Cucumber mosaic virus (CMV) is a virus that can infect various monocotyledonous and dicotyledonous plants. Two efficient detection methods for CMV in orchids, real-time quantitative PCR (RT-qPCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP) were developed in the study. For RT-qPCR, a TaqMan probe-based assay was designed using conserved regions of the coat protein (cp) gene, with a cloned cp plasmid serving as the standard for calibration curve construction. For RT-LAMP, specific inner and outer primers were designed based on the cp gene conserved sequences too. Both methods specificity detection were performed using virus RNA from CMV, Cymbidium mosaic virus (CymMV), and Odontoglossum ringspot virus (ORSV) as templates, and for sensitivity detection was performed using 10-fold serial dilutions of CMV RNA as a template. Additionally, field-collected orchid samples were screened for CMV infection using both techniques. The CMV RT-qPCR and RT-LAMP detection methods established in this study detected only CMV-positive samples without cross-reactivity with CymMV or ORSV. The sensitivity of RT qPCR and RT LAMP was consistent with a dilution of 10⁶ times the original solution. The positive rate of CMV in field orchid samples was 26.7%. The results demonstrate that the RT-qPCR and RT-LAMP established in this study have strong specificity and high sensitivity, and are suitable for monitoring CMV infection in orchids in actual production processes.

Kadsura coccinea (Lem.) A. C. Smith, a traditional medicinal plant widely cultivated in South China, has experienced significant yield and quality reductions due to increasing disease incidence in recent years. This study aimed to identify the causal agent of leaf blight disease in K. coccinea and evaluate fungicide efficacy to establish a scientific foundation for pathogen identification and field management. Pathogens were isolated from symptomatic K. coccinea samples collected in Shaoguan, Guangdong and showing browning and necrosis of leaf and stem tips, using tissue isolation and purification methods. Pathogen was clarified by comprehensive identification combined morphological characterization with multi-locus phylogenetic analysis (ITS, rpb2, LSU and tub2). Pathogenicity was confirmed through Koch's postulates, while the indoor toxicity of seven fungicides to the pathogen was determined via mycelial growth inhibition assays. Isolate SGXFD, obtained from the edges of necrotic leaf tissues, was confirmed as the etiological agent through pathogenicity tests. Polyphasic identification classified the pathogen as Didymella segeticola. Fungicide screening revealed dimetachlone as the most effective inhibitor (EC₅₀=1.8210 mg/L), followed by prochloraz (EC₅₀=3.4460 mg/L) and propiconazole (EC₅₀=3.7391 mg/L). Moderate inhibition was observed with difenoconazole (EC₅₀=11.3202 mg/L), tebuconazole (EC₅₀=45.0019 mg/L), and mancozeb (EC₅₀=51.9597 mg/L). Carbendazim demonstrated limited efficacy (<50% inhibition) across tested concentrations (25.0, 50.0, 100.0, 200.0, 400.0 mg/L). This study establishes D. segeticola as the causative agent of K. coccinea leaf blight. Dimetachlone, prochloraz, and propiconazole exhibit significant antifungal activity against this pathogen, recommending the consideration for field application in disease management programs.

The 3^rd to 5^th instar nymphs and adults were released in tobacco fields and greenhouses to investigate the differences in dispersal capacity and dynamic patterns across developmental stages of Eocanthecona furcellata (Wolff). Under greenhouse conditions, dispersal characteristics including release timing, spatial distribution, diffusion coefficients and colonization rates were analyzed. Additionally, dispersal velocities across different developmental stages were measured under field conditions. Results demonstrated variations in dispersal capacity among developmental stages within 12-48 hours post-release, showing a gradual enhancement trend with advancing insect age. Throughout the release period, adults exhibited significantly higher dispersal coefficients than nymphs in tobacco fields, while in greenhouses, adult dispersal coefficients only surpassed nymphs significantly during 12-24 hours post-release. During dispersal, nymphs in the greenhouse primarily clustered on tobacco plants, while the majority of adults exhibited a radial dispersal tendency. At 72 hours post-release, significant differences in colonization rates emerged among developmental stages in greenhouses, with adults achieving markedly higher rates than nymphs, demonstrating a stepwise decline as instar levels decreased (adult>5^th>4^th>3^rd). Dispersal patterns stabilized with prolonged release duration. This study would provide critical evidence for scientifically evaluating the biocontrol potential of E. furcellata, offering substantial significance for enhancing natural enemy efficacy and advancing scientific pest management strategies.

