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.

Powdery mildew caused by Erysiphe quercicola is a significant disease in China’s natural rubber industry, posing a severe threat to latex production. With the continuous advancement of predictive and forecasting technologies, the combination of qPCR detection and spore capture techniques holds promise as an efficient method for predicting the prevalence of powdery mildew. In this study, we focused on the microscale extraction of DNA from rubber tree powdery mildew spores. We compared various pre-treatment methods, different types of grinding beads with varying materials, and different types of grinding machines to identify the most suitable spore sample grinding system. Furthermore, we compared the efficiency of the CTAB method with several commercial extraction kits. Ultimately, we established a feasible microscale DNA extraction method for spores: first, the powdery mildew spore water solution subjected to 4 ℃ultrasonication for 10 min, subsequently, 2 mm zirconia beads (0.2 g), glass beads (0.4-0.6 mm, 0.2 g), and 0.2 mm zirconia beads (0.2 g) added, tissue grinder 70 Hz at 4 ℃, grind 40 s, stop 10 s, 20 cycles, finally, DNA extracted using the CTAB method. This method effectively and stably extracts DNA from 10¹ spores/mL rubber tree powdery mildew spores, without being affected by complex field conditions, and demonstrates high sensitivity and specificity. It provides a reliable theoretical basis and an effective technical approach for the prediction and forecasting of rubber tree powdery mildew.

Cassava mosaic disease (CMD) poses a serious threat and danger to cassava production in China and the world, and there is no effective control method and lack of resistant materials, causing serious economic losses, and is considered one of the most threatening viral diseases. Sri Lankan cassava mosaic virus (SLCMV) is one of the major pathogens causing cassava mosaic disease. RNA silencing is an innate antiviral immune response mechanism in plants and animals, and post transcriptional gene silencing (PTGS) is a conserved gene expression regulatory mechanism in eukaryotes, and is one of the important antiviral immune mechanisms. Suppressor of gene silencing 3 (SGS3) is a key protein of the PTGS pathway and plays a critical role in host defense against viral invasion. To counteract this host immune response, viruses usually encode viral suppressors of RNA silencing (VSRs) to counteract the viral defense mechanism of host PTGS, and interaction with host proteins is one of the main mechanisms of action for the silencing suppressors to function. In order to investigate whether SLCMV AC2 inhibits the immune function of host PTGS by interacting with AtSGS3, we analyzed the immune function of host PTGS by using yeast two-hybrid (Y2H) system and bimolecular fluorescence complementation (BiFC) experiments, to analyze the interaction between AtSGS3 and SLCMV AC2. The results showed that SLCMV AC2 interacted with AtSGS3 protein in both yeast cells and plants. In subcellular co-localization experimental studies, we further demonstrated that SLCMV AC2 could co-localize with AtRDR6, a close partner of AtSGS3, after interacting with AtSGS3. The data suggest that SLCMV AC2 may affect the host autoimmune mechanism and enhance viral pathogenicity by interacting with siRNA-body, and that the interaction between SLCMV AC2 and AtSGS3 may be the molecular basis for the development of foliar symptoms in SLCMV-infected cassava, and the results of this study would provide a new theoretical basis for the subsequent in-depth analysis of the pathogenicity mechanism of SLCMV.

Banana Fusarium wilt is a fungal disease which is the most harmful and difficult to control in banana production in China. Due to the influence of banana Fusarium wilt, the banana planting area in China has been decreasing year by year in recent years, which has brought huge economic losses to the subtropical and tropical banana industries in China. The disease occurred because the vascular bundle of banana was invaded by Fusarium oxysporum f. sp. cubense (Foc), and its propagation speed was fast, which caused the yellowing of banana leaves and plant wilting. By comparing the genome and transcriptome sequences of Foc race 1 (Foc1, N2) and race 4 (Foc4, B2), a secreted protein FoSP1 located in the lineage-specific region with high expression was screened out. The results showed that the open reading frame of FoSP1 gene was 387 bp, encoding 129 amino acids, and its signal peptide cleavage site was located between the 20th and 21st amino acid residues, and the protein had no known domain and functional site, so it was inferred that FoSP1 was a new secreted protein. In order to study the biological function of the protein in Foc4 strain, the split-marker method was used to knock out the FoSP1 gene of B2 strain, and the phenotype analysis and pathogenicity determination of the correctly knocked-out mutant were carried out. The results showed that compared with wild-type B2 strain, there was no significant difference in the vegetative growth of FoSP1 gene knockout mutants, and they were insensitive to exogenous stresses such as NaCl, D-sorbitol and H₂O₂, but the conidial yield and germination rate of knockout mutants were significantly reduced, and their pathogenicity to Brazilian banana was significantly weakened. It is inferred that the secreted protein FoSP1 does not participate in the vegetative growth of B2 strain, but plays an important role in the process of sporulation and pathogenicity. This result lays a foundation for further study on the pathogenic mechanism of secreted proteins in the genome lineage-specific region of Foc4.

