Tomato chlorosis virus (ToCV), transmitted by the whitefly, Bemisia tabaci (Gennadius; Hemiptera: Aleyrodidae) has been continuously emerging on tomato plants and causing a significant economic loss throughout China. In the current study, RNA-Seq analysis was used to explore the gene expression profiles of B. tabaci Mediterranean (MED) that fed on both ToCV-infected and -uninfected tomato plants for 6, 12, 24, and 48 hours, respectively. The results revealed that dynamic changes occurred in the gene expressions of whiteflies at different time intervals after they acquired the virus. A total of 1709, 461, 4548, and 1748 differentially expressed genes (DEGs) were identified after a 6, 12, 24, and 48 hours feeding interval for the viral acquisition, respectively. The least number of expressed genes appeared in whiteflies with the 12 hours feeding treatment, and the largest numbers of those found in those with 24 hours feeding treatment. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that B. tabaci MED responded to ToCV acquisition through altering its nerve system development, fertility, detoxification, glucose metabolism, and immune function before it lost its ability to transmit the virus. The number of DEGs, degree of differential gene expressions, expression level of the same gene, involved biological processes, and metabolic functions in whiteflies post the 12 hours feeding, and viral acquisition were different from those from other three feeding treatments, which could be a significant finding suggesting an effective control of B. tabaci MED should be done less than 12 hours after whiteflies started feeding on ToCV-infected tomatoes. Our results further provided a clarified understanding in how B. tabaci was protected from viral acquisitions through comparison of the differential profile of gene expressions in whiteflies feeding on plants that were infected by semipersistent viruses.

Plastics are extensively applied in agricultural production, and exposure of crops to micro- and nano-plastics (MNPs) can markedly affect crop health. However, current understanding of the effects of particle size and concentration on the physiological and biochemical responses of plants remains limited. In this study, the effects of polyethylene micro-plastics (2 μm) and nano-plastics (200 nm) at varying concentrations in cherry radish were investigated. Plant biomass, physiological and biochemical responses, and the microspatial distribution and transport behavior of organic components at the soil-root interface were evaluated. The results demonstrated that high concentrations (150 mg/kg) of both micro- and nano-sized plastic particles significantly inhibited plant growth and photosynthetic performance, including reductions in chlorophyll content, net photosynthetic rate, and stomatal conductance. Notably, stress resistance indicators, such as soluble protein and soluble sugar, were affected, particularly at higher concentrations. SEM analysis directly verified the attachment of micro-plastic particles to root surfaces, whereas nano-particles were capable of penetrating root tissues. Synchrotron radiation-based FTIR imaging enabled in situ visualization of functional group distributions within the soil-root microenvironment, and semi-quantitative analysis further revealed a significant increase in carboxylic functional groups under nanoscale plastic exposure. This study also proposed a novel strategy to characterize the distribution and interactions of organic components within plant roots under MNP-induced stress. Overall, these findings offer new insights into the biological impacts and translocation potential of MNPs in crops, emphasizing their potential risks to agricultural production.

Tomato (Solanum lycopersicum) gray leaf spot disease is a predominant foliar disease of tomato in China that is caused mainly by the necrotrophic fungal pathogen Stemphylium lycopersici. Little is known regarding the pathogenic mechanisms of this broad-host-range pathogen. In this study, a comparative transcriptomic analysis was performed and more genetic information on the pathogenicity determinants of S. lycopersici during the infection process in tomato were obtained. Through an RNA sequencing (RNA-seq) analysis, 1,642 and 1,875 genes upregulated during the early infection and necrotrophic phases, respectively, were identified and significantly enriched in 44 and 24 pathways, respectively. The induction of genes associated with pectin degradation, adhesion, and colonization was notable during the early infection phase, whereas during the necrotrophic phase, some structural molecule activity-related genes were prominently induced. Additionally, some genes involved in signal regulation or encoding hemicellulose- and cellulose-degrading enzymes and extracellular proteases were commonly upregulated during pathogenesis. Overall, we present some putative key genes and processes that may be crucial for S. lycopersici pathogenesis. The abilities to adhere and colonize a host surface, effectively damage host cell walls, regulate signal transduction to manage infection, and survive in a hostile plant environment are proposed as important factors for the pathogenesis of S. lycopersici in tomato. The functional characterization of these genes provides an invaluable resource for analyses of this important pathosystem between S. lycopersici and tomato, and it may facilitate the generation of control strategies against this devastating disease.