The study established an ultra-performance liquid chromatography-tandem mass spectrometry technique for the simultaneous determination of six methoxyacrylate fungicides to clarify the possible cumulative dietary intake risk of methoxyacrylate fungicides in fresh mango. The Monte Carlo simulation and relative potency factor methods were employed to assess the cumulative risk of acute and chronic exposure to strobilurin intake from mango consumption in the targeted populations. In 126 mango samples from Hainan, Guangxi and Yunnan, 3 of 6 methoxyacrylate fungicide were detected. The detection rate of pyraclostrobin, azoxystrobinthe and kresoxim-methyl was 31%, 37% and 14% respectively. Picoxystrobin, trifloxystrobin and fluoxastrobin in mango samples were not detected. The ratio of methoxyacrylate fungicide found in a mango sample was 22%. The ratio of 2 and 3 kinds methoxyacrylate fungicides found in a mango sample was 22% and 5%. The most common co-occurrence of methoxyacrylate fungicides was pyraclostrobin and azoxystrobin. The results of dietary risk assessment showed that the risk of residual methoxyacrylate fungicides in mango ranged between 0.1% and 10.2% for acute dietary exposure and between 0.1% and 1.2% for chronic dietary exposure. The exposure was far below the thresholds of dietary risk. The study showed that the cumulative chronic and acute dietary exposure risk of methoxyacrylate fungicide residues in mango are within an acceptable range and do not pose an unacceptable risk to the health of the targeted population.

Tea tree oil (TTO) chitosan emulsion was prepared by ultra-high pressure homogenization method with natural TTO and chitosan as raw materials, Tween-80 as emulsifying agent, and ethanol as co-emulsifying agent. The preparation conditions were optimized by response surface test. The storage stability of TTO chitosan emulsion at different temperatures was investigated, and its antioxidant activity and mildew proof properties were evaluated. The optimal preparation conditions of the emulsion were as follows, the homogenization pressure 160 MPa, the mass fraction of tea tree oil 12%, and the mass fraction of compound emulsifier 4%. Under the conditions, the particle size of the emulsion was 99.24 nm. When stored at 4, 25 and 50 ℃ for 28 days, the particle size remained within 164 nm, the Zeta potential all exceeded 39 mV, and the PDI remained within 0.53, indicating that the storage stability of the emulsion was good. The IC₅₀ value of DPPH radical and OH radical of the emulsion was 22.82 μL/mL and 18.75 μL/mL, respectively, indicating that the emulsion had good antioxidant activity. The mildew proof test showed that the mildew proof ability of bamboo treated with TTO chitosan emulsion was higher than that of untreated bamboo. When the treatment concentration was 80 μL/mL, the antifungal effect was significant.

China is currently the largest sweet potato producer globally. The postharvest starch and soluble sugar (glucose, fructose, and sucrose) contents in storage roots not only influence sweet potato utilization and commercial value (including taste, nutritional quality, and food processing properties), but also affect sprouting, weight loss, and decay during storage and transportation. Studies on tubers/roots such as potato and carrot have demonstrated that vacuolar invertase (VIN) serves as the primary sucrose-cleaving enzyme determining postharvest sugar composition and content. However, the key sucrose-cleaving enzyme regulating postharvest sugar metabolism in sweet potato storage roots remains unclear. This study systematically investigated sugar metabolism characteristics in storage roots of ‘Kokei 14’, a major sweet potato cultivar in Hainan Province, under room temperature storage (25 ℃) and low-temperature storage (15 ℃), aiming to identify the principal sucrose-cleaving enzymes affecting postharvest sugar composition and content. Low-temperature storage enhanced preservation quality by reducing dry matter loss and sprouting rate through suppression of hexokinase (HK) activity and respiratory intensity. Compared with room temperature storage, low-temperature treatment induced greater increases in soluble sugar (glucose, fructose, and sucrose) content and more pronounced starch degradation, accompanied by significantly higher β-amylase activity, indicating that low-temperature storage promotes starch hydrolysis into soluble sugars. During room temperature storage, cell wall invertase (CWIN) and sucrose synthase (Sus) activities generally declined, while VIN activity initially increased before returning to baseline levels. Notably, cytoplasmic invertase (CIN) activity exhibited a continuous upward trend, suggesting CIN as the key sucrose-cleaving enzyme responsible for hexose accumulation under ambient conditions. Conversely, low-temperature storage induced continuous declines in all three invertase activities but progressively increased Sus activity, indicating Sus as the predominant enzyme mediating hexose accumulation under cold storage. Transcriptional analysis identified IbCIN4 as the key gene family members regulating CIN activity elevation at room temperature, while IbSus6 was determined as the primary regulator of Sus activity enhancement under low-temperature conditions. This study reveals that different postharvest storage temperature induces shifts in the predominant sucrose-cleaving enzymes governing hexose accumulation in sweetpotato storage roots. Notably, our findings contrast with previous reports on potato tubers under cold storage, demonstrating that Sus rather than VIN serves as the key enzyme regulating hexose content in sweetpotato roots under low-temperature conditions. The results would establish a theoretical foundation for future genetic engineering approaches to improve postharvest quality of sweetpotato storage roots.

