To investigate the differences in response and labeling efficiency of C₃ and C₄ crops to carbon isotope pulse labeling, this experiment selected C₃ crops (rice and peanut) and C₄ crops (maize and sugarcane) as research subjects. A total of five rounds of ¹³C pulse labeling were conducted in pot experiments to analyze the ¹³C enrichment abundance, fixation amount, and labeling efficiency of the crops, aiming to reveal the differences in carbon fixation and pulse labeling efficiency between C₃ and C₄ crops. The results showed that under labeling treatment, the δ¹³C values and isotope abundance F values of C₃ and C₄ crops showed significant differences, following a consistent pattern: C₃ crops>C₄ crops. The δ¹³C values of the four crop types were as follows: rice (396.90‰-410.05‰)>peanut (269.51‰-364.66‰)>maize (148.15‰-182.47‰)>sugarcane (152.50‰-153.91‰). Under non-labeled treatment, δ¹³C values were as follows: sugarcane (-15.63‰ to -15.16‰)>maize (-18.25‰ to -16.52‰)>rice (-34.53‰ to -33.82‰)=peanut (-35.41‰ to-33.37‰). The ¹³C fixation amount and labeling efficiency showed consistent trends, with no significant differences between C₃ and C₄ crops. Among the four crops, peanut and sugarcane treatments were significantly higher than rice and maize, and peanut was significantly higher than rice. Peanut had the highest labeling efficiency at 46.02%, followed by sugarcane at 33.27%, and rice had the lowest at 24.55%. This study reveals the response differences of C₃ and C₄ crops to ¹³C pulse labeling and provides important data support for the application of stable isotope techniques in crop carbon labeling.

Rubber tree anthracnose is one of the two major foliar diseases of rubber trees, ranking second in severity only to powdery mildew. It has caused significant economic losses to rubber latex production during rubber tree cultivation in China. Against this backdrop, this study focuses on the pathogen of rubber tree anthracnose, investigating its fundamental biological characteristics, molecular identification, antifungal spectrum determination of biocontrol agents, and green prevention strategies. The research begins with a survey of anthracnose incidence in major rubber tree cultivation areas of Hainan province, collecting diseased leaves from rubber forests in Qionghai, Baoting and Chengmai. Pathogenic fungi were isolated and purified, followed by molecular identification and antifungal spectrum analysis by biocontrol agents. Finally, a strain (HZS-BT) isolated from Baoting was subjected to fundamental biological characteristic studies. The findings reveal that, through field surveys of rubber tree anthracnose in various regions of Hainan, it was observed that currently predominant rubber tree varieties in Hainan, such as RY73397, PR107 and RRIM600, exhibit poor resistance to anthracnose under current climatic and ecological conditions. By amplifying core genes, multiplex gene sequencing, and specific primer detection, followed by BLAST comparison with genome sequences of standard strains in the NCBI database, the anthracnose pathogen strain HZS-BT isolated from Baoting was identified as Colletotrichum siamense. The optimal growth temperature for the tested anthracnose strain is 28 ℃, with a preferred pH of 8.0, though the strain demonstrates a broad pH adaptability range. The most suitable carbon and nitrogen sources for its growth are sorbitol and beef extract, respectively. Antifungal spectrum analysis indicates that all 11 biocontrol strains possess potential for biological control applications against anthracnose. This study provides a theoretical foundation for the green prevention of rubber tree anthracnose.