Stemphylium lycopersici is the causal pathogen of the devastating tomato gray leaf spot with a wide range of alternative plant hosts. To mitigate its potential endemic in facility-cultivated tomatoes, novel disease control strategies should be attempted to minimize the use of chemical fungicides. In this study, we identified a metalloprotease from S. lycopersici genome and designated it as SlMEP1, as it appears to be a typical zinc metalloproteinase containing a WLM (WSS1-like metalloprotease) domain and a characteristic HEXXH motif, which we determined by analyzing its transcriptional profile and enzymatic functions. The transcription level of SlMEP1 increased greatly during the fungal invasion of tomato leaves. The deletion of the SlMEP1 gene from S. lycopersici hindered its mycelial growth and reduced its pathogenicity. An assessment of the functional dissection indicated that SlMEP1 induced cell collapse and inhibited the expression of the host chitinases, which consequently made tomato cells more susceptible to S. lycopersici and other pathogenic fungi.

Hawthorn (Crataegus pinnatifida) is an important economic fruit and Chinese medicinal plant, which is widely distributed in the northern China. In early July 2024, a fruit rot disease was observed on the young fruits of hawthorn in a park of Shouguang, Shandong Province, China (36°53'42.16″N, 118°47'22.4″E). Forty plants were surveyed (from approximately 120 trees), which had 15 to 30% of fruits infected. Diseased fruits displayed brown, sunken, approximately circular lesions. Small sections (3-4 mm) cut from the edges between the diseased and healthy tissue from 20 diseased fruits were surface sterilized by using 75% ethanol for 30 s, and rinsed thrice with sterile distilled water. The diseased tissues were then dried and plated onto potato dextrose agar (PDA) and incubated at 25°C in the dark. Cultures were purified by hyphal tipping. In total, 12 colonies were isolated from the necrotic tissues, and all of them showed similar morphological characteristics. The colonies were initially white, gradually turning gray-green to dark gray after 5 days. Conidia were hyaline, aseptate, ellipsoidal to obovoid, 20.1-29.3 × 5.0-8.3 μm, with an average of 24.2 × 6.6 μm (n = 30). These morphological traits suggested that the pathogen shares similarities with the Botryosphaeria dothidea (Zhang, et al., 2021). For accurate identification, three representative isolates (SGSZ-01 to SGSZ-03) were selected for molecular identification by amplifying and sequencing the internal transcribed spacer (ITS) region, translation elongation factor 1-alpha (TEF1-α), and β-tubulin (TUB2) with the primers ITS1/ITS4, EF1-728F/986R, and Bt2a/Bt2b (Carbone and Kohn 1999; Jia et al. 2019), respectively. GenBank accession numbers were PQ197601, PQ586368, and PQ586369 for ITS, PQ201924, PQ588676, and PQ588677 for TEF1-α, and PQ201925, PQ588678, and PQ588679 for TUB2, and gene sequencing showed 99.2 to 100% identity with the ex-type strain of B. dothidea (CMW 8000). Results from the maximum likelihood phylogenetic analysis, based on the three concatenated gene sequences, placed our isolates in a clade with B. dothidea. The pathogenicity of SGSZ-01 was conducted using a wound inoculation method on 11-week-old fruits of 10-year-old hawthorn trees both on living plants and detached fruits. All fruits were wounded with a sterilized needle and inoculated by placing 5 mm² agar plugs of 5-day-old cultures grown on PDA. Control fruits were treated with agar plugs. All the attached fruits were enclosed in a plastic bag with a wet cotton ball for 5 days. The same number of detached inoculated fruits were placed in Petri dishes on a piece of wet filter paper and incubated at 25°C. The pathogenicity test was conducted three times independently. Necrotic lesions (4.5 ± 0.3 mm in diameter) resembling natural infections were observed on fruits 7 days after inoculation, and no symptoms appeared on the control fruits. The pathogen was reisolated from the lesions and was identified by the methods described above. No pathogens were isolated from control fruits. Therefore, the pathogen of hawthorn fruit rot in China is B. dothidea. B. dothidea has previously been reported causing fruit rot on mango, plum, pomegranate fruit, and apple in China (Feng et al. 2023; Gu et al. 2020; Tang et al. 2012; Yuan et al. 2024). To our knowledge, this is the first report of B. dothidea causing fruit rot disease on C. pinnatifida. The information on identification of this fungus may be helpful to the control and prevention of the disease.