Rhizosphere is a dynamic interface where soil, plant roots and microorganisms exchange substances. Rhizospheric actinomycetes are an important component of root actinomycetes and one of the main sources of bioactive substances. In this study, five different rhizospheric soil samples of a mangrove plant, Acanthus ilicifolius, were collected from the Dongzhaigang Mangrove Nature Reserve of Hainan province. A combination of high-throughput sequencing and traditional pure culture strategies were used to explore the diversity of the rhizospheric actinomycetes of A. ilicifolius and the potential to produce bioactive substances in the samples. The V3 to V4 regions of 16S rRNA gene in the rhizospheric samples of A. ilicifolius were sequenced and analyzed by Illumina Novaseq 6000 sequencing platform. A total of 32 phyla (including 25 effectively identified phyla) were annotated, of which Proteobacteria is the dominant phyla. α-diversity analysis showed that the rhizospheric bacterial community of A. ilicifolius was very abundant. The microbial communities of actinomycetes were analyzed, and 33 validated genera, four tentative genera and 28 uncultured new genera were noted. KEGG functional prediction analysis in different levels showed that rhizospheric actinomycetes were mainly involved in the biosynthesis of secondary metabolites including various antibiotics. Meanwhile, actinomycetes were isolated by the traditional pure culture method. After isolation, purification, morphological characteristics grouping and rearrangement, the diversity of actinomycetes of mangrove A. ilicifolius was analyzed by PCR amplification, sequencing and comparison of 16S rRNA gene sequences. The antimicrobial activity was screened by the agar diffusion method. PCR-based gene screening technology was used to detect the possible antibiotic biosynthesis genes of the representative strains of PKS-I, PKS-II and NRPS. A total of 33 representative strains of rhizospheric actinomycetes were obtained from four genera, of which Streptomyces was the dominant genus, and 2 genera could not be detected by high-throughput sequencing method. The positive rates of NRPS and PKS-II genes of the representative strains were very high (more than 90%). 24.24% of rhizospheric actinomycetes had the activity against at least one or more indicator microorgnisms. In this study, high-throughput sequencing and traditional pure culture methods were used to show that rhizospheric actinomycetes of a mangrove plant A. ilicifolius from Dongzhaigang had a very rich actinomycetic diversity. The rhizospheric actinomyces of A. ilicifolius has good potential to synthesize secondary metabolites, which could provide rich microbial resources for the screening of bioactive compounds, and also provide an important basis for the development of subsequent new drugs.

In this study, 12 coffee beans from Xishuangbanna (A, B, C), Pu’er (D, E, F), Lincang (G, H, I) and Baoshan (J, K, L) were used as the raw materials to analyze the contents of main flavor precursors and the differences of sensory products. The contents of protein, fat and reducing sugar were determined by the physicochemical analysis. The composition and content of amino acids in samples were determined by an automatic amino acid analyzer. The contents of caffeine and chlorogenic acid were determined by HPLC. 12 green coffee beans were roasted and the sensory quality was measured by cup. The color difference of coffee beans was analyzed by the Colorimetry system. The protein content ranging from 11.73 g/100 g to 14.72 g/100 g, the fat content ranging from 9.1% to 15.9%, the reducing sugar content ranging from 5.83 g/100 g to 6.26 g/100 g. 16 kinds of amino acids were detected in all the 12 samples, and methionine was not detected. The total amino acid content ranging from 10.18 g/100 g to 17.25 g/100 g. The total amino acid content of E coffee beans was the highest, and that of K coffee beans was the lowest. The caffeine content ranging from 13.73 mg/g to 15.74 mg/g, and the chlorogenic acid conten tranging from 20.97 mg/g and 32.51 mg/g. B coffee beans had the brightest color, better color scheduling and tone angle. J coffee beans were rudder than other coffees, and the hue angle was relatively poor. E coffee ripe beans and I coffee ripe beans tended to be blue. E coffee bean had better color scheduling and hue angle preference. The total score of sensory evaluation ranged from 42.79 to 46.09, the sensory score of L coffee bean was the highest, and the sensory score of A coffee bean was the lowest. Therefore, the content of main flavor components of raw coffee beans in different producing areas is different, and the sensory quality of cooked coffee beans in different producing areas is also different. The results are of great significance for the improvement of Yunnan coffee flavor quality and the screening and identification of high-quality products.

