Plants are subject to attack and infection by a variety of pests and pathogens as they grow, and have evolved sophisticated and complex defense systems in response to pathogen invasions, which can trigger specific transcription factors for effective immune responses through multiple signaling pathways. The AP2/ERF (APETALA2/ethylene response factor) family members play important roles as plant-specific transcription factors in plant growth, development and biotic and abiotic stress responses. In this review, we summarized the classification, structural features, sequence recognition and functions of AP2/ERF transcription factors by referring to the relevant research progress in recent years at home and abroad, and focused on those of AP2/ERF transcription factors involved in plant disease resistance in the areas of transcriptional regulation, post-translational modification-phosphorylation regulation, secondary metabolite synthesis and hormone signaling. It provides a theoretical reference for the in-depth study of the regulation mechanism of AP2/ERF involved in plant disease resistance. Finally, the research and application prospects of AP2/ERF were discussed and prospected.
The occurrence of potyviruses and poleroviruses in vegetable crops is common, and seriously affects quality and yield. In order to develop environmental friendly and efficient plant virus inhibitors, potyviruses and poleroviruses were detected and analyzed using RT-PCR in suspected virus disease samples of vegetable crops such as Capsicum annuum, Solanum lycopersicum, Cucurbita moschata, Cucurbita pepo, Phaseolus vulgaris and Vigna unguiculata in Luoyang city. The results showed that the main viruses were pepper vein yellows virus (PeVYV) in pepper, potato virus Y (PVY) in tomato, and zucchini yellow mosaic virus (ZYMV) and cucurbit aphid-borne yellows virus (CABYV) in pumpkin and zucchini. Co-infection with ZYMV and CABYV was common. In kidney beans, melon aphid-borne yellows virus (MABYV) was detected, while no virus was detected in cowpea samples. Among them, the occurrence of ZYMV in pumpkin and zucchini was more serious, and kidney bean was found as a new natural host of MABYV for the first time. The phylogenetic analysis showed that the PVY-LYFQ isolate obtained in this study had a relatively distant relationship with other PVY isolates, and the genetic variability of PVY isolates was not closely related to their geographic locations or hosts, as well as the genetic variability of PeVYV isolates was not directly related to their geographic locations, but was related to their hosts to some extent; the genetic variability of ZYMV isolates were related to both their geographic locations and hosts to some extent; the genetic variability of CABYV and MABYV genome sequences was all related to their geographic locations. This study provides an important theoretical basis for the prevention and monitoring of potyviruse and poleroviruse diseases, the implementation of control measures, and the development of control drugs in vegetable crops in the Luoyang area.
The tomato leaves and fruits suspected to be infected with tomato brown rugose fruit virus (ToBRFV) were collected from the tomato planting area in Chifeng City, Inner Mongolia, in March 2024. RT-PCR technology was employed to amplify approximately 798 bp sequence with degenerate primers ToBRFV-MP-F/R to detect the presence of TOBRFV in this study. Furthermore, based on the sequencing results, the complete genome sequence of ToBRFV-NMG was obtained using four pairs of specifically designed primers. BLAST comparison showed that the cloned ToBRFV-NMG complete genomic nucleotide sequence shared the highest identity (99.86%) with the Shandong isolate of ToBRFV (ToBRFV-SD, GenBank accession number: MT018320). Phylogenetic trees showed that the genome sequence of the newly isolated ToBRFV-NMG was most closely related to the ToBRFV-SD isolate reported in Shandong in 2020. Both of them were clustered in the same branch, and they were also closely related to other isolates of Tobamovirus as well. Pathogenicity analysis showed that the virus infected tomato leaf was able to infect Nicotiana benthamiana, Capsicum annuum L., and Solanum lycopersium resulting in symptoms such as wrinkling, mosaic and necrosis that are consistent with those observed in the field. The viral sequence was determined by RT-PCR and was identical to the sequence of ToBRFV-NMG. These results confirm that the tomato fruits and leaves were infected by a ToBRFV isolate. This is the first report of tomato infected by ToBRFV in Inner Mongolia, which sheds light on the identification, prevention and control of local viral diseases.
