In order to provide technical support for risk management, risk analysis and risk assessment of pests carried by citrus seedlings in China were carried out. Through consulting domestic and foreign literature, a total of 259 species of pests that may be transmitted to banana seedlings exported to China were determined, including 53 fungus, 9 bacteria,9 viruses, 11 nematodes, 167 insects, 1 mollusc, 1 weed, 8 mites (including spiders). According to the distribution of pests in China (not distributed or not widely distributed), whether it is officially controlled, and the possibility of carrying with banana seedlings, 18 potential quarantine pests were determined to be further evaluated, including 4 fungus, 7 bacteria, 4 viruses, 2 nematodes and 1 insect. The 18 potential quarantine pests were qualitatively and quantitatively analyzed one by one in terms of entry, colonization, possibility of spread, economic impact and comprehensive evaluation of multiple indicators, and 14 high-risk pests and 4 extremely high-risk pests were identified. The quarantine risk of citrus seedlings imported to China was determined to be extremely high based on the highest risk level among all quarantine pests. Finally, 18 types pests including Bisifusarium dimeru on citrus seedlings imported to China were identified, and corresponding risk management measures were proposed.

Grapefruit of Guipuyou No. 1 planted in Guangxi has high and stable yield, and the flesh is juicy, suitably acidic and sweet. The widely targeted metabolisms of flesh was determined, the differential metabolites were screened and the metabolic pathway was analyzed to understand the difference of flesh composition at different maturity stages. A total of 529 metabolites were detected from grapefruit of Guipuyou No. 1, including 159 flavonoids, 64 Phenolic acids,64 amino acids and derivatives, 53 others (saccharides and alcohols, vitamin, others), 51 lipids, 40 lignans and coumarins,34 nucleotides and derivatives, 29 alkaloids, 28 organic acids, 5 terpenoids and 2 tannins. The differential metabolites at different maturity stages mainly included flavonoids, phenolic acids, amino acids and their derivatives, lipids, lignans and coumarins, and most of them were down-regulated. The down-regulated types of phenolic acids, amino acids and their derivatives, lipids and other types increased, and most of them showed a continuous downward trend with the increase of fruit ripeness. Most of the down-regulated flavonoids showed a sharp decline in the early stage of fruit ripening, and then increased in the late stage of fruit ripening. The types of down-regulated flavonoids first increased and then decreased, with the most in the middle stage of fruit ripening. The relative contents of synephrine, spermidine, betaine, shikimic acid were consistently decreasing. The relative content of limonin increased in the early stage of fruit ripening, and decreased significantly in the middle and late stage of fruit ripening. The most significant enrichment pathway of differential metabolites was flavonoid biosynthesis in the early stage of fruit ripening, but it was phenylpropanoid biosynthesis during the whole ripening process. The fruit of G₂ had the best taste, with soluble solids of 12% and solid-acid ratio of 23.24, which was suitable for fresh eating. However, phenolic acids such as caffeic acid and ferulic acid, flavonoids such as isoquercitrin and hyperoside decreased significantly during this period. There were many kinds of metabolites in the pulp of grapefruit of Guipuyou No. 1, which was rich in nutritional and functional components. The best picking time for fresh food is from late October to middle November. Fruits used for health care or medicinal purposes should be picked in advance according to the efficacy requirements. This study would provide a theoretical basis for the study on the nutritional and functional components of grapefruit of Guipuyou No.1, and provide a reference for the best harvest maturity of its different uses.

Starch sodium octenyl succinate is a food additive produced by the process of esterification using starch and octenyl succinic anhydride. In this study, the tapioca starch sodium octenyl succinate was prepared and characterized with non-alcohol esterification by substituting the organic reagent-dispersed OSA with the OSA emulsification technique. The results showed that OSA emulsion prepared with soybean phospholipid (SP) as an emulsifier had good stability and dispersibility. The octenyl succinic acid group content, degree of substitution, and substitution efficiency of 1.00% SP-SSOS made using OSA emulsions with 1.00% SP emulsifiers were found to be greater compared to IPA-SSOS made using isopropanol-dispersed OSA. FT-IR showed that 1.00% SP-SSOS and IPA-SSOS had two new characteristic peaks at 1572 cm^–1 and 1726 cm^–1, with 1.00% SP-SSOS having a stronger peak intensity. Confocal laser scanning microscopy confirmed that the fluorescence intensity of the fluorescence-labeled OS group was slightly stronger in 1.00% SP-SSOS, and a few starch particles contained OS groups inside. The results indicated that the use of high-pressure homogenization and emulsifiers to disperse OSA into micron-sized oily droplets for esterification could increase the contact area between OSA and starch, improving the efficiency of the esterification reaction. To summarize, it is possible to produce SSOS by utilizing the OSA emulsification technique as an alternative to organic reagents for dispersing OSA. This study would provide a reference for the application of an alcohol-free esterification reaction system in the large-scale industrial production of SSOS.