Tigernut (Cyperus esculentus L.) is an herbaceous oil crop uniquely accumulating a high level of oil in the underground tubers. Water, which accounts for approximately 85% of immature tubers, is essential for tuber development and metabolism. Plasma membrane intrinsic proteins (PIPs) represent the main channel that mediates the efficient water transport across the cell membrane. This study presents the characterization of CePIP2;1, a PIP gene highly abundant in tigernut tubers. This gene with three introns was shown to encode 288 amino acids with the theoretical molecular weight of 30.34 kDa, the isoelectric point of 8.60, the grand average of hydropathicity of 0.529, and the instability index of 29.60, implying it’s stable, basic and hydrophobic characteristics. The protein was shown to possess one conservative MIP (major intrinsic protein) domain, and presence of the F-H-T-R ar/R selectivity filter and Q-S-A-F-W Froger’s positions implies a putatively efficient water transport activity. Phylogenetic analysis revealed that CePIP2;1 clusters with OsPIP2;1, OsPIP2;2, and OsPIP2;3 with the similarities of 91.72%, 90.31% and 84.98%, respectively, supporting its assignment into the PIP2 group of the PIP subfamily. Subcellular localization analysis showed that CePIP2;1 was localized to the cell membrane of Nicotiana benthamiana leaves. Although CePIP2;1 was characterized as a dominant isoform in tubers, expression analysis indicated that its transcripts were relatively more in leaves, leaf sheaths, rhizomes, and roots with the most in leaves, in contrast to a comparable level to that in shoot apexes. Among four typical stages (S₁–S₄) of tuber development examined in this study, CePIP2;1 was shown to exhibit a bell-shaped expression pattern, peaking at S₂. These results laid a solid foundation for further uncovering the mechanism of water balance in tigernut.

This study was conducted to compare the difference of heat tolerance of different Oncidium cultivars, and to establish a system for evaluating identification indexes of Oncidium heat tolerance. Seven indexes, including the leaf thickness, leaf water content and high temperature semi-lethal temperature (HLT₅₀), of 38 common O. hybridum cultivars were measured, and the yellow leaf rate and heat injury grade (HIG) of different cultivars were observed under high temperature stress. The evaluation indexes of heat tolerance of Oncidium were screened by analyzing the correlation among different indexes and combining with principal component analysis, to establish the evaluation system of heat resistance of Oncidium cultivars. The results showed that the leaf thickness, leaf water content, HLT₅₀, yellow leaf rate and HIG could well reflect the response of Oncidium to high temperature stress, which could be taken as the index for evaluating Oncidium heat tolerance. The 38 cultivars could be classified into three categories: heat-tolerant cultivars (12 cultivars), moderate heat-tolerant cultivars (3 cultivars) and non-heat-tolerant cultivars (23 cultivars) by cluster analysis based on heat-tolerant index. The results of this study could provide a reference for material selection of Oncidium in hot area, and also provide parental resource for the breeding of Oncidium with high heat tolerance.