Tetranychus urticae is a significant pest on cassava. Long-term use of abamectin has led to prominent resistance issues. Selecting mite-resistant cassava varieties represents a green, effective and straightforward approach to pest control. However, the effectiveness of resistant cassava varieties against resistant mite strains remains unclear, limiting its utility in supporting resistance management decisions. Accordingly, this study used mite-resistant cassava cultivar C1115, mite-susceptible cassava cultivar SC205 and the preferred host plant cowpea as test materials to investigate the effects on the development, reproduction and detoxification metabolism capabilities of abamectin-resistant (AB-R) and abamectin-sensitive (AB-S) strains. Results showed that compared to feeding on cowpea, feeding on SC205 did not significantly alter the developmental duration or population growth parameters [net reproductive rate (R₀), intrinsic rate of increase (r_m), mean generation time (T), population doubling time (DT)] of either AB-R or AB-S strains. In contrast, feeding on C1115 significantly prolonged the developmental duration and inhibited population growth (significantly decreased R₀ and r_m, significantly increased T and DT) of both strains. Furthermore, on C1115, the T and DT of the AB-R strain were also significantly lower than those of the AB-S strain. Regarding detoxification enzyme activities, compared to feeding on cowpea, feeding on both SC205 and C1115 significantly increased the activities of three detoxification enzymes-cytochrome P450 monooxygenases (P450s), glutathione S-transferases (GSTs) and uridine diphosphate-glycosyltransferases (UGTs) - in both mite strains. Enzyme activities were significantly higher in mites feeding on C1115 compared to those on SC205. Additionally, on all three host plants, the enzyme activities of the AB-R strain were consistently significantly higher than those of the AB-S strain. Detoxification genes associated with abamectin resistance exhibited different expression patterns. Although feeding on both C1115 and SC205 significantly upregulated the expression of six tested genes in both mite strains compared to feeding on cowpea, differences emerged when comparing strains on the same cassava variety. When AB-R and AB-S fed on the same cassava cultivar (C1115 or SC205), the expression levels of CYP389C10, UGT201D3 and UGT11 showed no significant difference. However, the expression of CYP392A16, GSTd01 and GSTm09 was significantly higher in the AB-R strain than in the AB-S strain. The results indicate that the AB-R strain of T. urticae, likely due to its enhanced detoxification capacity, might possess an advantage in neutralizing toxic secondary metabolites from the mite-resistant cassava, potentially compromising the pest control efficacy of this resistant cultivar. This hypothesis, however, requires further validation through subsequent field experiments. This study provides a preliminary theoretical basis for evaluating the application potential of mite-resistant cassava in the management of mite resistance to acaricides.

To address mango leaf disease recognition in complex in-field scenes, where background interference and simultaneous infections across multiple leaves lead to feature recognition difficulties and multi-task segmentation problems, this paper proposes G-Mask2Former, a structure-space-guided model that achieves collaborative segmentation of leaf instances and lesion semantics. The method jointly learns leaf and lesion segmentation within a shared feature space, and leverages a leaf-structure prior to impose spatial constraints on the lesion predictions. First, based on Mask2Former, we use multi-scale pixel representations and mask attention to extract effective features of mango leaf diseases in complex scenes; by constructing pseudo-instances of lesions, we achieve leaf instance segmentation and lesion semantic segmentation within a single model, thereby simplifying model deployment and inference. Second, through a leaf structure-space soft gating module, the model is guided to focus on leaf regions, reducing interference from complex environments. Finally, we conduct experiments on a mango leaf disease dataset collected in complex in-field scenes and perform comparative analyses against other models. The proposed method achieves superior overall performance over classical baselines for segmenting mango leaves and diseases in complex in-field scenes. On the test set, the average precision (AP) for leaf instance segmentation reaches 87.37%, while the mean Intersection-over-Union (mIoU) for lesion semantic segmentation reaches 82.83%. The proposed method would provide an effective solution for mango leaf disease segmentation in complex environments and facilitates quantitative disease assessment.

