Mango (Mangifera indica L.) is an important tropical fruit in Hainan province. Ethylene plays a vital role in the ripening process of mango. ERF transcription factors are key downstream components of the ethylene signaling pathway, and as one of the largest families of transcription factors, they play a role in regulating signal transduction and physiological responses. To investigate the impact of ERF transcription factors on the coloration of postharvest mango peels, this study focused on the Guifei mango as the research subject. Through PCR cloning, the MiERF3 gene was obtained, and bioinformatics methods were used to analyze its basic physicochemical characteristics, conserved domains, protein structure, and evolutionary relationships. Real-time quantitative PCR (qRT-PCR) technology was then employed to analyze the specific expression of the MiERF3 gene in different tissues of mango and during postharvest storage periods. The results indicated that MiERF3 was 717 bp in length, encoding 238 amino acids. The protein had a molecular formula of C₁₁₃₀H₁₇₆₃N₃₃₉O₃₅₅S₉, a molecular weight of 26.066 kDa, and a theoretical isoelectric point of 8.62, with 30 positively charged residues and 27 negatively charged residues. The protein exhibited hydrophilic properties and a structurally unstable nature. MiERF3 protein had no a signal peptide and transmembrane region, with threonine being the primary site for phosphorylation modification. It contained an AP2 conserved domain, and its secondary structure was primarily composed of 61.67% random curl, along with 27.75% α-helix, 3.96% β-fold, and 6.61% extended chain. The three-dimensional structural model of MiERF3 contained three β-fold and one α-helix, consistent with the characteristics of the AP2 structural domain. Multi-sequence alignment and motif analysis suggested that MiERF3 belonged to the ERF subfamily. Based on phylogenetic analysis, the protein most closely related to MiERF3 was PvERF3-like from Pistacia vera, a plant belonging to the same family as mango. Onion subcellular localization and transcriptional self-activation assays showed that MiERF3 was localized in the nucleus and had transcriptional self-activating activity. Quantitative real-time fluorescence analysis showed that the expression of MiERF3 varied among different mango tissues, with the highest expression observed in the sunny side peel of mango fruit. During storage, the expression of MiERF3 showed a clear trend of initial increase followed by decrease, suspecting that MiERF3 may play a positive regulatory role in the process of fruit ripening and color change. This study would provide a theoretical basis for revealing the regulatory role of ERF transcription factors in postharvest ripening and senescence of mango.

The study was aimed to explore the resistance to Colletotrichum siamense, dominant specie of rubber tree induced by Burkholderia arboris DHR18. The enzyme activity changes on the treatments of different concentrations of DHR18 fermentation broth and co-treatments of DHR18 with C. siamense CH-1 using rubber clone GT1 were studied. Five defensive enzymes including catalase (CAT), peroxidase (POD), phenylalanin ammonialyase (PAL), and superoxide dismutase (SOD) were assayed. Results indicated that treatments with 1×10⁸ CFU/mL, 1×10⁷ CFU/mL, 1×10⁶ CFU/mL of DHR18 fermentation broth showed significant higher activities of CAT, POD, PAL, SOD and PPO in rubber leaves compared to the control group. The enzyme activities with broth concentration 1×10⁷ CFU/mL were the highest. The activity peak of the five enzymes was 1 009.14, 29 138.67, 110.24, 902.42 and 148.00 U/g, respectively, which was 2.68, 3.35, 1.88, 3.97 and 4.51 times of the control group, respectively. Under the co-treatments of B. arboris DHR18 and C. siamense CH-1, treatment group inoculated with DHR18 fermentation broth before inoculated with CH-1, the enzyme activities were higher than other co-treatment groups, and significantly higher than that of the control group. Activity peak of CAT, POD, PAL, SOD and PPO was 1 230.85, 45 504.67, 117.53, 1 342.17 and 134.40 U/g, respectively. They were 4.56, 3.10, 2.04, 3.28 and 5.98 times that of the control group, respectively; The plate inhibition rate of strain DHR18 against C. siamense was 71.56%, the preventive effect against C. siamense on rubber saplings was 81.79%, and the control effect was 44.35%. The results showed that Burkholderia arboris DHR18 could promote the activity of defense-related enzymes in rubber trees and induce systemic resistance in rubber trees. The induced resistance may be one of the reasons for the control of C. siamense by B. arboris DHR18.