Rhynchostylis is an epiphytic orchid belonging to the Orchidaceae family. It possesses high ornamental and economic value. In this study, based on the collection of 10 different germplasm resources from three common species of Rhynchostylis, 21 pairs of SSR polymorphic primers were selected using fluorescent-labeled capillary electrophoresis for allele variation detection. Among them, 13 primer pairs exhibited high polymorphism, resulting in a total of 47 amplified alleles. The average number of observed alleles (N_a) was 2.238, and the average number of effective alleles (N_e) was 1.860. The observed heterozygosity (H_o) of the 21 loci ranged from 0 to 0.778, with a mean of 0.421, while the expected heterozygosity (H_e) ranged from 0.148 to 0.574, with a mean of only 0.340. The Shannon index (I) ranged from 0.096 to 0.987, with a mean of 0.567. The clustering results and PCoA analyses of the 10 germplasm were consistent with the traditional botanical classification, and all the germplasm could be classified into three taxa by species. On this basis, four pairs of core primers were selected to construct a molecular ID for each germplasm. This study lays a foundation for the collection, conservation, identification, development and utilization of the germplasm resources of Rhynchostylis.

This paper reports a new record Orchidaceae genus—Vandopsis Pfitz, and two new record species—V. gigantea (Lindl.) Pfitz and Dendrolirium tomentosum (J. Koenig) in Guangdong province. The detailed morphological description, habitat distribution and color photos are provided. The findings expand the distribution range of those taxons and is of great significance to the flora study.

The sisal zebra disease, caused by fungal pathogen Phytophthora nicotianae Breda, is one of the main diseases in sisal, which seriously affects the development of sisal industry. The pathogenic mechanism is not clear up to now. In order to obtain new anti-zero disease sisal variety, Yuexi 114 and H.11648 were used as the parents to breed new offsprings. Rema No.1 is one of the backcross progenies of Yuexi 114 and H.11648. Morphological traits including leaf shape, leaf color, have/none marginal spine, apical spine type, leaf length, leaf width, thickness of leaf base, length of apical spine, and spine basal width, plant height, inflorescence shape and flower stalk height, number of pedical, flower, fruit and seed characters, number of leaf, fiber ratio were examined. Ploidy level, genome size and resistance to P. nicotianae Breda was determined by an analysis of wall removal and low permeability flame drying method, flow cytometry, and inoculating P. nicotianae Breda in field and lab respectively. Rema No.1 is characterized by the presence of gray green, fleshier and rigid, sword-leaf with wax powder on the leaf surface, 1.2-2.0 cm apical spine, none marginal spine. Leaf length, leaf width and leaf base is about 130 cm, 16 cm, and 3.5 cm, respectively. The leaves rise in a spiral arrangement around the stem. Rema No.1 is also characterized by plant height 1.8-2.5 m, flower stalk 3-7 m, paniculate inflorescence, with 20-32 pedicals, complete flower, yellow flower with 6 petals, oblong capsule, dark brown to almost black upon maturity, lunate black seeds, marginate. leaves 360-400, leaf fiber ratio 3.5%, fiber length 100 cm. The life span is 6-9 years. Rema No1 is tetraploid (2X=4n), chromosome number is between 104-118, the genome size of Rema No. 1 is 2C=11.69 pg. Rema No.1 is high resistant to Phytophthora nicotianae Breda, and would be the main cultures in high incidence area of zero leaf disease in sisal planting region.

A genus, Tolypanthus, and three species: Tolypanthus esquirolii (Lévl.) Lauener, Morus liboensis S. S. Chang and Scutellaria franchetiana Levl. from Fuyuan Shibalianshan Provincial Nature Reserve were reported as newly recorded species to Yunnan province. Voucher specimens for the reported species were preserved in the Herbarium of Kunming Institute of Botany (KUN), Chinese Academy of Sciences.

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.

