Peanut (Arachis hypogaea), which is widely cultivated across the world, provides high-quality vegetable oil, protein, dietary fiber, minerals, and vitamins for humans. However, in field conditions, the peanut is easily affected by various biotic and abiotic stresses. Diplodia gossypina is the dominant pathogen causing severe collar rot on peanuts. To dissect the pathogenic mechanism of D. gossypina, genome sequencing analysis was performed by using the D. gossypina strain A20_4. The sequencing data showed that the genome assembly size of D. gossypina A20_4 is 43.03 Mb with a GC content of 54.91%. The de novo assembly identified a total of 10,745 genes, containing 41,526 coding sequences and 2.20% of repeat sequences, of which 6,461 genes (60.13%) were annotated using BlastP from GO annotation, 3,245 genes (30.20%) and 3,093 genes (28.79%) were annotated from KOG and KEGG annotations, respectively. Meanwhile, the secreted proteins and effectors in 10,745 protein sequences encoded by the whole genome of D. gossypina A20_4 were analyzed, and the results showed that there are 790 secreted protein genes including 220 carbohydrate-active enzymes and 224 potential effector proteins. The functions of 222 potential effector proteins can be annotated by PHI-base. According to the annotation results, 12 key pathogenic factors were identified in D. gossypina A20_4. Moreover, a serine/threonine protein kinase SNF1 gene required for autophagy process was identified and analyzed. Deciphering the whole genome of D. gossypina A20_4 provides us with novel insights into understanding evolution, pathogenic molecular mechanism, host-pathogen interaction, and many other complexities of the pathogen.

Tomato leaf curl New Delhi virus (ToLCNDV) is a newly discovered begomovirus in China, which transmitted by whitefly (Bemisia tabaci). It was first discovered in Zhejiang and Shanghai, and then discovered in Jiangsu. It seriously affected the local production of cucurbitaceae crops. In this study, a watermelon isolate collected from Nantong, Jiangsu Province was detected by PCR, and rubbed onto Nicotiana benthamiana, tomato, watermelon, melon and cucumber. The inoculated plants exhibited symptoms such as curling and chlorosis, indicating that this virus strain could be mechanically transmitted. The whole genome amplification and sequence analysis of this isolate showed that it had the closest genetic relationship with the isolate previously reported in China and clustered into the same branch of the phylogenetic tree. Systematic evolution also showed a correlation between the evolution of the virus and its geographic location, which indicated that ToLCNDV in China might originate from Indian. There was no evidence of recombination in any of the Chinese isolates. This study will serve as a reference to study the origin, evolution, mutation, and control of the virus.

As one of the major vegetable crops in Shanxi Province, tomato plants are constantly suffering from various virus infections, which severely limit tomato yield and quality. To determine the virus species and infection types on tomato plants, 154 samples exhibiting virus-like symptoms were collected from 7 cities and subjected to small RNA sequencing combined with PCR/RT-PCR for virus detection and identification. A total of six viruses were identified from these tomato samples. According to the detection rate from high to low, they were cucumber mosaic virus (CMV) (85.71%), tomato yellow leaf curl virus (TYLCV) (45.45%), southern tomato virus (STV) (41.56%), and tomato mosaic virus (ToMV) (27.27%), potato virus Y (PVY) (25.97%) and tomato chlorosis virus (ToCV) (18.18%). Among them, CMV was the dominant virus infecting tomato plants in Shanxi Province. Analysis of infection types showed that a total of 32 types were classified from the above samples, including 4 types of single virus infection and 28 types of mixed infection. Among them, CMV, CMV+ToMV, CMV+STV+TYLCV, CMV+PVY+STV, CMV+TYLCV, CMV+STV+ToCV+TYLCV and CMV+PVY were the most common types, with detection rates of 16.23%, 10.39%, 9.09%, 8.44%, 5.84%, 5.84%, and 5.19%, respectively and mainly exhibited mosaic, narrowing, chlorosis and leaf curling symptoms. Analysis of CMV satellite RNA (satCMV) association revealed that 66.23% of samples in 22 viral infection types were associated with satCMV, and samples in 10 infection types were partially associated with satCMV. Combined with the field symptoms, we found that CMV, CMV+ToMV and CMV+PVY+STV-infected samples showed severer symptoms, and CMV+STV showed milder symptoms in the presence of satCMV, and samples of other infection types exhibited no obvious symptom changes when associated with satCMV. Phylogenetic analysis showed that the pairwise identity of the 10 satCMV isolates from Shanxi was 93.4%-100%, and clustered with isolates from China and Greece. In this study, we identified 6 viruses and 1 satellite RNA in tomato plants in Shanxi Province, among which PVY and STV were reported in Shanxi tomato plants for the first time. And we comprehensively analyzed the relationship between virus infection types and field symptoms, providing an important reference for the rapid diagnosis and control of tomato virus diseases.