Hainan is the main producing area of noni in China. Short-term waterlogging stress is caused by typhoons occuring frequently in summer. However, there are few studies on the physiological response of noni to short-term waterlogging stress and after stress relief, and the effect of stress on yield is still unclear. In this study, Noni seedlings growing for 6 months were used as the experimental materials, and short-term waterlogging stress was simulated by potted continuous immersion for 15 days. Dry weight, net photosynthetic rate (P_n), proline (Pro) content of leaves, root activity (TTC), root malondialdehyde (MDA), peroxidase (POD) and superoxide dismutase (SOD) were measured at 1st, 3rd, 7th, 10th and 15th days after waterlogging. The relevant indexes were measured on the 1st, 7th and 15th day after stress relief, and the yield of waterlogged and non-waterlogged plots in the main producing areas was measured for 3 consecutive years. The results showed that the physiological response of Noni after waterlogging stress was rapid. Compared with non-waterlogging control treatment, the net photosynthetic rate of leaves decreased on the 1st day of waterlogging, the content of Pro increased, the content of MDA in roots increased, the root activity decreased, and the activities of antioxidant enzymes such as POD and SOD increased. All the indexes changed significantly in the first 7 days. However, after 7 days, the changes of TTC and SOD activity of roots remained significant, but the changes of other indexes were slow, indicating that leaves and roots gradually adopted corresponding strategies to adapt to waterlogging stress. The biomass root shoot ratio of Noni remained unchanged at the initial stage of waterlogging, but decreased significantly after 3 days, which also reflected that Noni plants had responded to waterlogging stress in a short period of time. After the stress was relieved, the physiological processes gradually recovered, and at 15 days, Noni photosynthesis and root activity basically recovered, but the content of peroxides such as MDA was still significantly higher than that of the control, indicating that the toxic effect of peroxides formed under early stress was difficult to eliminate in the short term. The multi-year yield of main producing areas shows that short-term but frequent waterlogging stress can lead to a significant decrease in yield, which is 21.64%–35.21%, which may be related to peroxide toxicity caused by stress. In summary, short-term waterlogging stress not only has a great impact on the physiological process of noni during stress, but also its adverse effects persisted for a long time after the stress is lifted, thereby affecting crop growth and yield. Therefore, for planting noni, the plots with higher terrain and better drainage should be in priority. In water-prone planting areas, water should be drained within 72 hours to minimize the adverse impact.