The effects of long-term nutrient deficiency on cassava agronomic characters, yield and starch content were studied to provide scientific basis for fertilization of continuous cropping. In this study, experimental materials in 2019 to 2021 (continuous cropping in 28th-30th years) were selected from the time axis of long-term fertilization trials. CK (with NPK), –N (without N), –P (without P), –K (without K) combined with two cassava varieties SC205 and SC124 were selected. The SPAD value, plant height, stem diameter and starch content, yield, starch yield of the fresh storage root (FSR) were measured and evaluate. Compared to CK, –N and –K significantly reduced plant height, and –N, –P and –K significantly reduced stem diameter of cassava. Meanwhile, –K significantly reduced SPAD value of leaves. Test of between-subjects effect showed that, variety or fertilization had significant effects on agronomic characters, but the interaction effect between them was not significant. The starch content of FSR, compared to CK, –N significantly improved in 2021. –K significantly reduced, the three-year average decrease was 14.2%. Compared to CK, –N, –P and –K significantly reduced the yield, starch yield of FSR, storage root number per plant (SRNPP) and weight per storage root (WPSR). The yield of FSR reduced by more than 40.0% under different nutrient deficiency, while the yield effects were insignificantly different among nutrient deficiency treatments. The starch yield of FSR under -K decreased by 53.3%, the decrease was significantly higher than that of –N and –P. The correlation analysis showed that yield, starch yield of FSR were extremely significantly positively correlated with the SRNPP, and significantly positively correlated with the WPSR. –N, –P and –K significantly inhibited cassava growth. N was the primary limiting factor for cassava fresh storage root yield in the early stage of continuous cropping, followed by K, but P effect was not obvious. With the extension of continuous cropping years, the effects of K and P effect gradually became more significant, and N, K became the main limiting factors, then there was no significant difference on the fresh storage root yield effect among N, P and K, there were equally important.

Rubber tree is important in global rubber production. In order to reveal the effects of microelement fertilizer combined with absorption enhancer on the growth of rubber tree seedlings, and lay a foundation for the innovation of microelement fertilizer application technology of rubber tree. In this study, the single application of microelement (W), the combination of absorption enhancer formula 1 and microelement fertilizer (C₁+W), and the combination of absorption enhancer formula 1 and microelement fertilizer (C₂+W) were treated with ultra-pure water as the control to investigate the effects of compound microelement fertilizer application alone or combined with absorption enhancer on the growth, dry matter accumulation, photosynthesis, root development and nitrogen distribution of rubber tree seedlings and their mechanisms. The results showed that micronutrient fertilizer could increase the dry matter accumulation of roots, stems, and leaves in rubber seedlings, thereby increasing the individual fresh weight, dry weight, and dry to fresh ratio. Among them, C₂+W increased the fresh and dry weight of plants by 4.18 and 5.89 times, which is much greater than those of C₁+W and W. The accumulation of dry matter in rubber seedlings by microelements fertilizers was positively correlated with root length, root surface area, and root volume, and with chlorophyll content, transpiration rate, and net photosynthetic rate of rubber seedlings. The root development and photosynthesis were positively correlated with nitrogen accumulation in various organs of crops, soluble protein content, nitrate reductase activity (NR), glutamine synthase activity (GS), and glutamate dehydrogenase activity (GDH) in leaves. Notably, the single application of microelements fertilizer had no significant effect on NR activity, indicating that W had a weak effect on nitrogen assimilation in the reduction of nitric acid to nitrite. Significantly, the single application of microelements fertilizer (W) had no significant effect on NR activity, indicating that microelements fertilizer had a weak effect on nitrogen assimilation in the reduction of nitric acid to nitrite. In summary, microelements fertilizers and absorption enhancer enhance the connection between C assimilation and N metabolism processes in rubber seedlings, promote the growth and development of rubber seedlings. Considering the wide and thick leaves of rubber, tight cells, and thick stratum corneum, subsequent research should continue to screen more suitable absorption enhancer and optimize the combination with microelements.