The study was aimed to screen actinomycetes with good control effects on sugarcane red rot and enrich the resources of biocontrol bacteria for sugarcane red rot. JY53, WK29 and JR28 were screened from sugarcane rhizosphere soil, which showed superior antifungal effects against sugarcane red rot pathogen. They were identified as Streptomyces virginiae, S. iranensis and S. lavendulae, respectively. The antifungal rate of WK29 against six plant pathogens ranged from 68.41% to 78.22%. The antifungal rate of JY53 against five pathogens ranged from 58.66% to 72.85%. The inhibition rates of four plant pathogens by JR28 ranged from 27.69% to 60.15%. All the strains exhibited a certain broad-spectrum activity. Further exploration of the antifungal mechanism revealed that JY53 inhibited pathogen growth by producing β-glucanase, siderophore and volatile substances, while WK29 and JR28 inhibited pathogen growth by producing protease, β-glucanase, cellulase, siderophore and volatile substances. Pot experiment showed that after treatment with the bacterial solution of JY53, WK29 and JR28, the incidence indice of sugarcane red rot was 28.00, 25.33 and 22.67, respectively, significantly lower than 64.00 of the CK, and had a good growth promoting effect. This study indicates that actinomycetes JY53, WK29 and JR28, have certain effects on the prevention and control of sugarcane red rot disease, further enriching the resources of biocontrol bacteria for sugarcane red rot disease.

The inoculation of biocontrol fungi may affect the community structure of microorganisms in the soil, and changes in soil microbial community structure may in turn affect the control effectiveness. This study focused on the most harmful invasive pest, the red imported fire ant Solenopsis invicta Buren. The highly pathogenic Beauveria bassiana strain HHY-B was applied to its nest to reveal the impact of pathogen infection on the nest microbial community structure of the red imported fire ant. The microbiome analysis was conducted on soil samples of B. bassiana infected ant nests after 48 and 96 hours, as well as uninfected ant nests using high-throughput sequencing technology. A total of 648 708 valid bacterial sequences were obtained, belonging to 38 phylum, 127 classes, 274 orders, 451 families and 897 genus. 898 443 fungal sequences were also obtained, belonging to 12 phylum, 38 classes, 88 orders, 197 families, 377 genus. The Proteobacteria and Actinobacteria dominated the soil bacterial community in ant nests. Treatment with B. bassiana significantly increased the relative abundance of Proteobacteria in ant nests (P<0.05), but had no significant effect on the relative abundance of Actinobacteria. Ascomycota dominated the fungal community in the nest soil, and its relative abundance treated with B. bassiana was significantly increased in ant nests (P<0.05). In terms of relative abundance at the genus level, the genus of Beauveria showed an dominate fungi in the two treatment groups, which was not found in the control group. The KEGG pathway analysis showed that the differential bacteria were mainly focused on metabolic pathways, biosynthesis of secondary metabolites, microbial metabolism in various environments, biosynthesis of amino acids, carbon metabolism, two-component systems, ribosomes and other metabolic pathways. The enrichment level of the pathways in the control group was higher than that in the treatment group. This study revealed the changes in the microbial community structure of the red imported fire ant nests after treatment with B. bassiana, which helps to the further understanding of the mechanism of B. bassiana on the red imported fire ants and the living environment, and provides theoretical basis for the biological control for the red imported fire ants.

This study investigated the quality variation and climatic adaptation mechanisms of Hainan large-leaf and Yunnan large-leaf black tea through multi-component analysis and aroma characterization of tea samples from Wuzhishan, Wanning, and Baisha. The results demonstrated that Hainan large-leaf tea exhibited superior photosynthetic performance in Wanning and Wuzhishan, with maximum net photosynthetic rate reaching 7.28 μmol/(m²·s), accompanied by high amino acid content (up to 93.50 μmol/g) and moderate caffeine levels (3.93%-4.31%), forming a distinctive "high amino acid-moderate astringency" flavor profile. Aroma component analysis revealed significant regional differences in Hainan large-leaf tea, with Wanning characterized by benzaldehyde (14.51%)-dominant fruity notes and Baisha featuring linalool (31.18%)-rich floral aroma. Climatic adaptability analysis indicated that higher temperatures in Wanning (annual average 24.40 ℃) promoted the synthesis of tea polyphenols and catechins, while the cooler climate of Baisha (annual average 22.30 ℃) was more conducive to theaflavins formation and aroma compound accumulation. Compared with Yunnan large-leaf tea, Hainan large-leaf tea showed significant advantages in photosynthetic efficiency, amino acid accumulation, and aroma composition. The findings would provide theoretical support for optimizing production regions and developing characteristic products of Hainan black tea, with important implications for enhancing its market competitiveness.