Mikania micrantha is one of the first invasive species in China, which poses a big threat to the ecological security of subtropical regions. Soil enzyme activity inhibitors and plant growth regulators play central roles in plant growth regulation. In this paper, the effects of different concentrations of soil enzyme activity inhibitors [1 g/L and 15 g/L NBPT, N-(N-butyl) thiophosphate triamide, 1 g/L and 15 g/L nitrification inhibitor DMPP] and exogenous plant regulators (25 mg/L and 50 mg/L ABA, abscisic acid, 1 g/L and 10 g/L CCC, chlormequat) on the growth of M. micrantha during its vigorous growth period, budding period, flowering period, peak flowering period, and seed setting period were studied through a 7-month continuous pot culture experiment. The results showed that high and low concentrations of soil enzyme activity inhibitors and plant growth regulators had different effects on the growth status of chamomile and the content of alkaline hydrolyzed nitrogen and available phosphorus in the soil. Among them, chloramphenicol and DMPP had a significant inhibitory effect on chamomile, while 15 g/L NBPT had a promoting effect on chamomile growth. In summary, 10 g/L chloramphenicol had an inhibitory effect on the vigorous growth of chamomile, while 15 g/L DMPP had an inhibitory effect on the vigorous flowering period of chamomile. The combined application of the two could provide a theoretical basis for the comprehensive prevention and control of chamomile throughout its lifecycle.

The purpose of this study is to explore the relationship between the activity of Lvnonglin^®31 compound microbial agent (LNL31), the occurrence of blister blight and the structure of endophytic bacterial communities in tea, and to provide a theoretical basis for the rational application of microbial agents for green control of blister blight in Camellia sinensis var. assamica. The activity of LNL31 was evaluated through indoor antibacterial spectrum testing, laser confocal microscope morphology observation, pathogenic fungus spore germination inhibition rate test, and transparent circle detection enzyme activity methods. Field randomized block trials were carried out to test the disease prevention and growth promotion effects of LNL31 with different dilution ratios. Then the tea tree bud length, bud density, fresh weight and chlorophyll were respectively measured. Using 16S rDNA sequencing technology, the differences in the occurrence of the blister blight in C. sinensis var. assamica and the community structure of endophytic bacteria in leaves under LNL31 were investigated. The diluted LNL31 had obvious inhibitory effect on five pathogens, such as Exobasidium vexans EV01, Colletotrichum gloeosporioides CG02, Fusarium oxysporum FOC4, Xanthomonas axonopodis pv. citri XC01 and Escherichia coli DH5α, which caused the hyphae to break, expand and digest. The inhibition rate of LNL31 on spore germination of pathogenic fungi EV01, CG02 and FOC4 reached 89.04%-93.00%. In field randomized block trials, the application of 500-fold dilution of LNL31 had the most significant disease prevention and growth promotion effect, which was similar to the treatment of the pyraclostrobin, followed by 1000-fold dilution of LNL31. The averages of bud length, germination density, hundred bud weight and chlorophyll of the plants in the treatment of LNL31 increased by 23.14%-36.17%, 32.10%-51.38%, 27.66%-40.00% and 28.88%-36.14%, respectively, in comparison with the control. After spraying different concentrations of LNL31, the richness and uniformity of endophytic bacterial communities increased, and the results of principal coordinate analysis (PCoA) showed that there was a significant impact on bacterial communities in leaves. At the taxonomic level, Rhizobiales and Sphingomonadales were the dominant bacterial orders; Methylobacterium was the dominant bacterial genus, followed by 1174_901_12, Sphingomonas and Rhizobium. Linear discriminant analysis (LEfSe) showed that there were 9-14 indicator bacterial groups in the treatment sprayed with LNL31, compared with only 7 indicator bacterial genera in the control. Cluster analysis of species abundance showed that the unique dominant genus Baierinkia and Burkholderia in the treatment of LNL31 were similar in abundance, while Rhizobium and 1174_901_1 were similar in abundance. Correlation network analysis Bacillus is positively correlated with Eubacterium and Parabacteroide, and negatively correlated with Methylobacterium, Beijerinckia and Luteibacter. Bugbas's functional prediction showed that the abundance of aerobic bacteria, biofilm forming, gram-negative bacteria, stress-tolerant bacteria, movable elements, and facultative anaerobic bacteria treated by the composite microbial agent increased by 3.24%-14.78%, and potential pathogenic bacteria dropped by 5.70%. LNL31 showed a good effect of preventing diseases and promoting growth, and significantly changed the community structure and functional characteristics of endophytic bacteria in tea, enabling a few disease-resistant related species to grow in an advantageous way, which provided a basis for biological control of blister blight of tea.