In order to investigate the effects of intercropping Centrosema pubescens or Grona styracifolia on soil physicochemical properties, microbial community structure and diversity in the litchi orchard, soil samples from 0 to 40 cm depth between litchi tree rows were collected under intercropping with either C. pubescens or G. styracifolia. Physicochemical factors such as soil organic matter, total nitrogen, total phosphorus, total potassium, nitrate nitrogen, ammonium nitrogen, available phosphorus, available potassium and pH were measured. In addition, Illumina NovaSeq sequencing platform was used for 16S amplicon sequencing to analyze the microbial communities in the soil under intercropping with C. pubescens or G. styracifolia in the litchi orchard. The results showed that the nutrient content in the 0-20 cm soil layer was generally higher than that in the 20-40 cm soil layer. In the 0-20 cm soil layer, the C. pubescens intercropping treatment increased soil organic matter by 7.06%, total nitrogen by 8.70%, and ammonium nitrogen by 103.29%, compared to the control. In the intercropping treatment with G. styracifolia, soil ammonium nitrogen increased by 69.41%, nitrate nitrogen increased by 32.48%, available phosphorus increased by 112.78%, and available potassium increased by 9.44%, compared to the control. In the 20-40 cm soil layer, the C. pubescens intercropping treatment increased soil ammonium nitrogen by 114.58%, but decreased available potassium by 48.07%, compared to the control. In the intercropping treatment with G. styracifolia, soil nitrate nitrogen decreased by 15.07%, while available phosphorus increased by 105.43% and available potassium increased by 32.60%, compared to the control. In terms of microbial diversity, the indices in the 0-20 cm soil layer were generally higher than those in the 20-40 cm soil layer. In the 0-20 cm soil layer, the ACE index and Chao1 index in the C. pubescens intercropping treatment were decreased by 7.65% and 7.68%, respectively, compared to the control. In the 20-40 cm soil layer, the ACE index and Chao1 index in the intercropping treatment with G. styracifolia were increased by 6.93% and 6.74%, respectively, compared to the control. In terms of soil microbial community structure, the dominant phyla in all soil samples were Acidobacteria, Chloroflexi, Proteobacteria, Firmicutes, and Actinobacteria, while the dominant genera were Gp2, Gp13, Bryobacter, Candidatus Solibacter and Bathyarchaeia within the Acidobacteria phylum. After intercropping, the relative abundance of Thaumarchaeota, Nitrospirae, Verrucomicrobia, Gp2, Gp13 and Bryobacter increased. Redundancy analysis indicated that pH, total potassium, total phosphorus, and available potassium were the main physicochemical factors affecting soil microbial community structure. In summary, the results of this study would provide a theoretical basis for intercropping with C. pubescens or G. styracifolia in litchi orchards.

As an important component of terrestrial soil carbon reservoirs, the agricultural soil organic carbon pool is greatly influenced by cultivation patterns. Coffee, one of the major economic crops in tropical regions of the world, a minor changes of its cultivation pattern can significantly affect the carbon balance of terrestrial ecosystems. Mulching cultivation is one of the traditional cultivation models for coffee, but its impact on the organic carbon composition of coffee plantation soil is still unclear. Therefore, based on the previous research of our team using coffee peel and leaf litter as substitutes for traditional mulch to cultivate coffee, four mulching treatments were set up in this study: uncovered coffee waste (CK), coffee leaf litter mulch (L), coffee peel mulch (P), and both coffee peel and litter mulch (PL). Soil micro-environment, microbial community diversity and biomass, organic carbon fractions, and other indicators were monitored in the coffee plantation, and the intrinsic relationships between soil micro-environment, microbial community structure, and organic carbon fractions were analyzed to investigate the effects of coffee waste cover on soil components and the key driving factors. The results showed that coffee waste cover did not affect the content of soil organic carbon (SOC), heavy fraction organic carbon (HFOC), and dissolved organic carbon (DOC), while coffee peel and litter mulch significantly increased the content of soil light fraction organic carbon (LFOC) by 13.31% and 14.12%, respectively. Coffee waste mulch did not affect soil micro-environment indicators or microbial diversity. Coffee peel cover significantly increased soil microbial biomass by 14.05%, and increased the relative abundance of Proteobacteria and Firmicutes by 18.60% and 80.77%, respectively, while reducing the abundance of Cyanobacteria by 70.14%, but had little impact on soil fungal community. Coffee litter mulch significantly increased the relative abundance of Proteobacteria and Firmicutes by 14.43% and 57.63%, respectively, while reduced the abundance of Cyanobacteria by 73.43%, and significantly increased the relative abundance of dominant fungi Ascomycota by 14.79%. The reason why coffee waste mulch did not affect the soil organic carbon content is mainly attributable to the insensitivity response of HFOC content to coffee waste mulching. The increase of microbial biomass and the increase relative abundance of Firmicutes are the main reasons to enhance the excitation effect caused by external organic carbon input, thus significantly increasing the content of soil LFOC content. The short-term mulch of coffee waste significantly increased the content of soil LFOC content, which is contribute to improve the soil carbon storage of coffee plantations and optimize the green and low-carbon production mode of coffee.