Maize yellow mosaic virus (MAYMV) belongs to Polerovirus, a genus of sense single-stranded RNA viruses. It causes damages to corn and other gramineous crops, resulting in the manifestation of red leaves, dwarfing, deformity and other symptoms in maize plants. Maize is an important food crop in Anhui Province. The occurrence of maize yellow mosaic virus has led to a decline in maize yield. In 2023, a sampling survey was conducted across 16 maize planting areas in Anhui Province. MAYMV incidence in various sampling regions was detected using RT-PCR, and the full-length sequences of the coat protein and movement protein genes (CP and MP, respectively) were amplified. Further analysis was conducted to assess the mutation rates of the CP and MP amino acid sequences from the sampled regions, and a phylogenetic tree for the CP and MP was constructed with MEGA 6. These allowed an analysis of the occurrence and genetic diversity of MAYMV in Anhui Province. The results indicate that MAYMV is generally present and harmful to maize in Anhui Province, with 13 out of 16 sampled regions testing positive for the virus, showing an infection rate ranging from 20% to 100%. Additionally, the CP and MP of MAYMV were relatively conserved across regions, with CP amino acid mutation rates ranging from 0 to 0.01, and MP amino acid mutation rates ranging from 0 to 0.05. Phylogenetic analysis also revealed that MAYMV isolates in the Anhui region are genetically closely related.
In some regions of Jilin Province, large scale outbreaks of nematode disease in foxtail millet (Setaria italica) have caused serious damage. Pathogenic nematodes were isolated and identified from 10 samples collected across various regions of Jilin Province. Nine samples yielded pathogenic nematodes who morphological characteristics and measured values for both female and male nematodes were consistent with those described for Aphelenchoides oryzae by Subbotin. The post-vulva to sac of females comprised 23.5% (19.3%-25.5%) of the distance from the vulva to the anus, featuring 4 lateral lines and 3-4 branches at the tail end. Molecular identification, based on comparison of the ribosomal 28S rDNA D2-D3 region and the cytochrome c oxide subunit I (COI) gene in mitochondria, along with phylogenetic tree analysis, revealed that the 9 samples of nematodes clustered with the A. oryzae, for ming a sister clade with A. besseyi. In summary, the nematode isolated from millet ears in Jilin Province was identified as A. oryzae. Clarifying the pathogen of millet nematode and its associated symptoms lays the foundation for effective prevention and control of millet nematode disease.
CELL BIOLOGY, PHYSIOLOGY, BIOCHEMISTRY, AND MOLECULAR BIOLOGY
In the study, a metacaspases gene was islated from the cDNA library of the interaction between the wheat cultivar ‘Suwon 11’ and Puccinia striiformis West. f. sp. tritic Eriks.＆ Henn.(Pst). The gene was designed as TaMCA3. Through transient overexpression experiments, it was found that the TaMCA3 gene can effectively inhibit cell necrosis induced by the cell necrosis inducer BAX. The protoplast subcellular localization experiment showed that the TaMCA3 protein is mainly distributed in the cytoplasm. During the compatible interaction between wheat and Pst, it is shown that TaMCA3 participates in the susceptibility process of wheat to Pst. After using VIGS (virus-induced gene silence) technology to transiently silence TaMCA3, in comparison to the control plants, the silenced plants exhibited obvious necrotic spots on their leaves, and the number of urediniospore pustules of Pst CYR31 was significantly reduced. This indicates that silencing TaMCA3 can significantly enhance wheat′s resistance to Pst CYR31. Furthermore, by using yeast two-hybrid screening identified TaASP, a left-handed aspartate protease, was identified as the interacting target of TaMCA3. In vitro and in vito protein interaction experiments confirmed the interaction between TaASP and TaMCA3. This discovery provides new insights for a deeper understanding of the specific functions and mechanisms of TaMCA3 in the interaction between wheat and Pst.
In this study, hyphal growth rate and spore production methods were used to determine the indoor inhibitory effect of difenoconazole on Coryneum populinum. Morphotoxicology and transcriptome sequencing were used to analyze the treatment of Differentially expressed genes (DEGs) after treatment with difenoconazole for exploring the antibacterial mechanism of difenoconazole. The results showed that the higher the concentration of difenoconazole treatment, the greater the inhibition effect on C. populinum with lower rates of colony growth and sporulation. After treatment with difenoconazole, 618 DEGs were obtained from C. populinum. GO enrichment analysis showed that DEGs were the most abundant in cell anatomical entities, essential components of membranes, intrinsic components of membranes, and carbohydrate metabolism. KEGG enrichment analysis showed that alanine, aspartic acid and glutamate metabolism, MAPK (mitogen-activated protein kinase) signaling, ribosomal biosynthesis and metabolism were all in the first 20 enrichment pathways. Twenty-six key genes were up-regulated and nine key genes were down-regulated in MAPK signaling, including Ste2, Cdc42, Ste18 and Mcm1 in the Fus3/Kss1 signaling pathway (P<0.05), Cdc42 in the HOG signaling pathway (P<0.05), and CWI signaling pathways Wsc1, Slt2 and Fks2 in the up-regulated manners (P<0.05). The results provided data support for revealing the response mechanism of C. populinum to difenoconazole stress and research basis for the further development of synergistic agents of triazole fungicides.