High-throughput sequencing has become a crucial tool for advancing our understanding of fungal genomics and transcriptomics. However, accurately assessing gene expression levels from RNA sequencing (RNA-Seq) data necessitates the precise mapping of short sequence reads back to their correct locations in the reference genome. Sequenced strains often exhibit sequence variations from the reference genome strains, and due to the reference genome containing only one type of nucleotide information at any given locus, reads carrying alternative nucleotide information will have at least one mismatch with the reference genome, leading to mapping biases during the read alignment. To address this bias, researchers have developed various software and algorithms. Nevertheless, the applicability of these methods for fungal RNA-Seq data remains unclear. In this study, we took Fusarium graminearum, an important plant pathogenic fungus, as an example. Utilizing both simulated and real RNA-Seq data of this fungus, we comprehensively assessed the mapping biases and mapping rates of various mapping methods when dealing with single nucleotide polymorphisms (SNPs), RNA editing, and sequencing errors in reads. The results indicate that the graph-based genomic approach using the vg software outperforms others, demonstrating optimal performance. This method requires lower sequencing depth and significantly reduces mapping biases caused by polymorphic sites while improving reads mapping rates. These findings provide a reference for the analysis of complex fungal RNA-Seq data.

Carya illinoensis is an important non-timber forest species in China, and one of the most serious diseases caused by Colletotrichum spp. dangerously threaten the development of the pecan industry. In order to investigate the pathological mechanism of Colletotrichum spp. in pecan, C. fructicola B-5 was used to establish and applied the genetic transformation system. The results showed that mycelium was cultured in CM medium for 20 h, 1% lysing enzyme was lysed at 30 °C for 3 h. The production of protoplasts was up to 8.92×10⁶ cells·mL^-1. Using PEG-mediated protoplast transformation, the plasmid with the resistance gene and GFP gene can be transferred into B-5 protoplasts, and the biological characteristics of the positive transformant B-5(GFP) did not change significantly. The B-5(GFP) strain was used to analyze the infection dynamics of Colletotrichum spp. on the host leaves. The results showed that the conidia began to germinate on the surface of the host after 9 h, began to infect the host mesophyll tissue after 48 h, and a large number of primary hyphae were produced after 96 h, and the infected part showed cell death. The genetic transformation system of C. fructicola in pecan was successfully established in this study, and the infection dynamics of C. fructicola B-5(GFP) on pecan were preliminarily clarified, which laid a foundation for subsequent pathogenic mechanism analysis and prevention and control.

In this study, an infectious clone of zucchini yellow mosaic virus (ZYMV) was constructed, and the differentially expressed genes (DEGs) of ZYMV-infected Cucumis melon were analyzed via RNA-Seq technology. The RNA was extracted from the leaves of ZYMV-infected C. melon, the 3 segments divided from the full genome of CGMMV were cloned separately by using RT-PCR, and then the ZYMV infectious clone was constructed through homologous recombination. Healthy C. melon was inoculated with pCB-ZYMV, typical mosaic symptoms were observed in the C. melon at 7 days post inoculation (dpi), and ZYMV CP protein could be detected by Western blot. The total RNAs extracted from the ZYMV-infected and healthy C. melon leaves, respectively, were sent to the biotech company for high-throughput transcriptome sequencing analysis. A total of 3 108 differentially expressed genes (DEGs) were screened, of which 1 558 were up-regulated and 1 550 were down-regulated. GO, COG annotation and KEGG pathway analysis revealed the involvement of many DEGs in host plant carbohydrate transport and metabolism, plant signal transduction, plant-pathogen interactions, starch and sucrose metabolism, and MAPK cascade response and other physiological metabolic pathways related to disease resistance. To validate the RNA-seq results, the differential expression of eight genes were examined by qRT-PCR, which was basically consistent with the transcriptome results. This study is of great significance for elucidating the molecular mechanism of ZYMV resistance in melon and breeding selection of ZYMV resistant melon varieties.