Both friable embryogenic callus and suspension cells are ideal materials for genetic and cell engineering. However, the induction of friable embryogenic callus of Hevea brasiliensis is low frequency and time-consuming, and its embryogenic competence usually decreases gradually or even completely loses with the increase of subculture times. Therefore, to quickly obtain friable embryogenic callus, establish embryogenic cell suspensions with high efficiency of somatic embryogenesis, and maintain the embryogenic competence as long as possible, are important research contents for genetic and cell engineering of H. brasiliensis. In this study, the immature anthers of H. brasiliensis clone Reken 525 was used as the explants to induce callus and establish embryogenic cell suspensions, and the effects of two long-term subculture methods-solid and liquid on the maintenance of embryogenic competence were compared and analyzed. The results showed that the yellow and compact primary callus tissue induced from anther explants on callus induction medium had a low ability for somatic embryogenesis, and was not suitable for suspension culture due to poor dispersion. After 70-80 d of culture on the medium for embryogenic callus induction, the formation of embryogenic structures and early somatic embryogenesis were observed, and bright yellow small granular friable embryogenic calli grew around them. The type Ⅰ embryogenic suspension cell line established through routine methods possessed typical characteristics of embryogenic cells, and the frequency of somatic embryogenesis was significantly higher than that of embryogenic callus tissue, but proned to callus formation during somatic embryogenesis; the type Ⅱ embryogenic suspension cell line established by screening specific embryogenic tissue and initiating with low density suspension culture was in an orderly embryonic structure observed by microscope, and its frequency of somatic embryogenesis could reach up to 100%. After two years of continuous subculture in liquid culture medium containing 2 mg/L 2,4-D, the cells were obviously aging with lower proliferation coefficient, and the ability for somatic embryogenesis was almost lost. However, the ability for somatic embryogenesis still remained at a high level after two years of continuous subculture on solid culture medium without 2,4-D but supplemented with abscisic acid (0.1 mg/L) and hydrolyzed casein (0.5 g/L). The type Ⅱ embryogenic suspension cell line could provide high-quality, sufficient and relatively stable material sources for genetic transformation and protoplast culture of Hevea brasiliensis in the long term.

To elucidate the differences in inter-root bacterial communities of Aquilaria sinensis, and to explore the correlation with soil physicochemical properties, we used the high-throughput sequencing technology and bioinformatics-related tools to analyze the composition and multi-characteristics of the inter-root soil bacterial community of A. sinensis. In three cultivation sites in Hainan province (Wenshan village, Haikou city, Dongguang farm, Lingao, and Baolun farm, Ledong), and combined with redundancy analysis to correlate the inter-root soil physicochemical proper-ties with the bacterial community. The results showed that a total of 7 944 402 sequences belonging to 51 phyla,151 orders, 380 families, 637 families, 1296 genera and 2649 species were obtained among the sites; the variability of bacterial community and diversity of A. sinensis in the sample sites was not significant, and there were significant differences among the sample sites. The richness and diversity of inter-root soil bacteria in the sites were as follows: LDJX>LDWJ>LGWJ>LGJX>WSWJ>WSJX. In terms of community structure, the Ledong sample site differed significantly from the Wenshan and Lingao sample sites in terms of community structure.at the phylum level, the dominant bacterial phyla in Ledong were Planctomycetota, Chloroflexi, and Verrucomicrobiota; the dominant populations in Wenshan and Lingao were Firmicutes, Bacteroidota, and Proteobacteria. At the genus level, the dominant genera in Wenshan and Lingao were Bacteroides, uncultured_bacterium_f Muribaculaceae, and Faecalibacterium; the dominant genera in Ledong were the unidentified genus (g_uncultured_f__Gemmataceae) genus, Candidatus_Udaeobacter, and Bacteroides. The RDA analysis revealed that the inter-rhizosphere soil bacterial community of A. sinensis was affected by soil physicochemical factors with some differences among different sites. Total phosphorus was significantly and negatively correlated with bacterial population differences and diversity, and pH was significantly and positively correlated with bacterial population differences and diversity. The results are valuable for studying the interactions of inter-root microorganisms of A. sinensis, and have certain guiding significance for the development of Hainan incense industry.

