefficient calculations confirmed its classification into 16SrI-B subgroup.
Journal Information
Superintendent： China Association for Science and Technology
Sponsored by： Chinese Society for Plant Pathology
China Agricultural University
Editor in Chief: FAN Jun
Started in 1955
ISSN 0412-0914
CN 11-2184/Q