The study was aimed to explore the physiological response and gene expression differences of cassava seedlings under waterlogging stress and to provide theoretical basis for disaster prevention and reduction of cassava northward migration cultivation in Hunan Province. Seedlings of cassava NZ199 were used, and two waterlogging levels of moderate (W1) and severe (W2) were set. The normal water supply (CK) was used as the control. The photosynthetic characteristics and antioxidant enzyme activities of the seedlings were measured after 14 days of stress and after rewatering, and transcriptome sequencing analysis was performed on the leaves after 14 days of stress. The results showed that with the aggravation of stress, the net photosynthetic rate decreased, and the stomatal conductance, intercellular CO₂ concentration and transpiration rate showed an overall upward trend. The activities of superoxide dismutase, catalase and peroxidase were significantly higher than those of CK under waterlogging stress, the content of malondialdehyde increased, and the degree of accumulation was positively correlated with the degree of stress, indicating that the plant initiated the antioxidant mechanism when suffering from waterlogging, but still suffered a certain degree of oxidative damage. After rewatering treatment, the photosynthetic index decreased significantly compared with that before stress. Antioxidant enzyme activity and malondialdehyde content also decreased, indicating that although the plant had a certain recovery ability, it did not fully recover to the normal level before stress. The results of transcriptome sequencing showed that 900, 1542 and 575 differentially expressed genes were identified in the three comparison groups of W1 vs CK, W2 vs CK and W2 vs W1, respectively, of which 1594 were up-regulated and 1423 were down-regulated. The pathways significantly enriched by KEGG included flavonoid biosynthesis, starch and sucrose metabolism, plant hormone signal transduction, etc. In summary, cassava seedlings have certain waterlogging resistance, but the waterlogging resistance has a threshold value. Timely drainage after waterlogging helps to reduce plant damage. In this study, the physiological and gene expression changes of cassava under different degrees of waterlogging stress in Hunan were systematically analyzed, and several differentially expressed genes and pathways related to waterlogging resistance were identified, which would lay a theoretical foundation for screening candidate genes of cassava in response to waterlogging stress, and also provide a new direction for further research on the molecular mechanism of cassava waterlogging resistance and the cultivation of waterlogging resistant varieties.

Sri Lankan cassava mosaic disease, caused by Sri Lankan cassava mosaic virus (SLCMV), is a recently emerging dangerous disease in China. Existing detection methods of SLCMV are constrained by low sensitivity and poor efficiency, impeding related research and applications. Primers and probes were designed according to the gene sequences of the SLCMV, and a positive plasmid standard was prepared. The TaqMan fluorescence quantitative detection technology for SLCMV was established, and its application effect was verified. The method only generated specific fluorescence signals for SLCMV DNA samples, and the minimum detectable amount of the positive plasmid standard was 4.5×10¹ copies/μL. The standard curve showed that there was a good linear relationship between the C_t value and the logarithm of the copy number. The slope of the curve was –3.1312, the correlation coefficient R² was 0.9969, the amplification efficiency (E) was 97.9%, and the equation of the standard curve was y=–3.1312x+34.599. Using this technology to detect the tested samples from two cassava plantations in Guangxi and Fujian, the positive detection rate of leaves was 95.45% and 78.57%, respectively, and the minimum detectable copy number was 1.45×10⁵ copies/g. The virus-carrying rate of Bemisia tabaci in the field was 86%, and the minimum virus-carrying amount was 9.42×10⁴ copies/B. tabaci. This technology has good sensitivity, specificity, and repeatability, and could provide effective technical support for the monitoring and control work such as field identification, early diagnosis, and evaluation of virus-free stem cuttings of the disease.

