Guizhou Institute of Plant Protection

White leaf spot in maize (WLS) severely threatens maize yield and quality. Risk assessment suggests that it may become one of the most significant maize diseases in China. Exogenous arachidonic acid offers a novel strategy for enhancing crop stress resistance. This study aims to investigate the effects and mechanisms of ARA in inducing resistance against WLS. The study found that 15 µM ARA effectively induces systemic resistance in maize against WLS. This resistance manifests as a multi-layered synergistic defense response. ARA treatment protected the photosynthetic performance of the leaves, primarily by maintaining the photosynthetic area, maximum photochemical efficiency, and photoprotective capacity (NPQ) of the infected leaves, thereby ensuring the supply of energy and carbon skeletons. Additionally, ARA treatment significantly enhanced the phenylalanine metabolic pathway, increasing the activity of key defense enzymes, including phenylalanine ammonia-lyase (PAL), chitinase (CHI), peroxidase (POD), and laccase (LAC). This drove the accumulation of disease resistance-related compounds such as lignin, coumarins, and flavonoids, thereby strengthening both physical and chemical barriers. Furthermore, ARA treatment reduced the accumulation of malondialdehyde (MDA), a product of membrane lipid peroxidation, and reducing sugars, indicating alleviated cellular oxidative damage and improved carbon metabolism balance. Metabolomic analysis further confirmed the critical role of phenylalanine metabolism. This study demonstrates that exogenous ARA application does not merely trigger an isolated response but initiates an integrated disease resistance program, coordinating multiple processes such as photosynthetic protection, cell wall reinforcement, and the accumulation of antimicrobial compounds. Based on the experimental results, we speculate that this systemically enhanced resistance may be closely associated with the activation of the salicylic acid signaling pathway. These findings not only provide a theoretical foundation for utilizing ARA as an eco-friendly plant resistance inducer to control WLS, but also offer novel biological insights into how endogenous signaling networks integrate multiple defense layers, thereby contributing to the advancement of sustainable agriculture. Exogenous arachidonic acid (ARA) induces resistance to white leaf spot in maize (WLS). The most significant effect of ARA at a concentration of 15 µM on WLS resistance. ARA significantly improved the photosynthetic performance of susceptible leaves. ARA significantly increased the activity of relevant defense enzymes in susceptible leaves. ARA may enhance disease resistance by mimicking or potentiating the salicylic acid (SA) signaling pathway.

Advanced genotyping technologies for understanding the genetic intricacies of fungal pathogens have broad applications in crop protection. Here, we introduce a novel genotyping-by-target sequencing (GBTS) chip, a versatile tool designed for comprehensive genetic analysis of fungal populations. This technology overcomes key limitations of traditional molecular marker-based approaches by providing a more efficient, economic, and streamlined solution while bypassing the need for labor-intensive pathogen culturing. We demonstrate its utility by applying it to profile Puccinia striiformis f. sp. tritici (Pst), the causal agent of wheat stripe rust. Our analysis involved 225 infected leaves collected from wheat fields in the northwest oversummering region for Pst in China. We delineated three genetic groups and revealed frequent gene flow, with closer connectivity between Qinghai and Gansu than either province with Ningxia, a pattern consistent with wind trajectory models. These findings illustrate a highly connected regional epidemic system and highlight the value of the GBTS chip for genomic epidemiology. The methodology established here provides a scalable framework for population genetic studies in other fungal pathogens, promising to enhance disease monitoring and management across agricultural systems.

ABSTRACT Pseudomonas syringae pv. actinidiae (Psa) is the causal agent of kiwifruit bacterial canker, but the factors affecting its pathogenicity in natural settings remain poorly explored. In this study, we isolated two Psa strains, G126 and G282, from infected kiwifruit orchards in Guizhou Province of China. Both isolates, categorized as Psa-biovar 3, were confirmed through Psa3-specific primers and phylogenomic analysis. Pathogenicity assays on kiwifruit cultivar “Hongyang” leaves and branches showed significantly reduced numbers of necrotic spots and reduced lesion sizes upon infection with G282 compared to the G1 positive control strain, while G126 showed a nonpathogenic phenotype. Additionally, both strains failed to induce a hypersensitive response in nonhost Nicotiana tabacum plants and exhibited significantly reduced promoter activity of the hrpR/S, hrpL, and hrpA genes, which are crucial for the type III secretion system (T3SS). Genomic sequencing revealed that the T3SS of G126 was defective due to a single-nucleotide polymorphism in the hrpR gene, while G282 was entirely deficient in the type VI secretion system (T6SS), which potentially regulates the expression of T3SS genes. Transcriptomic analysis showed widespread alterations in key aspects of the secretion system, protein transport, and signal transduction, further supporting the phenotype characteristics exhibited by the strains. This study enhances our understanding of the genetic basis of nonpathogenic and partially pathogenic Psa isolates, highlighting the functional interdependencies between T3SS and T6SS.