In this study, the microbial community was analyzed by high-throughput sequencing technology in the soil of rubber plantation with different yield levels (high yield, middle yield, low yield and none yield), and relationship between microbial community and soil physical and chemical properties was also studied. A total of 2116 bacteria OTUs were obtained from all examined samples, which belonged to 17 phyla, 53 classes, 99 orders, 164 families, 305 genera and 385 species. The dominant phyla of bacterial community were Acidobacteria, Proteobacteria and Firmicutes. A total of 1622 fungal OTUs were obtained from all soil samples, which belonged to 17 phyla, 49 classes, 113 orders, 242 families, 424 genera and 644 species. The dominant phyla of fungal community were Basidiomycota, Ascomycota and Mortierellomycota. The abundance of soil bacteria community showed a downward trend was observed with the decreasing of the yield level of rubber trees, while the difference of bacterial diversity index was not significant. Ace index and Chao1 index of soil fungi showed an upward trend, and Shannon index significantly increased, while the Simpson index decreased significantly, indicating that the richness and diversity of fungal community increased with the decreasing of the yield level. Principal coordinate analysis (PCoA) showed that the community structure of soil bacteria or fungi was significantly different under the treatments. In addition, the relative abundance of dominant bacterial phyla also varied to different degrees. The characteristics of soil microbial community were closely related to soil pH and C/N. According to redundancy analysis (RDA) results, soil pH, available potassium and total nitrogen were the main soil physical and chemical factors affecting the dominant bacterial phyla, while the dominant fungal phyla were mainly affected by soil pH, available potassium and C/N.

Pitaya fruit is a characteristic tropical fruit of Hainan province, mainly cultivated in the red soil of Hainan province. The exchangeable magnesium is lost throughout the year, leading to magnesium deficiency in some orchards, which affects the growth and yield of pitaya fruit. Magnesium is involved in photosynthesis and other metabolic processes. Therefore, this study took the main domestic variety of pitaya Dahong as the experimental material, using hydroponic experiments, set four magnesium concentration gradients of 0, 0.5, 2.0, 4.0 mmol/L, to determine the changes in the apparent morphology, biomass, and the activity of enzymes related to crassulacean acid metabolism in pitaya fruit. The results showed: (1) Different magnesium concentration treatments had a significant impact on the length, width, thickness, stem thickness, and fresh weight of the tender stems of pitaya fruit. When magnesium is deficient or excessive, the length, width, thickness, stem thickness, and fresh weight of the tender stems are also significantly less than those treated with 2.0 mmol/L. Magnesium deficiency can significantly reduce the length, width, thickness, stem thickness, and fresh weight of pitaya fruit. The condition of 2.0 mmol/L magnesium concentration is most suitable for plant growth; (2) The activity of PEPC first increased and then decreased with the increase of magnesium concentration. The activity of PEPC at 4 mmol/L magnesium concentration was lower than at 2.0 mmol/L but higher than at 0.5 mmol/L and 0 mmol/L treatments. after 84 days, under the condition of 2.0 mmol/L magnesium concentration, the PEPC activity in tender and old stems was the highest among other treatments, at 90.44±1.40 and 92.77±0.67 nmol/(min·g), respectively, and its initial CO₂ fixation ability was much higher than other treatments; The activity of NAD-MDH in tender stems decreased with the increase of magnesium concentration. With the extension of treatment time, the impact of magnesium concentration on NAD-MDH gradually appeared, first observed in tender stems and then gradually affected the old stems. The maximum activity of tender and old stems treated with magnesium deficiency after 84 days was (12631.82±286.04)nmol/(min·g), and (10500.16±108.34) nmol/(min·g), respectively; Under the treatment of 2.0 mmol/L magnesium concentration, the activity of NAD-ME in both tender and old stems of pitaya fruit was maintained at a high level, with an overall average of 28.41~ 65.87 nmol/min/g. (3) Magnesium deficiency had a significant effect on the enzyme activities of PEPC and NAD-MDH in tender stems. Magnesium deficiency reduced the activity of PEPC, leading to a decrease in oxaloacetic acid content, limiting the process of CO₂ conversion to malate. The accumulation of malate at night is reduced, and the raw materials for photosynthesis are insufficient during the day, thereby reducing the accumulation capacity of organic matter. Conclusion: The optimal magnesium concentration for the cultivation of domestic red-fleshed pitaya is 2.0 mmol/L. The magnesium concentration in the soil of the current pitaya planting area is lower than this value, so it is recommended to reasonably increase the application of magnesium fertilizer during the planting of pitaya.