Cytoplasmic invertase (CIN) irreversibly hydrolyzes sucrose into glucose and fructose and plays an important role in the development of roots in various model plants. Presently, there is no research on the CIN gene family in sweetpotato (Ipomoea batatas) and the role of IbCINs in the development of storage roots of sweetpotato remains to be elucidated. This study systematically identified the types and quantities of IbCIN gene family. Physicochemical properties, chromosome localization, phylogeny, gene structure and conserved motifs, promoter cis elements of IbCINs were also analyzed. Simultaneously, through the expression analysis of IbCINs in different tissues and different types of roots, and the activity analysis of CIN in different types of roots, several candidate CIN genes were identified that play an important role in the development of storage roots of sweetpotato. A total of 12 IbCIN genes (IbCIN1-12) were identified from the genome of sweetpotato, distributing on 8 chromosomes. The number of amino acids of IbCIN-encoded protein was 417-825 aa, the molecular weightwas 46.60-93.75 kDa, and the isoelectric point was 4.83-7.17. Phylogenetic analysis revealed that IbCINs could be divided into three groups, α1, α2 and β groups, comprising 1, 3 and 8 members, respectively. α1 and α2 members were very conservative in conserved motifs and gene structures, while β memberswere less conservative, which indicating that β group may have more diverse function than the other two groups, allowing β members to participate in more biological processes. In addition, phylogenetic analysis also revealed that IbCIN1, IbCIN7, IbCIN10 and IbCIN12 were closely related to CIN genes related to root development in Arabidopsis and cassava, suggesting that the four genes may play important roles in the development of non-storage root of sweetpotato. The analysis of the expression levels of IbCINs in different tissue (young leaves, mature leaves, stems, flowers, 60 d storage roots) and different types of roots (white fiber roots, red fiber roots, pencil roots and 60 d storage roots) showed that IbCIN4, IbCIN8 and IbCIN11 had the highest expression levels in storage roots, and simultaneously the CIN activity in storage roots was significantly higher than that in non-storage roots. Thus, it can be speculated that the three genes may play an important role in the development of storage roots of sweetpotato. Bioinformatics analysis further revealed that IbCIN4, IbCIN8 and IbCIN11 may jointly promote the development of storage roots via different mechanisms, including facilitating sucrose transport to and subsequent degradation in storage roots, attenuating photoperiod response and signal transduction of gibberellin. This study could lay a foundation for further research on the function of IbCIN genes through transgenic technology.

The accurate identification of sugarcane stem nodes is of significant value for intelligent seed cutting, planting positioning, optimizing the production management process of sugarcane gardens, and improving yields and economic benefits. However, existing sugarcane stem node detection methods still have shortcomings in terms of performance, model complexity, and real-time performance. In order to effectively solve this problem, this study chose to use the advanced YOLOv8 model to visually detect sugarcane stem nodes in a structured scene. First, a field sugarcane image collection experiment was designed, the collected sugarcane images were manually labeled, and an image training set and a test set were established. Then, the YOLOv8 network was used as the sugarcane stem node detection model to determine the optimal hyperparameter combination and conduct model training. Finally, actual recognition experiments in the field are conducted to verify the effectiveness and efficiency of this method. Experimental results show that the precision, recall, mAP, single-frame inference time and model size of our method on the test set are 0.973, 0.958, 0.974,19.80 ms and 6.30 MB respectively. Compared with the Edgeyolo_S_Coco network and Edgeyolo_Tiny network, the mAP value of the YOLOv8_n network has increased by 1.70% and 1.30% respectively, the single-frame inference time has been reduced by 4.71 ms and 1.50 ms respectively, and the model size has been reduced by 33.70 MB and 17.50 MB respectively. This method has advantages in detection performance and generalization ability, and can effectively meet the requirements for algorithm accuracy and model complexity in outdoor environments, providing solid technical support for sugarcane harvesting and planting in intelligent agricultural production.