The variation of volatile aroma compounds and squalene-related enzyme activities of the tissue cultivation of Pandanus amaryllifolius Roxb. leaves (PAL) treated with different concentrations of Zn and La was studied. The volatile aroma compounds were analyzed by GC-MS, and the key enzyme activities of squalene metabolism were detected and analyzed. The results showed that there were differences in the number and content of volatile compounds in the tissue cultivation of PAL treated with different concentrations of trace elements. Compared with the untreated groud, 4 mg/L Zn treatment and 1 mg/L, 2 mg/L, 4 mg/L La treatment had more volatile compounds. Zn and La treatment increased the content of alcohols and decreased the content of olefins. Zn and La treatment significantly reduced the content of squalene. The treatment of 2 mg/L Zn increased the content of β-sitosterol, stigmasterol, ethyl palmitate, 3-methyl-2-(5H)-furanone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4(h)-pyran-4-one, and decreased the content of squalene and phytol. The content of phytol in the leaves of 8 mg/L La treatment was the highest. The activities of squalene metabolism-related enzymes were changed in the process of tissue culture. Lanosterol synthase (LSS) activity and squalene epoxidase (SE) activity were stronger in the mixture, and squalene synthase (SQS) activity was stronger in adventitious roots. Different concentrations of trace elements had a certain effect on the activity of squalene-related enzymes. The content of squalene was positively correlated with LSS enzyme activity, SE enzyme activity and SQS enzyme activity in the PAL treated with different concentrations of Zn. The content of squalene in the tissue cultivation PAL treated with La was negatively correlated with LSS enzyme activity and SQS enzyme activity, and positively correlated with SE enzyme activity. The results would enrich the relevant theoretical research on the regulation of trace elements on the volatile aroma compounds of PAL, and provided theoretical basis for improving the aroma quality of PAL.

AT-hook nuclear localized proteins (AHLs) are small DNA-binding protein motifs that play an important role in plant growth and development, organ construction, stress and hormone signaling response. In this study, MeAHL17 was cloned from cassava cultivar SC8. Bioinformatics methods were used to analyze MeAHL17 promoter, protein physicochemical properties, prediction of conserved functional domain and sequence comparison. The results showed that the open reading frame length of MeAHL17 gene was 939 bp, encoding a protein with 312 amino acids, its theoretical isoelectric point was 6.89, its molecular formula was C₁₄₂₀H₂₂₁₅N₄₁₅O₄₅₁S₁₁, and its molecular weight was 32.669 38 kDa. The total number of positively charged amino acid residues (Lys+Arg) was 23, the total number of negatively charged amino acid residues (Asp+Glu) was 24, the fat coefficient was 57.47, the total average hydrophilic coefficient (GRAVY) was -0.491 and the instability coefficient was 58.06. The protein contains no signal peptide, is located in the cell membrane, has no transmembrane structure, contains 5 glycosylation sites and 45 phosphorylation sites, and is an unstable hydrophilic acidic protein MeAHL17 contained AT-hook conserved core sequences and PPC domain conserved core sequences, which was consistent with the typical structural characteristics of AT-hook family. Through subcellular localization and transcriptional activity analysis experiments, MeAHL17 was proved to be a nucleus localized transcription factor with transcriptional activity. Tissue expression pattern analysis showed that MeAHL17 was mainly expressed in somatic embryo, fibrous root and callus. Different hormone treatments showed that MeAHL17 was induced by ethylene (ACC), methyl jasmonate (JA) and growth hormone (IAA), which suggested that MeAHL17 might be involved in ethylene, methyl jasmonate and growth hormone signaling pathway. Abiotic stress treatment showed that MeAHL17 was responsive to drought and salt stress. This study preliminarily identified the important role of MeAHL17 in growth and development, hormone signaling and stress, and provided theoretical basis and reference for further study of its function.