The monopartite geminiviral V2 protein plays an important role in the viral infection process. Howe-ver, there are few studies on the function of the AV2 protein of bipartite geminiviruses. This study investigated the interaction between the bipartite tomato leaf curl Hsinchu virus (ToLCHsV) AV2 protein and the Nicotiana benthamiana Ran binding protein 1-2b (NbRanBP1-2b), and analyzed their effect on the pathogenicity of the virus. Bimolecular fluorescence complementation (BiFC), GST pull-down and subcellular co-localization were used to validate the interaction between ToLCHsV AV2 and NbRanBP1-2b. NbRanBP1-2b was observed to localize at both the cell membrane and cytoplasm. When ToLCHsV AV2 co-localized with NbRanBP1-2b, the original localization of AV2 and NbRanBP1-2b was altered. After inoculated with ToLCHsV, N. benthamiana leaves exhibited wrinkling, accompanied by delayed growth and development. Furthermore, the relative expression level of NbRanBP1-2b exhibited a gradual increase. When NbRanBP1-2b was silenced by tobacco rattle virus (TRV) or overexpressed by potato virus X (PVX), the virus accumulation in the inoculated N. bentha-miana plants was relatively decreased. These results indicate that ToLCHsV can effectively utilize NbRanBP1-2b to promote virus infection by interacting with its AV2 protein during infection.
To explore the genetic patterns of Puccinia striiformis f. sp. tritici (Pst) populations in Qinghai Province, China, in this study, wheat leaves infected by Pst from various regions and at different infection stages were collected, with a particular focus on the plants in the early stages of disease development. Through virulence phenotype analysis, the virulence diversity among the Pst isolates was clarified. Additionally, population genetic diversity was analyzed based on the SSR and SNP molecular markers, exploring the genetic structure of the Pst populations within different regions and the degree of differentiation between populations. The results indicated that the sources of Pst in Qinghai Province during the spring, summer, and autumn are complex and diverse, exhibiting abundant virulence phenotypes and high virulence diversity, with strong pathogenicity. There was significant gene flow among the Pst populations in different counties in Qinghai Province, with the populations in Guide, Datong, Xunhua, and Jianzha displaying unique and diverse pathotypes. The Pst populations in Hualong may contain sexual populations, potentially contributing to the virulence variation of Pst. This study elucidates the genetic characteristics of Pst populations in Qinghai Province, providing theoretical support for the integrated control of wheat stripe rust in the region.
The bacterial canker disease of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa) has developed into an important limiting factor for kiwifruit production in Anhui province. Samples with typical bacterial canker symptoms were collected in the main kiwifruit orchards from five counties in Anhui province in 2022-2023. A total of 124 Psa isolates were obtained using the dilution plate methods, and subjected to further analysis via repetitive-element PCR genomic fingerprinting (rep-PCR) techniques. The results revealed that three rep-PCR primer pairs amplified 34 clear bands, among which 26 exhibited polymorphism. Based on sampling location, the isolates were divided into five groups, with effective allele numbers, Nei’s gene diversity index, and Shannon index at the species level being 1.19, 0.13, and 0.21, respectively. The highest genetic diversity was observed among the Psa isolates from Jinzhai, while the lowest was found from Huoqiu. UPGMA cluster analysis indicated that the 124 Psa isolates could be classified into three major groups at a genetic similarity coefficient of 0.80, with no significant correlation between group classification and geographical origin of strains. Pathogenicity tests showed that 72 isolates were classified as highly virulent, intermediately virulent,weekly virulent and avirulent strains, accounting for 59.72%, 25%, 5.56%, and 9.72% of the total, respectively. Virulence differentiation was observed among isolates from the same geographical location, host species, or organ, but no significant correlation was found between virulence differentiation and strain origin. Additionally, the insertion of ISPsy36 into the hrpS gene was detected in four avirulent strains, suggesting that the disruption of the type III secretion system (T3SS) function by transposon insertion is one of the primary reasons for the loss of virulence in Psa strains in the field.