Sisal hybrid variety of H.11648 is the main cultivated commercial variety in China. Despite of its ability to produce high fibre yield per unit area, this variety is highly susceptible to diseases. Sisal zebra disease, caused by Phytophthora nicotianae is among the diseases of economic importance affecting the variety. Several control measures like the adoption of good agricultural practices, the use of disease resistant variety and the use of chemical control are suggested in sisal zebra disease control. However, none of them seem to be sustainable due to the existing agricultural practices. Most of the existing measures are not only time-consuming but also costly due to labor intensification and high cost of purchasing agricultural chemicals which on another hand can pollute the environment and create resistance to the plants. Developing resistance variety will obviously take long time due to the long life cycle of sisal. It is very important to develop sustainable disease control methods which are environmental friendly to adopt the climate change agenda. The use of microorganisms to control the diseases is of great importance. In this study, an antagonistic strain PaHNHK01 was successfully isolated by using Phytophthora nicotianae as the target pathogen. PaHNHK01 was identified as Pseudomonas aeruginosa based on morphological, physiological and biochemical characteristics and gene sequence analysis. The antibacterial activity and control effect of PaHNHK01 were measured under in vitro condition. The results showed that, PaHNHK01 had the ability of organophosphorus and inorganic phosphorus, nitrogen fixation and iron production. Additionally, PAHNHK01 had the inhibition rate of 89.79% against P. nicotianae. The fungus effectively inhibited the mycelial growth of P. nicotianae, and the antagonistic pathogens showed decreased sporulation ability, mycelial enlargement deformity and increased branching. The control effect of PaHNHK01 on sisal zebra disease in vitro was 88.62%. PaHNHK01 aseptic fermentation liquid had obvious bacteriostatic effect on pathogenic bacteria, and its EC₅₀ value was 20.3679 μL/mL. When the concentration of PaHNHK01 crude extract was 80 μg/mL, the antibacterial rate was 89.36%, and the EC₅₀ value of PaHNHK01 crude extract was 11.9456 μg/mL. We further observed the antagonistic effects of the strain PaHNHK01 on 13 different plant pathogens, indicating that the strain PaHNHK01 had good biocontrol potential and could be developed as a biocontrol product. The results would provide a strong research basis for the biological control of sisal zebra disease.

The pathogen of pitaya stem rot in Guangxi was isolated by the tissue separation method and the microbial control of the disease was selected. According to Koch’s rule, the pathogenicity was verified by in vitro experiments, and the pathogenic species were identified by the morphological and multi-gene sequence analysis. Then, the biocontrol bacteria were screened by the plate confrontation method. The results showed that two pathogenic fungi, Lasiodiplodia pseudotheobromae and Neoscytalidium dimidiatum, were isolated from the decayed stems of pitaya, of which L. pseudotheobromae was the first reported to cause pitaya stem rot in China. Taking L. pseudotheobromae PY6 as the target pathogen, Bacillus subtilis L3-4 with the best control effect was obtained from 34 strains of pitaya endophytes screened, which could make the mycelium of PY6 entangled and broken. The sterile fermentation filtrate and the sterile fermentation broth after 100 ℃ treatment had antibacterial effect, and the prevention effect could reach 72.08% and 71.16%, respectively. But it did not produce volatile compounds that inhibited the growth of PY6 strain. In addition, strain L3-4 exhibited inhibition to Botryosphaeria dothidea, Fusarium pseudograminearum, F. oxysporum and N. dimidiatum with inhibition rate 77.65%, 73.13%, 64.07% and 62.01%, respectively. This study clarified the pathogenic pathogen responsible for pitaya stem rot in Guangxi. The screened biocontrol bacteria could be used as candidate strain for controlling pitaya stem rot. The result would provide a theoretical basis for diagnosing and biologically controlling pitaya stem rot.

The pericarp color, browning-related enzyme activity and variations in phenolic compounds during the browning process of litchi pericarp were evaluated to investigate the alterations in ingredients caused by pericarp browning of two litchi varieties (Guiwei and Yuhebao) during storage. The indicators were comprehensively evaluated using correlation analysis and principal component analysis. The results showed that at a storage temperature of 4 ℃, the pericarp of Yuhebao was more likely to brown than that of Guiwei. After being stored for three days, the pericarp of Yuhebao exhibited noticeable browning, but Guiwei only displayed a similar phenomenon after seven days of storage. Over the period of 0-14 days of storage, both Guiwei and Yuhebao showed a decline in the total phenolic, flavonoid and proanthocyanidin levels in the pericarps due to browning. Both Guiwei and Yuhebao pericarps exhibited an increased trend in pH value, with the lower rise rate in pH value of Guiwei pericarp compared with that of Yuhebao. Additionally, the level of polyphenol oxidase (PPO) activity in the pericarps of both litchis exhibited a declining pattern, with a more pronounced decline observed in Yuhebao compared to Guiwei. The peroxidase (POD) enzyme activity in the two litchi pericarps exhibited a little decline, whereas the POD enzyme activity in the Yuhebao pericarp was approximately 1.33 times higher than that of Guiwei. Correlation analysis and principal component analysis revealed that total phenols, flavonoids, PPO and pH value were found to have a significant correlation with the browning color of the two litchi varieties. There was a noticeable correlation between the selected litchi varieties and the browning process, indicating distinct differences in the browning status of the pericarp. The findings of this study could offer fundamental data support for future research on suppressing the browning phenomena of litchi pericarp, extracting and processing phenolic active compounds from litchi pericarp.