The plant species in eight coastal parks in Xiamen island were investigated by the sample line method and a total of 288 species of plants in eight coastal parks on Xiamen island were obtained, among which 127 were introduced plants, accounting for 44.10% of the total. 80 species of exotic garden plants with invasive potential were obtained. The risk assessment system of invasive ornamental introduced plants in Xiamen island coastal parks was constructed by the literature collation method and expert consultation, and the evaluation index weights were determined by the hierarchical analysis method. The evaluation system includes one target level, five primary indicators and twenty secondary indicators. 80 exotic landscape plants with invasive potential were substituted into the risk assessment system of introduced landscape plants in Xiamen island Coastal Park to obtain the corresponding scores. 13 species with scores between 38.00 and 58.85 were considered high-risk plants. 18 species with scores between 23.00 and 38.00 were medium-risk plants. Nine species with scores between 9.30 and 23.00 were low-risk plants. Four high-risk plants that are not listed in the Chinese Invasive Alien Plant Register should be detected early and controlled with effective management measures. Medium-risk plants should be phased out and replaced with native plants, and low-risk plants should be monitored and managed. Most of the ornamental introduced plants in the eight coastal parks in Xiamen island are low-risk plants. Among them, Wutong Lighthouse Park, Bay Park and Niu Tou Mountain Park are among the top three in the number of applied introduced plant species, and it is recommended that no more ornamental introduced plants be introduced in the future. Music Square had the least number of introduced plants, and it is recommended to introduce low-risk plants to increase the vegetation diversity of the park. This study sorts out the introduced plant species in Xiamen island coastal parks and proposes relevant control suggestions for introduced plants, protects the ecological security of Xiamen island coastal parks, further enriches the invasion risk evaluation studies in small-scale areas and provides a reference for the introduction of introduced plants in coastal parks in other areas.

Grey mold is a common disease in tomato production caused by Botrytis cinerea, a necrotrophic pathogen, which often leads to dramatic reduction of tomato yield. Sucrose catabolism plays an important role in plant defense against pathogen infection by providing carbon skeleton and energy for plant defense responses and/or regulating the expression of defense-related genes through signaling pathway. Previous studies have shown that cell wall invertase (CWIN), a kind of sucrose-degrading enzyme, can enhance plant resistance to several necrotrophic pathogens. However, no research has been conducted to study the role of CWIN in tomato resistance to B. cinerea. In this study, wild type tomato (W) and its transgenic line (R) with elevated CWIN activity were used as materials to study the effect of CWIN on tomato resistance to B. cinerea (Bc) via in vitro inoculation. In addition, inoculated leaves were sampled 12 h and 60 h post inoculation (hpi) for RNA-Seq to elucidate possible molecular mechanisms underlying the regulation of CWIN to tomato resistance against B. cinerea. The results are as follows: (1) Elevated CWIN activity enhanced tomato resistance to B. cinerea; (2) KEGG annotation showed that DEGs (W-Bc-12 h-vs-R-Bc-12 h) from 12 hpi were significantly enriched in five pathways, including biosynthesis of secondary metabolites, metabolic pathways, DNA replication, starch and sucrose metabolism, and steroid biosynthesis; No significant enrichment pathway was found for DEGs (W-Bc-60 h-vs-R-Bc-60 h) from 60 hpi. (3) By mapping DEGs to plant-pathogen interaction pathway, it was revealed that the LRR-receptor serine/threonine-like kinase gene FLS2 and heat shock protein gene HSP90 involved in hypersensitive response and defense-related gene induction were up-regulated in RNAi leaves after inoculation, indicating the two genes may participate in the regulation of CWIN to tomato resistance to B. cinerea. (4) The analysis of plant hormone signal transduction pathways and MapMan mapping showed that the signal pathway of jasmonic acid (JA) and ethylene (ET) was enhanced in RNAi leaves after inoculation, while the signal pathway of salicylic acid (SA) was weakened, indicating that the hormones might work together to improve the resistance of RNAi tomato to B. cinerea. In addition, the signal transduction of growth-promoting hormone auxin (IAA) and cytokinin (CTK) was also enhanced in RNAi leaves after inoculation, but that of senescence-promoting hormone abscisic acid (ABA) was weakened. The changes in signal pathways of IAA, CTK and ABA could inhibit the cell death in host during bacterial infection, thus preventing the necrotrophic pathogen B. cinerea from obtaining necessary nutrients from the dead host cells for its infection. In addition, MapMan mapping also revealed that cell wall thickening, proteolysis, reactive oxygen species (redox state and peroxidases) and secondary metabolites were also greatly enhanced in RNAi leaves after inoculation, which all contribute to improving the disease resistance of tomato. In conclusion, this study showed that elevated CWIN activity enhanced tomato resistance to B. cinerea. Transcriptome analysis not only verified the existing molecular mechanisms underlying the regulation of CWIN to plant resistance to microbial pathogens, such as cell wall thickening, accumulation of reactive oxygen species (ROS) and hypersensitive response (HR), accumulation of resistance hormones (SA and JA/ET), biosynthesis of pathogenesis-related protein (e.g. PR and HSP proteins) and secondary metabolites (such as phytotoxins and phenolics), but also revealed several possible new mechanisms including the signal transduction of growth-promoting hormone (IAA and CTK) and senescence-promoting hormone (ABA) and proteolysis. This study can provide theoretical guidance for the improvement of tomato resistance to B. cinerea by using modern biotechnologies such as genetic engineering and molecular breeding.