ObjectivesTo evaluate the effect of lateral versus supine positioning on incidence of hypoxaemia in sedated patients and to provide evidence based recommendations for respiratory strategies.DesignProspective, multicentre, randomised controlled trial.Setting14 tertiary hospitals in China, July to November 2024.Participants2159 adults (≥18 years) who underwent sedation.InterventionsSedated patients were randomly assigned (1:1) to receive either lateral positioning or conventional supine positioning, stratified by study centres.Main outcome measuresThe primary outcome was incidence of hypoxaemia (peripheral oxygen saturation (SpO2) ≤90%) within the first 10 minutes after positioning. Secondary outcomes included airway rescue interventions, incidence of severe hypoxaemia (SpO2 ≤85%), lowest oxygen saturation recorded, length of stay in the post-anaesthesia care unit, and safety measures (eg, bradycardia, tachycardia, hypotension, new onset arrhythmia). Analyses were performed on an intention-to-treat basis.ResultsOf 2159 patients randomised, 2143 were included in the primary analysis. The mean age of the patients was 53.1 years, mean body mass index was 23.9, and 53.7% (1150/2143) were women. The incidence of hypoxaemia was significantly lower in the lateral group compared with supine group (5.4% (58/1073) v 15.0% (161/1070); adjusted risk ratio 0.36, 95% confidence interval (CI) 0.27 to 0.49; P<0.001). Compared with patients in the supine group, patients in the lateral group required fewer airway rescue interventions (6.3% (68/1073) v 13.8% (148/1070); adjusted risk ratio 0.46, 0.34 to 0.61; P<0.001), had a lower incidence of severe hypoxaemia (0.7% (8/1073) v 4.8% (51/1070); adjusted risk ratio 0.16, 0.07 to 0.33; P<0.001), and had a higher mean lowest SpO2 level (96.9% v 95.7%, absolute adjusted mean difference 1.20%, 95% CI 0.87% to 1.54%; P<0.001). Additionally, length of stay in the post-anaesthesia care unit was shorter in the lateral group (38.2 v 40.5 minutes; absolute adjusted mean difference −2.22 minutes; 95% CI −3.63 to −0.80; P=0.002). Safety outcomes were comparable between the groups, but tachycardia was less frequent in the lateral group.ConclusionsPlacing sedated adults in the lateral position significantly reduces the incidence and severity of hypoxaemia and decreases the need for airway rescue interventions without compromising safety. Given its simplicity and low cost, lateral positioning could offer advantages in remote or resource constrained clinical settings. Further replication studies targeting patients with advanced age and high body mass index are needed to improve the generalisability of the findings.Trial registrationClinicalTrials.gov NCT06459167.

Identifying surface defects in metal manufacturing is essential due to their significant impact on product quality and production efficiency. Despite advancements in Vision Transformers (ViTs), challenges remain with the variability and imbalance of defect samples. This study proposes RFA Convolution -CBM-ViT, a novel Vision-oriented Transformer network combining Responsive region Attention Convolution (RFA Convolution) and Content Balancing Middle value(CBM). The integration of RFA Conv in the Patch Embedding stage optimizes the coverage of the perceptive region, improving the model's capability to retrieve global features and address defects across varying scales effectively. This approach improves accuracy and convergence speed without adding computational overhead. Additionally, the CBM method employs centralized tokens in the feedforward perceptron intended to simplify attention map compactness, minimizing noise and non-essential features significantly improves the model's precision without adding computational burden. Tests confirm that the RFA Convolution-CBM-ViT model delivers top-tier results on various publicly available metal surface defect datasets, underscoring its promising application in the metal manufacturing sector.

Mythimna separata larvae exhibit both solitary and gregarious phases under low and high population density, respectively; furthermore, differences in morphology, behavior and physiology have been observed in the two phases. The integument plays an essential role in the fitness, general metabolism, communication, and survival of insects; however, differences in the integument ultrastructure and gene expression in the solitary and gregarious phases are largely unknown. In this study, the integument ultrastructure of larvae in the solitary and gregarious phases was compared, and transcriptome analysis was conducted to identify which genes were differentially expressed in the two phases. The results showed that the gregarious larvae had thicker integuments and more polygonal particles on the cuticle surface than solitary larvae. Using the Illumina HiSeq™ sequencing platform, 2774 differentially expressed genes (DEGs) were generated. Among these, many transcripts were identified with roles in the synthesis of fatty acids; structural components of the integument and the insecticide detoxification were differentially expressed in the integument of the two larval phases. qRT-PCR was used to validate expression patterns of the selected transcripts. This study provides a valuable resource for understanding the molecular basis of behavioral and physiological differences in the two phases of M. separata.

Juvenile hormone (JH) regulates multiple physiological functions in insects including growth, metamorphosis, and reproduction. Juvenile hormone epoxide hydrolase (JHEH) and juvenile hormone esterase (JHE) are degradative enzymes that metabolise JH, and JH receptor (methoprene-tolerant, Met) functions in the regulation of female reproduction and vitellogenesis. In this study, JH titres in Coccinella septempunctata adult females were determined using ultra high-performance liquid chromatography and tandem mass spectrometry; the JH titres ranged from 0.03 to 0.16 ng g-1 in 5- to 30-day-old female adults. JHEH, JHE, and Met expression were studied in different reproductive stages of C. septempunctata females by quantitative real-time PCR. JHEH transcription levels were highest in 25-day-old female adults and were 1.93-fold higher than expression levels in 5-day-old adults. JHEH and JHE expression levels were inhibited by the addition of JH to the artificial diet. Met expression in C. septempunctata supplied with 3 μl JH in artificial diet was similar to Met transcription in females supplied with an aphid diet, and the results showed that supplementation with 3 μl JH in 582.2 g of artificial diet was the most suitable for reproductive regulation of C. septempunctata. The results of this study provide important insights for the improvement of C. septempunctata artificial diets.