To investigate the causal agent of leaf blight occurred on Piceaasperata Mast, diseased samples were collected in Dalian, Liaoning Province, and tissue isolation was performed. The pathogenicity of the representative isolates was verified by Koch′s postulates. The pathogen was identified as Nothophoma quercina according to morphological characteristics and multi-gene (ITS, RPB2, TUB2, and LSU)-based phylogenetic analysis result. The growth of N. quercina on different culture media, carbon sources, nitrogen sources, tempera-tures, light conditions, and pH values was determined. The results showed that N. quercina grew best on SDA culture medium, with soluble starch as carbon source and urea as nitrogen source, at 25°C, pH 7.0, and a 12 h light/12 h dark cycle. Ten pesticides were tested for their in vitro antifungal activity against N. quercina, and 98% pyraclostrobin TC showed the best inhibitory effect, with an EC50 value of 0.0196 μg·mL-1. Five pesticides with higher inhibitory effects were selected for further field efficacy trials. It was showed that the best control effect was achieved by using 250 g·L-1 pyraclostrobin EC, with an efficacy of over 65% in July and September. The results lay a basis for further investigating the occurrence regularity and chemical control of the disease.
Cotton Verticillium wilt, caused by Verticillium dahliae, poses a devastating threat on cotton production worldwide. In order to explore new biocontrol resources, this study isolated 213 actinomycete strains from healthy cotton soil. Among these, 22 strains exhibited antagonisticactivity against the highly pathogenic V. dahliae strain Vd592, as determined by dual-culture plate assays and inhibition zone measurements. Three strains with the strongeset antagonistic effect were selected for further study and were identified based on morphological characteristics and 16 S rDNA sequences analysis, and determined for their disease prevention and growth promoting effects on cotton. Results indicate that strain 126 and 2-59 are Streptomyces rectiolaceus, with strain 2-59 showing the highest biocontrol efficacy, achieving a relative prevention effect of 62.72% in pot experiments. Strain 73 was identified as Streptomyces amritsaransis and demonstrated the most significant plant growth-promoting effects, increasing plant height, fresh weight, and dry weight by 8.38%, 16.99%, and 36.82%, respectively. Overall, all three strains exhibited both biocontrol and growth-promoting activities, highlighting their potential to be developed as biocontrol agents against cotton Verticillium wilt.
Tomato canker, caused by Clavibacter michiganensis subsp. michiganensis (CMM), is a severe and difficult-to-manage vascular bacterial disease threatening tomato production. This study aimed to identify highly effective biocontrol agents against CMM, and a bacterial strain ZF516 exhibiting significant antagonistic activity against the pathogenwas obtained from tomato rhizosphere. Through morphological observation, physiological and biochemical characterization, and phylogenetic analysis based on multi-gene sequences, ZF516 was identified as Bacillus velezensis. Genomic analysis revealed that the ZF516 genome harbors antibiotic biosynthetic genes encoding lipopeptide antibiotics such as surfactin, macrolactin, fengycin, difficidin, bacillibactin, bacillaene, bacilysin, and iturin. Other biocontrol trait analysis showed that strain ZF516 has the ability to produce protease and siderophore, and solubilize phosphate. Antimicrobial spectrum assays demonstrated that ZF516 effectively inhibited the growth of 6 pathogenic fungi and 6 pathogenic bacteria. Furthermore, pot trials indicated that ZF516 achieved a control efficacy of 78.70% against tomato bacterial canker, higher than that achieved by treatment with thiazole zinc. In summary, strain ZF516 represents the first reported B. velezensis strain exhibiting promising biocontrol efficacy against tomato bacterial canker.
Ovulinia azaleae Weiss is listed in Chinese quarantine pest and Ovulinia petal blight caused by Ovulinia azaleae brings about significant damage to Rhododendron simsii. A precise enzyme mediated duplex exponential amplification (EmDEA) assay was developed for detection of O. azaleae in this study. Based on ITS gene of O. azalea and related species, the combination of DNA primers and RNA probes was designed and screened in this study. The minimum detection limit was 1.00 pg per 20 μL reaction system. The detection results of suspected sample indicated this method is easy to operate, rapid, and highly specific, which provides an important reference for the detection and screening of O. azaleae in the port.
In order to rapidly detect tobacco mild green mosaic virus (TMGMV), three sets of RT-LAMP primers based on the conserved sequence of TMGMV coat protein gene were designed to screen and determine the optimal primer combination. The single-variable method was used to optimize the reaction temperature and reaction time. RT-LAMP was then compared with RT-PCR to verify the specificity of the optimized detection, sensitivity and practical application in the field, and the TMGMV RT-LAMP rapid detection technology system was established. The results showed that the optimal reaction condition for RT-LAMP was to amplify at 65 °C for 60 min. The sensitivity of the optimized RT-LAMP was 1 000 times higher than that of RT-PCR, and 1.65×10-2 copies·μL-1 template could be detected. There was no cross-reaction with other related viruses during the detection process. The detection results of 60 Rehmannia glutinosa samples showed that the detection rate of the RT-LAMP method (100%) was higher than that of RT-PCR (83.3%). Therefore, the RT-LAMP detection technology established in this study can be used for rapid detection of TMGMV.