The aim of this study was to explore the protective effect of arecoline on the cell model of H₂O₂-induced oxidative stress damaged model in SH-SY5Y cells and elucidate its mechanism. Cell viability was detected by CCK-8 assay. Spectrophotometry was used to detect LDH release, MDA, SOD, and CAT contents. Flow cytometry was used to detect cell apoptosis and mitochondrial membrane potential. Western blot was used to detect the expressions of Nrf2, HO-1, Keap1, Bcl-2, Bax and Caspase-3. Arecoline could reduce cell apoptosis and significantly increase mitochondrial membrane potential. The level of SOD elucidateand CAT increased while the level of MDA decreased. Arecoline 140 μmol/L group could significantly up-regulate the protein expression of Nrf2, HO-1 and Bcl-2 (P<0.001, P<0.0001), and down-regulate the protein expression of Keap1, Bax and Caspase-3 (P<0.001, P<0.0001). Conclusions: arecoline can effectively improve H₂O₂-induced oxidative stress injury in SH-SY5Y cell by activating the Nrf2/HO-1 signaling pathway, enhancing the activities of antioxidant enzymes and regulating the oxidation reduction system of cells, as well as regulating the Bcl-2/Bax/Caspase-3 signaling pathway and inhibiting cell apoptosis.

The present work was conducted to identify the pathogen causing anthracnose of Liberica coffee (Coffea liberica) plants and to screen fungicides against the disease pathogen. The leaves of C. liberica with anthracnose symptoms were sampled from fields for fungal isolation and purification. Four pure fungal isolates were obtained and only KFTJ01 was verified pathogenic to the coffee leaves by tests following Koch’s Postulates. The rDNA-ITS sequence (554 bp), beta-tubulin gene (tub2) and calmodulin gene (CAL) were successfully amplified via PCR from genomic DNA of KFTJ01 and sequenced. Blastn analysis of the the three DNA sequences showed that KFTJ01 was identical to the strain WZ-135 (99.62%, MN856281), CREADC-ER2212 (100%, MT409131) and YMTJ4 (100%, MK569149) of Colletotrichum kahawae. KFTJ01 was also clustered with C. kahawae WZ-135 strain on the same end-branch of the phylogenic tree (bootstrap confidence is 98%). Therefore, the pathogen of Liberica coffee was identified as C. kahawae which is a quarantine species and has never been recorded in China. Fungicide selection experiments showed that among the 10 chemicals, methionine-acetazolyl and methyl thiobacillam almost completely (100%) suppressed the colony growth of KFTJ01. The median effective concentration calculated from the functions was 0.0607 mg/mL and 0.0809 mg/mL, respectively, indicating that both the chemicals were very effective against the anthracnose pathogen. The results are important references for the field diagnosis of the coffee plant anthracnose and for controlling the disease epidemics.