Bioinformatics methods were used in this study to explore the key ZjDELLA genes that are responsive to JWB (Jujube witches′ broom) phytoplasma infection in jujube plants based on the ‘Junzao’ genome information. Forty-three ZjGRAS TFs (ZjGRAS1-ZjGRAS43), which were divided into 9 subfamilies, were identified, and 4 of them were identified as jujube DELLA subfamily (ZjDELLA) TFs. According to the functional prediction network of ZjDELLA we constructed, jujube DELLA protein might play a role in GA signal transduction pathway. The expression of ZjDELLA1, ZjDELLA2 and ZjDELLA4 were significantly up-regulated, while ZjDELLA3 was significantly down-regulated in response to JWB phytoplasma infection. Additionally, heterologous expression of ZjDELLA4 in Arabidopsis could induce leaflet and dwarf phenotypes. To further investigate the mechanism underlying ZjDELLA4-inducing dwarfism in Arabidopsis, quantitative real-time PCR (qPCR) analysis was performed to determine the expression patterns of GA signal transduction-related genes. It was found that ZjDELLA4 significantly up-regulated the expression of GID1A, GID1B and GID1C, while significantly suppressed the expression of SPY. The results indicate that ZjDELLA4 may induce abnormal growth phenotypes in Arabidopsis by interfering with GA signal transduction.

The antifungal activity of dark segmented endophytes (DSE) in blueberry roots against Fusarium oxysporum was investigated through the plate confrontation assay, double plate technique, and control effect experiment. The results showed that all the 8 DSE strains could successfully colonize in blueberry roots, leading to the inhibition of F. oxysporum with a maximum inhibition rate of 74.03%. Both volatile substances and fermentation filtrate produced by these 8 DSE strains exhibited certain inhibitory effect on mycelial growth of F. oxysporum, with the highest inhibitory rate of 37.25% for volatile substances and 66.13% for 50% concentration of fermentation filtrate. In the control efficacy test, sterile blueberry tissue seedlings were firstly treated with a certain DSE strain before inoculation with F. oxysporum. The strains FL1 (Thozetella neonive), MJY26 (Phalocephala fortinii), and MF4 (Phalocephala fortinii) showed good biocontrol effects on root rot caused by F. oxysporum, with control effects of 72.76%, 75.86%, and 77.93%, respectively. Inoculation with FL1, MJY26, and MF4 strains significantly increased the activities of phenylalanine ammonia lyase, polyphenol oxidase, and peroxidase antioxidant in blueberry, and also root vigor of these blueberry seedlings, thereby reducing stress caused by F. oxysporum. The DSE strain MF4 showing best inhibitory effect against F. oxysporum was selected for further test. This strain showed a prevention and control effect of 79.27% on Fusarium root rot of blueberry seedlings in pot experiment. The results lay an important foundation for developing DSE microbial agents against blueberry root rot caused by F. oxysporum.

Cotton Verticillium wilt is a major soil borne disease in cotton production, which seriously endangers the yield and quality of cotton. There are two pathotypes of pathogens, defoliating and non-defoliating. The defoliating strains cause cotton leaves to be yellowing, wilting, and defoliating, while the non-defoliating strains only exhibit yellowing and wilting, but without defoliating. The threatening to cotton industry caused by the defoliating Verticillium dahliae strains has been increasing year by year in China. Multiple plant hormones are involved in the physiological defoliation process of cotton, but the function of plant hormones in the pathological defoliation process of cotton is not yet clear. This study analyzed hormone levels, the tissue-specific expression patterns and levels of key genes in hormone pathways, in cotton plants infected with defoliating strain XJ592 and non-defoliating strain XJ511. The functions and variation patterns of plant hormones in the defoliation process were also clarified. Results showed that salicylic acid and ethylene play a positive regulatory role in the process of cotton defoliation induced by V. dahliae, while jasmonic acid, auxin, and cytokinin play a negative regulatory role. Multiple plant hormones co-regulate cotton defoliation.