This study systematically analyzed the nutritional composition, active ingredient content, and antioxidant activity of Camellia oleifera Abel. seed cake (COSC) from Yunnan and Jiangxi provinces. The results revealed significant differences in nutritional composition between the two regional samples. COSC from Jiangxi exhibited higher moisture (8.57%), ash (12.31%), and total dietary fiber content (62.73 g/100 g), whereas the Yunnan sample possessed higher levels of crude fat (11.47%), crude protein (12.14%), and total amino acids (0.99 g/100 g). Both samples were rich in beneficial compounds, including vitamin E, vitamin K₃, oleic acid, and linolenic acid. The Yunnan sample contained higher levels of mineral elements such as phosphorus, sulfur, and potassium. Regarding bioactive compounds, Jiangxi COSC showed higher total phenolic (3.29 μg/mg) and total flavonoid (66.75 μg/mg) content, while Yunnan COSC exhibited higher polysaccharide (48.32 μg/mg) and tea saponin (222.10 μg/mg) content. Antioxidant activity analysis indicated that Jiangxi COSC demonstrated stronger DPPH radical scavenging capacity and ferric reducing antioxidant power (FRAP), whereas Yunnan COSC showed superior ABTS cation radical scavenging activity. In summary, Yunnan COSC is suitable for developing high-protein supplements, while Jiangxi COSC is more appropriate for high-fiber feed applications. Both samples exhibited promising antioxidant activity, indicating potential for functional product development. This study would provide a theoretical foundation for the resource utilization and value-added applications of C. oleifera seed cake.

Internode length is a key factor determining sugarcane plant height, and appropriate promotion of sugarcane internode elongation can increase unit yield. The gibberellin insensitive dwarf (GID) gene is a core receptor in the gibberellin (GA) signaling pathway. Previous studies have shown that sugarcane GID1 is highly expressed during the vigorous internode elongation stage, and its overexpression can enhance GA signaling to promote internode elongation. In this study, using the sugarcane variety Guitang 42, Xintaitang 22, Guifu 98-296 as the material, the coding sequence (CDS) of ScGID2 (gibberellin receptor protein) was cloned and subjected to bioinformatics analysis. Besides, quantitative real-time PCR (qRT-PCR) was used to analyze the expression patterns of the gene in different tissues, different genotypic varieties, and under gibberellin (GA₃) treatment. Result showed that the cloned ScGID2 gene had a full-length CDS of 720 bp, encoding 239 amino acids, containing a conserved F-box domain. It shared high homology (>88.75%) with GID2 from gramineous plants such as sorghum and maize, and was mainly localized in the nucleus. Expression pattern analysis revealed that ScGID2 had the highest expression level in the shoot apex at the non-elongation stage, followed by the +2 internode at the vigorous elongation stage. There were differences in the expression patterns of ScGID2 among different sugarcane varieties. The expression of ScGID2 in Xintaitang 22, Guifu 98-296, and Guitang 43 showed a trend of first increasing, then decreasing, then increasing again, and then decreasing again. The expression level of ScGID2 in Guitang 43 was much higher than that in Xintaitang 22 and Guifu 98-296. The expression level of ScGID2 in Guitang 42 increased gradually, reaching the peak at 30 days. The expression peak of ScGID2 in long-internode varieties was significantly higher than that in short-internode varieties and lasted longer. After GA₃ treatment, the expression peak of ScGID2 in the short-internode variety Guitang 14-818 appeared earlier than that in the long-internode variety Guifu 98-296. Taken together, the present study provides a theoretical basis for elucidating the molecular mechanism of gibberellin-mediated sugarcane internode elongation, and ScGID2 could serve as a potential molecular target for sugarcane plant height improvement, since the expression of ScGID2 is induced by gibberellin and positively correlated with the internode elongation rate.