The microbial community of fruit peel tissues helps to improve fruit quality and resistance to pathogens. There are few reports on the community structure and diversity of endophytic microbes of pitaya peel tissues. This study analyzed the composition and diversity of the endophytic microbial communities in the peel tissues of young healthy fruits and diseased fruits at the early stage of canker disease, and predicted microbial functions to understand the characteristics, through Illumina MiSeq high-throughput sequencing technology. The results showed that there was no significant difference in the diversity and structure of the endophytic bacterial and fungal communities between healthy and diseased peel tissues of pitaya young fruits. In the peel tissues of healthy fruits, Proteobacteria, Actinobacteriota, Firmicutes, Bacteroidota, Deinococcota, Desulfobacteriota and Chloroflexi were the dominant bacterial phyla, and Ascomycota, unclassified_k_Fungi, Basidiomycota and Mucoromycota were the dominant fungal phyla. In the early stage of canker disease, the bacterial phyla Proteobacteria, Actinobacteriota and Deinococcota, as well as fungal phylum Ascomycota, significantly decreased, while bacterial phylum Desulfobacteriota and fungal phylum unclassified_k_Fungi significantly increased in average relative abundance. Compared with the healthy fruits peel, with differences in the proportion of the above microbes, the expression levels of chemoheterotrophy, aerobic chemoheterotrophy, methylotrophic and methanol oxidation functions of endophytic bacteria in diseased fruits peel significantly decreased, the proportion of potentially_pathogenic groups of endophytic bacteria significantly increased, the proportion of saprotroph, pathotroph, pathotroph symbiotroph of endophytic fungi significantly decreased, and the proportion of unknown trophic fungi significantly increased. The results would provide biological information on the endophytic microbes in pitaya fruits peel, to reveal the role in the occurrence of pitaya canker disease and provide theoretical basis for utilizing the function of beneficial microorganisms.

This study aims to screen the microbial strains capable of producing β-D-glucosidase from fermented vanilla pods and apply the screened strains to the fermentation process of vanilla with the goal of enhancing vanillin production and improving the quality of vanilla bean. Septenary selective medium was utilized to isolate β-D-glucosidase producing bacteria, identify the homology of each bacterial strain and measure the production of β-D-glucosidase activity of each strain on two strains with higher enzyme production. The phylogenetic tree was constructed. The two strains of bacteria with the highest enzyme production in different combinations were sprayed onto the fermented vanilla pods. The content of vanillin, vanillin glucoside, and volatile components in different treatments of β-D-glucosidase producing bacteria were determined. Nine strains were successfully screened from the vanilla pods originating in Madagascar (M), and twelve strains were isolated from the vanilla pods produced by Spice and Beverage Research Institute, Chinese Academy of Tropical Agricultural Sciences (S). The fifteen strains were detected as Bacillus. M3 and S7 had higher enzyme activities than other isolates. Vanilla pods treated with M3 obtained the highest vanillin content, which reached to 2.25% and possed the highest aroma components. The maximum decrease in vanillin glucoside content was 80.7% when sprayed with M3 and S7 in a volume ratio of 1:1. There were 34 volatile substances in the fermented pods sprayed with M3, making it the most volatile combination of spraying bacteria. In the present study, we successfully isolated β-D-glucosidase producing bacteria for improving the quality of vanilla pods fermentation.