Plant disease specimens are important for the research and teaching of plant pathology. However, plant disease specimens made by conventional methods are prone to discoloration, being damaged, making it difficult to preserve for long periods. In this study, we used a combined method of vacuum lyophilized technology and crystal resin dripping technology to prepare specimens of a telial horn and jelly-like state of a telium of the apple rust fungus. This method is low-cost, and effective, by which plant disease specimens that are made can be preserved for a long term, being maintained the original morphological characteristic and color of plant tissue and the pathogens. It also provides a plant disease preparation method being used in teaching courses or related aspects to plant pathology.

Lasiodiplodia theobromae is the dominant pathogen in grapevine canker disease. However, due to the immaturity of the genetic transformation system of L. theobromae and the phenomenon of multinucleated complete genome sequences, it has not been possible to obtain homozygous mutant of L. theobromae. The construction method of L. theobromae homozygous mutant was established to lay the foundation for the subsequent gene function research of L. theobromae. In this study, L. theobromae LtAGO1 gene was used as the knockout target, and the upstream and downstream homologous arms of the LtAGO1 gene were constructed into the knockout vector of PKOV21 vector by double-joint PCR; L. theobromae strain CSS-01s was prepared by enzyme protoplast preparation; and the knockout vector was transferred into L. theobromae protoplasts by polyethylene glycol-mediated protoplast transformation; finally, the homozygous strain of LtAGO1 mutant was screened by PCR. Compared with the traditional homologous recombination method for constructing pure knockout mutants of filamentous fungi, this study focused on changing the process of transformant screening. On the basis of the LtAGO1 heterozygous mutant obtained by the previous screening with homologous recombination, the protoplast was re-prepared by picking the mycelial tip, and the protoplast was diluted in concentration for another homologous recombination screening. Compared with the conventional homologous recombination method, the probability of obtaining L. theobromae pure heterozygous mutants was improved, and the L. theobromae homozygous LtAGO1 knockout mutant was successfully obtained. Meanwhile, the LtAGO1 mutant strain showed accelerated growth rate and significantly enhanced virulence compared with the wild type. The construction of homozygous mutants in this study lays the foundation for investigating gene in L. theobromae.

Pythium deliense is an important phytopathogenic oomycete that causes serious damages on a variety of crops such as tobacco, soybean and mung bean. To develop a loop-mediated isothermal amplification (LAMP)-based system for rapid and specific detection of P. deliense, four LAMP primers and one loop primer were designed with the 3-phosphoglyceric phosphokinase gene (Pgk) as the target gene. The specificity and sensitivity of these primers were confirmed, and the system was also successfully applied to detect P. deliense in soybean tissues after artificial inoculation and natural infection. The nucleic acid amplification reaction was carried out at 63 ℃ for 60 min under isothermal conditions, and the dye HNB (hydroxynaphthol blue) was added before the amplification. In the specificity test, sky blue color (positive reaction) was developed only in the presence of Pythium deliense, while purple color was developed (negative reaction) for the other tested oomycete and fungal strains. The minimum detection limit of the system was 100 pg·μL^-1 for detecting genomic DNA and 10 oospores in 0.25 g soil for detecting the pathogen in soil. This LAMP-based system provides a technique for specific detection of P. deliense and rapid diagnosis of the disease it caused.

Anthracnose caused by Colletotrichum cereale is a major disease affecting the yield and quality of oats. Establishing accurate and rapid detection method is a key for timely monitoring and controlling this disease. In this study, specific primers ITS-2F/ITS-2R, designed based on ITS region sequence, were combined with the universal primers ITS1/ITS4 to form nested PCR primers. Under the optimized reaction conditions and reaction systems, a single bright target band of 287 bp could be stably amplified with the lowest detection DNA concentration at 1 fg·μL^-1. The method was successfully used to detect C. cereale in oat leaf, seed and soil samples of oat planting field. The method is rapid, accurate, efficient and sensitive, and can be used for field diagnosis and detection of oat anthracnose, providing scientific basis for disease prevention and control in time.