The biological macromolecules such as polysaccharides and terpenes in Sanghuangporus spp. aqueous extract have inhibitory effects on tumor cells, but the function was not yet clear. This study obtained small molecule compounds of Sanghuangporus sanghuang Sheng H. Wu, L. W. Zhou & Y. C. Dai and Phellinus baumii aqueous extracts through 3000 D ultrafiltration, and studied the inhibitory activities on mouse hepatocarcinoma cells Hepa 1-6 using dual fluorescence labeling. The anticancer active ingredients were analyzed using metabolomics analysis. The results showed that the small molecule compounds of S. sanghuang Sheng H. Wu and P. baumii could induce injury and apoptosis of Hepa 1-6, with inhibition rates of (38.64±4.35)% and (32.52±3.57)%, respectively. Meanwhile, the inhibition rates of small molecule compounds reached (77.27±6.21)% and (76.92±5.45)%, respectively, after mixing with crude polysaccharides. Metabolomic analysis showed that anti-cancer small molecular agents such as ellipticine, betonicine, cerebroside-B etc., were identified in the aqueous extract of Sanghuangporus spp. Antitumor related substances such as heterocyclic compounds (6-fluoroindole, 2,4,6-trimethylpyridine, 1'-naphthoyl-2-methylindole, etc.), nucleoside and bases (1-methyladenosine, N6-methyladenosine, 2'-O-methyladenosine, etc.), dipeptides (leucine+*, isoleucine+*, γ-glutamine+*, etc.), sugar alcohols (xylitol, ribose, mannitol, erythritol, etc.), were identified too. The results indicate that the aqueous extract of Sanghuangporus spp. contains multiple small molecular agents against tumor cells, which have a synergistic anti-cancer effect with biological macromolecules such as polysaccharides. This would provide a scientific basis for understanding the mechanism of anti-tumor of Sanghuangporus spp. and the development and application of functional substances.

Phosphorus is one of the essential nutrients for plant growth, and plays a crucial role in determining crop yield and quality. Due to the combined pressure of decreased arable land quality and soil phosphorus deficiency or low bioavailability, the improvement of soil phosphorus availability has become a global concern. The rotation of two or more crops has positive effects on soil improvement, crop production efficiency and the restoration of agricultural ecosystem function. This study reviews the research progress on the effects of crop rotation on soil physiochemical properties, soil phosphorus transformation, and soil micro-food web. Firstly, the relationship between soil properties and phosphorus transformation is analyzed to assess the impact of crop rotation on phosphorus availability. Secondly, from the perspective of soil micro-food web and gene regulation, the transformation and biogeochemistry cycle of soil phosphorus was analyzed at the molecular level. It is summarized that crop rotation can affect soil phosphorus transformation through altering soil physiochemical properties and micro-food network structure, which can improve soil phosphorus availability, and ultimately promote crop yield and quality. We indicate that crop rotation is an important agricultural management measure for improving soil phosphorus availability. It is suggested to strengthen the related research and explore the combination model of crop rotation in the future. It would provide powerful support for food security and crop quality, and is of great significance in social economy and ecological environment.

Lysophosphatidyl acyltransferase (LPAT), a key enzyme which controls the production of lysophosphatidic into phosphatidic, plays an important role in phospholipid biosynthesis in plants. Hevea brasiliensis is an important source for the production of natural rubber, which has an irreplaceable role in the fields of national defense, medical treatment, high-end products, and has high social and economic value. Cloning and analysis of HbLPAT2 in H. brasiliensis would provide scientific basis for further exploration of its phospholipid biosynthesis function and the effect of phospholipid on nature rubber. In this study HbLPAT2 was cloned from the latex of the H. brasiliensis by molecular biology techniques, and the bioinformatics analysis, expression analysis and subcellular localization analysis were performed. In this study, two key genes responsible for phospholipid biosynthesis in the HbLPAT gene family were successfully cloned from the latex of the H. brasiliensis, named HbLPAT2a and HbLPAT2b, the full length coding sequence of HbLPAT2a and HbLPAT2b genes was 1161 bp and 939 bp, encoding 386 and 312 amino acids. Both HbLPAT2a and HbLPAT2b contained a PLN02380 lysopyatidyl acyltransferase functional domain and contained a highly conserved NH(X)₄D motif; HbLPAT2a protein had 3 transmembrane domains, and HbLPAT2b protein had 1 transmembrane domain, both of which had no signal peptide, were hydrophilic proteins, and contained multiple phosphorylation sites. The subcellular localization analysis showed that both HbLPAT2a and HbLPAT2b proteins were located in the endoplasmic reticulum. In different organs, the highest expression level of HbLPAT2a and HbLPAT2b was found in seeds, suggesting that they have a lipid biosynthesis function. However, in the latex of H. brasiliensis, the first and second expression level of whole HbLPAT gene family were HbLPAT2a and HbLPA2b. The result is helpful to understanding that HbLPAT2a and HbLPAT2b play an important role in the phospholipid biosynthetic pathway in latex of H. brasiliensis and to providing a scientific basis for genetic improvement of latex quality of H. brasiliensis.