The MYB family constitutes one of the largest transcription factor families in plants, involving in plant growth and development, signal transduction, and secondary metabolism. Based on our previous 2+3 transcriptome data of Ocimum basilicum var. pilosum, we systematically identified the O. basilicum var. pilosum MYB (ObMYB) family through bioinformatics approaches and explored members associated with essential oil accumulation. Firstly, ObMYB members were screened by homologous alignment of MYB conserved domains, and then their complete open reading frames were predicted and the basic physicochemical properties of these encoded proteins were analyzed. Phylogenetic relationship was reconstructed by neighbor-joining method of MEGA 7.0, while conserved motifs and domains were annotated using MEME and Batch CD-Search. Subsequently, incorporating the previous miRNA data of O. basilicum var. pilosum, the targeted miRNA complementing the ObMYB were predicted by TargetFinder. Lastly, differential expression analysis and visualization analysis of heat maps were conducted by TBtools. Based on the essential oil data from different developmental stages of stems and leaves, the correlation analysis between differential gene expression levels and essential oil content was conducted using SPSS 25 to identify the potential ObMYB members involving in the accumulation of essential oil. The protein-protein interaction (PPI) network was constructed by STRING database for analyzing potential metabolic pathways involved. Research results revealed that a total of 77 ObMYB members were characterized, named as ObMYB-1 to ObMYB-77. Phylogenetic analysis divided them into eight subfamilies (classⅠ-Ⅷ), each comprising 6–14 members. These ObMYB proteins exhibited hydrophilic properties and structural stability, average isoelectric point=7.11 and average hydrophobicity=–0.69. Five miRNAs were found to target and regulate four ObMYB genes. Among these 43 differentially expressed ObMYB genes, ObMYB-4, -9, -27, -34, -42, -46 and -69 displayed strong correlations with essential oil accumulation. Moreover, PPI network analysis indicated the potential involvement of ObMYB-4, -9, -34, -36, -46 and -69 in flavonoid biosynthesis and secondary metabolite regulation. This study systematically identified the ObMYB family members and analyzed their relationship with essential oil accumulation, revealing multiple ObMYB genes significantly associated with the synthesis and accumulation of essential oils. These findings provide a significant theoretical basis for an in-depth understanding of the metabolic regulation mechanisms of O. basilicum var. pilosum essential oil, and to offer new targets and insights for research on plant secondary metabolism and the improvement of aromatic plant quality.

Miniature inverted-repeat transposable elements (MITEs), as active mobile elements in eukaryotic genomes, provide novel molecular markers for germplasm genetic diversity analysis through the insertion polymorphisms. This study systematically identified hAT family MITE transposons in pitaya using bioinformatics approaches based on the whole-genome data of the Guanhua Bai cultivar. A total of 2350 candidate elements with complete terminal inverted repeats (TIRs) and target site duplications (TSDs) were screened, with an average of 213 elements per chromosome pair. Through sequence specificity and polymorphism analysis, 110 highly divergent loci (10 per chromosome pair) were selected for primer design, ultimately yielding 41 stable polymorphic hAT-MITE markers after PCR validation. Genome-wide scanning of 48 pitaya germplasms using the 41 primer pairs detected 81 polymorphic loci (polymorphism rate: 97.59%) via agarose gel electrophoresis. UPGMA cluster analysis revealed substantial genetic variation and diversity among the 48 accessions, with genetic similarity coefficients ranging from 0.57 to 0.91. At a genetic similarity threshold of 0.63, the germplasm resources were categorized into four genetically distinct groups. A digital fingerprinting system covering all germplasm resources was constructed using four core primer pairs (HU-MIT-02/06/26/75) based on the primer-band pattern combination method, achieving 100% cultivar identification accuracy. This study established the first hAT-MITE molecular marker system for pitaya, providing an efficient toolkit including a marker library and standardized identification protocols for precise germplasm classification, cultivar identification and varieties property protection of pitaya. The advancements is of significant application value for intellectual property protection in the pitaya seed industry.