In the quest for early and rapid detection of barley yellow dwarf virus-GAV (BYDV-GAV), recombinase polymerase amplification (RPA) primers and lateral flow dipstick (LFD) probes were meticulously designed and screened to target the BYDV-GAV CP gene. The RT-RPA detection method was meticulously established, optimized, and assessed for sensitivity and specificity. The findings highlighted the efficient amplification of BYDV-GAV template utilizing the GAV-RPA-F4/R4 and GAV-RPA-F6/R6 primers, with subsequent detection on LFD using the GR-nfo-pb4 and GR-nfo-pb6 probes. The optimal reaction conditions for the RT-RPA assay included 2.5 μL of MgAc, 29.5 μL of RPA buffer, 2.4 μL each of primer-F and primer-R (concentration 10 mmol·L^-1), 2.5 μL of cDNA, and 11.2 μL of RNase-free ddH₂O in a 50.0 μL reaction system, with incubation at 37 ℃ for 25 minutes. Amplification was conducted using a PCR instrument. The RT-RPA method consistently detected BYDV-GAV, with a detection threshold of 2.3×10^-2 ng·μL^-1 (6.03×10⁶ copies·μL^-1) aligning with that of RT-PCR. Notably, the RPA method exhibited specific amplification for BYDV-GAV, showing no cross-reactivity with other pathogens like BYDV-PAV, BYDV-GPV, wheat dwarf virus (WDV), and wheat blue dwarf (WBD), all causing yellowing dwarf symptoms in wheat. Employing the RPA detection method, 57.8% (11/19) of plants were tested positive for BYDV-GAV in wheat samples displaying yellowing and dwarfing symptoms in the field. These results underscored the potential of the established RT-RPA method for the early and swift detection of BYDV-GAV in wheat fields.

Tomato mottle mosaic virus (ToMMV) is a new member of the genus Tobamovirus discovered in recent years. It mainly infects solanaceae plants such as tomato, pepper, and eggplant, seriously affecting fruit yield and quality. In this study, the specific primers of recombinase-aided amplification (RAA) and the crRNA of clustered regularly interspaced short palindromic repeats/CRISPR-associated 12a (CRISPR/Cas12a) were designed based on the conserved sequence of the coat protein sequence of ToMMV, and the reporter gene was selected. By optimizing the reaction system and validating the specificity and sensitivity, rapid, sensitive and visual method for ToMMV detection was established. The detection signal was strongest when the final concentration of fluorescent reporter FQ was 300 nmol·L^-1, the Cas12a/crRNA ratio was 1∶5, and the final concentration was 200 nmol·L^-1and 1 000 nmol·L^-1. With only 15 min of RT-RAA and CRISPR/Cas12a reaction respectively, positive signals can be directly observed under a portable blue light irradiation equipment. The results of the actual samples showed that the assay established in this study could detect ToMMV in pepper and tomato. This method can be used for the specific detection of ToMMV, and the minimum detection limit in detecting the total RNA of ToMMV containing samples is 2.5 pg·μL^-1, suggesting that this method is 100 times more sensitive than the RT-PCR-based ToMMV detection. Hence, the RT-RAA-CRISPR/Cas12a-based detection established here is a rapid, sensitive and visual method for ToMMV detection.