Turfgrass is an essential component of urban greening, sports, and relaxation, whose health directly affects the aesthetics of cities and the quality of residents’ life. The leaf spot caused by Alternaria leads to the leaf yellowing of turfgrass and thus finally dying away, which threatens its health of turf and reduces the value of ornamental application. In this study, nine isolates of Alternaria were isolated from the diseased leaves of turfgrass, which were collected from turf of urban green space, golf course, and soccer field. Based on morphological characteristics and molecular method, the nine isolates were assigned to two species, namely A. alternata (four strains) and A. tenuissima (five strains). All the nine isolates could infect the leaves of Poa pratensis, causing leaf spot disease, with the average disease incidence and disease index of 100% and 14.32, respectively. This is the first report about Alternaria causing leaf spot disease on turfgrass.
Sugar beet is one of the important sugar crops, providing significant value on agricultural production in China. The seedling stage healthiness guarantees the productivity of sugar beets. During May 2020 and 2021, a new leaf spot disease was observed in sugar beet seedlings of paper-pot nursery seedling cultivation area in Ulanqab, Inner Mongolia Autonomous Region. A fungal strain and four bacterial strains were isolated and purified from the symptomatic seedling samples and the pathogenicity were verified by Koch′s postulate. The morphologic characters and phylogenetic reconstruction indicated that the novel seedling disease was caused by the co-infection of Pseudomonas syringae and Fusarium oxysporum. In this study, we identified the causal agents of the seedlings stage disease in Ulanqab, which provides theoretical guidance for prevention and control of seedling diseases and reducing the loss of sugar beet.
The Orah mandarin, a thick-skinned citrus variety originating from Israel, has been introduced to several citrus-producing regions in southern China in recent years. In March 2022, black rot symptoms were observed on approximately 10% of Orah mandarin fruits in a storage facility in Wuhan City, Hubei Province, China. The fungus was isolated from the diseased tissue and identified based on morphological characteristics and multi-gene sequence analyses, including the large subunit (LSU), the nuclear ribosomal internal transcribed spacer (ITS), beta-tubulin (β-tubulin), and RNA polymerase II (rpb2) genes. The causal organism was identified as Stagonosporopsis pogostemonis, a fungal species not previously reported on Orah mandarin. Pathogenicity tests fulfilled Koch’s postulates, confirming S. pogostemonis as the pathogen responsible for the black rot symptoms. This is the first report of S. pogostemonis causing black rot disease in citrus fruits worldwide.
A leaf blight disease seriously affecting the quality and yield of Alpinia katsumadai Hayata was discovered at the Academy of Tropical Agricultural Sciences Nursery Agriculture Base, Chinese Academy of Tropical Agricultural Sciences, Danzhou City, Hainan Province. The pathogen AH-1, which caused the disease, was isolated from the disease lesion of Alpinia katsumadai Hayata. Based on both morphological characteristics and phylogenetic analysis of multiple gene sequences, including β - tubulin (TUB2), internal transcriptional spacer (ITS), and ribosomal subunit (LSU), this pathogen was further identified as the species Neoscirrhia mateuciicola. The study of this pathogen provides a basis for the prevention and control of Alpinia katsumadai Hayata leaf blight.
During a survey in 2020, cucumber plants in Shandong province displayed yellowing and chlorotic symptoms on leaves. In order to identify the pathogen, eight samples were collected, and PCR was used to test for virus species. The full-length genomic sequences of DNA-A and DNA-B of SLCCNV (squash leaf curl China virus) were cloned, and their phylogenetic relationships were also analyzed. The analysis confirmed the presence of both CCYV(cucurbit chlorotic yellows virus) and SLCCNV in the collected samples. The DNA-A of the SLCCNV genome was 2 735 nt in length, while the DNA-B of SLCCNV was 2 717 nt (GenBank accession no. OM258181 and OM258182). Further results showed that the DNA-A and DNA-B formed an independent cluster and were mostly related to the SLCCNV isolates that reported in China. This is the first systematic report of SLCCNV infecting cucumber in China.
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