Onion yellow dwarf virus (OYDV) is one of the major viruses that pose a threat to the yield and quality of Allium crops. The establishment of an efficient OYDV detection method is of great significance for the prevention and control of OYDV diseases in Allium crops. In this study, 8 strains of monoclonal antibodies against OYDV were generated. With the best matching monoclonal antibody 3D3, a sandwich ELISA (enzyme linked immunosorbent assay, ELISA) method for the detection of OYDV was established, and the reaction conditions were optimized. The sensitivity of 3D3 for the OYDV-infected shallot leaves was 2 560 fold dilution, and the lowest detection limit of the purified recombinant OYDV coat protein was 11.71 ng·mL^-1. In addition, 3D3 had no cross reaction with shallot latent virus or shallot yellow strip virus in the infected Allium crops. The consistency rate between 3D3-based sandwich ELISA and RT-PCR method was 96%. With the OYDV sandwich ELISA method established in this study, OYDV samples and detection antibody were incubated at the same time. Thus, the detection steps were simplified, and the detection process can be completed within 1 h. The establishment of the sandwich ELISA method for the detection of OYDV provided technical support for the detection of OYDV, production of virus-free seed balls and identification of resistant germplasm resources.

Wheat stripe rust is one of the airborne fungal diseases that threaten the safety of wheat production. The emergence of new races of Puccinia striiformis f. sp. tritici (Pst) leads to the loss of the resistance of wheat cultivars, and causes disease epidemics due to its rapid accumulation and spread in oversummering variable areas of the pathogen. Qinghai Province is an important oversummering epidemic area of wheat stripe rust in China, in which the causal agent Pst can infect Berberis to complete sexual cycle. Therefore, determining the proportion of Pst infecting Berberis plants in Qinghai Province under natural conditions is very important to understand the roles of alternative host Berberis being attacking by the sexual reproduction of Pst and providing inoculum causing stripe rust on wheat. In this study, 1860 aecial samples collected from Berberis growing in main wheat-planting areas in Qinghai Province from 2022 to 2024 were used to determine Pst using combined methods of inoculation on susceptible wheat cultivar and detection with the Pst-specific molecular markers. As a result, the isolation rates of Pst from aecial samples in the three years were 2.72%, 4.10% and 2.38%, respectively, with an average of 3.07%. The detection rates based on molecular markers were 23.22%, 27.42% and 20.48%, respectively, with an average of 23.71%, with the highest isolation rate and detection rate in 2023. Therefore, in Qinghai Province Pst can infect the alternative host Berberis to complete sexual reproduction under natural con-ditions, with a high proportion. The results provide a clue for understanding the generation of new races of Pst and the origin of inoculum causing wheat stripe rust. Thus, it is necessary to strengthen effective management of sexual reproduction of Pst in the oversummering variable area in Qinghai Province for the prevention and control of wheat stripe rust in the local and national areas.

Root rot was found in main durian-planting areas in Hainan Province. The symptoms include root and root crown rot, which resulted in reduced tree vigor (leaf yellowing, leaf drop), branch wilt, even the death of entire tree. This causes serious economic losses to durian production. To identify the causal agent of this disease, diseased root samples of durian trees were collected from Sanya, Ledong, Lingshui and Baoting in Hainan Province from 2023 to 2024, and tissue isolation method was used to obtain potential pathogens. Based on morphological characteristics, phylogenetic relationship inferred from rDNA-ITS, Ypt1, β-Tubulin and EF-1α, and the result of pathogenicity test, the pathogen was identified as Phytophthora palmivora. This is the first report of durian root rot caused by P. palmivora in China.

A stem rot disease was found on Ficus virens and Ficus concinna in Hainan Province, China, in 2022. The diseased plants showed symptoms of sparse crowns with chlorotic leaves and dead branches, and even died when severely damaged. Yellow brown semi-circular basidiocarps were usually observed at the base of diseased trees in rainy and humid seasons. To identify the causal agent of the disease, conventional tissue isolation methods was adopted for pathogen isolation from diseased samples, and the representative strains HNQHHGR20221003001 and HNDXXYR2023051804 were used for pathogenicity test and morphological and molecular identification. Based on morphological characteristics, phylogenetic relationship inferred from rDNA-ITS, SSU and LSU, and the result of pathogenicity test, the pathogen was identified as Ganoderma australe. This is the first report of stem rot caused by G. australe on Ficus microcarpa in China. The results provide a basis for the control of the disease.

In the newly built apple orchard in Shilin County in central Yunnan, the incidence rate of apple root rot exceeded 20% and had been increasing by more than 10% annually, resulting in significant financial losses for fruit farmers. This study aims to clarify the pathogen and whether there are new pathogenic bacteria, so as to develop comprehensive prevention and control technologies and curb the epidemic of the disease. Samples of typical diseased plants were collected and subjected to tissue isolation methods for the isolation of pathogenic bacteria. The pathogenicity of the bacteria was confirmed through inoculation tests, and their preliminary classification was based on morphological characteristics. Furthermore, molecular biology identification was conducted using multilocus genes including internal transcribed spacer (ITS), β-tubulin (β-TUB), and histone H3 (HIS3). Through a combination of morphological and molecular biology identification methods, the pathogen responsible for apple root rot was conclusively identified as Ilyonectria vredehoekensis. This discovery represents the first report of apple root rot caused by I. vredehoekensis, laying a foundation for developing epidemic monitoring and integrated control technologies to manage this disease outbreak.

In 2021, a tea plant leaf spot disease was found in the Jin Xuan tea plants( Camellia sinensis cv.Jinxuan). A representative strain was isolated from the diseased leaves according to Koch’s postulates. The isolates were further identified as Cladosporium cladosporioides based on morphological characteristics and phylogenetic analysis with internal transcribed spacer region (ITS) and β-Actin gene. The results showed that the pathogen causing the disease was Cladosporium cladosporioides. This is the first report of Cladosporium cladosporioides in tea plants in China

Morus alba is an important economic tree. In 2023, a new foliar disease of mulberry tree occurred in Longchuan of Yunnan Province, China. Irregularly shaped brown spots were exhibited on the surface of infected leaves, with small black dots on the adaxial surfaces of blotches. In pathogenicity test, small brown lesions were observed surrounding the inoculation sites of wounded leaves after 5 days, resembling the symptoms that occurred in the field. The conidia of the pathogen are fusiform, erect or slight curving, with 4 septa, 1-4 hyaline apical appendages and a size of (22.11-26.58) μm×(4.62-6.31) μm long. Based on morphological characteristics and multi-locus phylogenetic analysis involving internal transcribed spacer (ITS), translation elongation factor 1 gene (tef1) and beta tubulin gene (tub2), and pathogenicity test result, the pathogen of mulberry leaf spot was identified as Pestalotiopsis camelliae. To our knowledge, this is the first report of P. camelliae causing leaf spot on mulberry tree in China.

Soft rot of konjac was found in main konjac-planting areas in Shangluo region of Shaanxi Province, China. The symptoms include petiole and corm rot, which result in leaf yellowing and wilt, even the death of entire plant. This has caused serious economic losses to konjac production. To identify the causal agent of this disease, petiole and corm samples of konjac with typical symptoms of soft rot were collected from Shanyang, Danfeng and Shangnan counties in Shangluo region from 2023 to 2024, and tissue isolation method was used to obtain potential pathogens. Based on morphological and biochemical characteristics, phylogenetic relationship inferred from full genome and the 16S rRNA sequence, and the result of pathogenicity test, the pathogen was identified as Raoultella ornithinolytica. This is the first report of konjac soft rot caused by R. ornithinolytica in the world.

Areca palm latent totivirus 1 (APLTV1) is a newly discovered virus that infects areca palms in Hainan Province. The objective of this study is to reveal the molecular evolutionary characteristics of the APLTV1 population in this province. Thirty-one randomly selected APLTV1-positive samples were subjected to genome sequence amplification, followed by sequence and phylogenetic analyses. The complete sequences of the 31 APLTV1 isolates from Hainan were all determined to be 4764 nucleotides in length, sharing a high sequence identity of 98.02% to 99.12% with the representative XS-3 isolate of APTLV1. Within the APLTV1 genome, two open reading frames (ORFs) were identified encoding the coat protein (CP) and the RNA-dependent RNA polymerase (RdRp), respectively. Negative selection was found at the majority of polymorphic sites within the RdRp and CP genes, whereas positive selection was found exclusively at polymorphic sites within the CP gene. Phylogenetic analysis revealed that all isolates of APLTV1 could be separated into two distinct clades. The results obtained from this study provide valuable insights into understanding the epidemiology and molecular variation of APLTV1.