Aquilaria sinensis (Lour.) Gilg is a resin containing wood in the genus Aquilaria or Gyrinops. Among them, agarwood essential oil (AEO) is the main functional active component of agarwood, which has good neuroprotective effect and is often used to soothe the body and mind, relieve anxiety and depression, and treat insomnia. A large number of studies have shown that the chemical composition of AEO mainly includes chromones, sesquiterpenoids, aromatics, fatty acids and other compounds, among which 2-(2-phenethyl) chromone and sesquiterpenoids are the characteristic components. However, there is no clear standard for AEO classification and quality testing, and the quality of AEO is uneven, which greatly affects the development of agarwood industry. The efficacy of AEO is closely related to its chemical composition. The chemical composition and content of AEO obtained from different raw materials (species, origin, induction methods and time) and different extraction methods (hydro-distillation, supercritical fluid carbon dioxide extraction, solvent extraction) are quite different. Therefore, it will be the direction of future research to establish a sound grading and quality testing standard of AEO, and reveal the internal relationships of the chemical composition of AEO with the raw materials and extraction methods. In addition, due to the increasing demand for agarwood, the wild population of agarwood species has declined rapidly, resulting in the depletion of wild resources. However, with the popularization of artificial cultivation and induction methods, the yield of agarwood has been greatly improved, which provides a research basis for further research on AEO. This article reviews the chemical components of AEO from different sources and their application prospects in neuroprotective effects, and analyzes the problems existing in the current research of AEO.

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.

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.

Dendrobium are famous for the ornamental and medicinal value. In order to explore the volatile components in the flowers of Dendrobium in Sect. Holochrysa and Sect. Chrysotoxae Kraenzl., the volatile components in the flowers of five Dendrobium in Sect. Holochrysa and seven Dendrobium in Sect. Chrysotoxae Kraenzl. were extracted by solid phase micro extraction (SPME) and analyzed via gas chromatography-mass spectrometry (GC-MS). Results showed that 74 volatile components were identified from the flowers of the species, 47 of which from D. hancockii in Sect. Holochrysa were the main volatile components; Secondly, there were 37 and 35 volatile components from D. chrysotoxum and D. harveyanum in the Sect. Chrysotoxae Kraenzl., respectively. The least component species was D. farmeri in the Sect. Chrysotoxae Kraenzl. with only 18 volatile components. Most of the species of volatile substances in Dendrobium were more than 20, and most of which were alkenes, except D. kenkinsii and D. densiflorum in the Sect. Chrysotoxae Kraenzl. mainly contained aldehydes. Cluster analysis of volatile ingredients showed that all the Dendrobium flowers were clustered together except a few Dendrobium plants were not clustered in the original grouping, which indicated that the volatile substances in Dendrobium flowers could be used as a reference for Dendrobium grouping. This study would provide references for the breeding, resource exploration and utilization of Dendrobium, and exert significant value on the grouping of Dendrobium.

Passion fruit (Passiflora edulis) is a characteristic and advantageous fruit in Guizhou, which is of great significance in poverty relief consolidation and the rural revitalization. However, in recent years, the viral diseases of passion fruit have become increasingly severe, leading to a sharp decline in yield and quality, which thereby seriously constrain industry development of passion fruit. In order to determine the virus species, distribution and compound infestation in the main plantation areas of passion fruit in Guizhou province, a total of 153 samples suspectedly infected by virus were collected from five main plantation orchards of passion fruit in five counties, i.e. Luodian, Congjiang, Rongjiang, Zhenning and Zhenfeng, and the virus detection was carried out by RT-PCR. The results showed that seven viruses were detected from the tested samples, namely East Asian Passiflora virus (EAPV), Telosma mosaic virus (TeMV), Cucumber mosaic virus (CMV), Turnip mosaic virus (TuMV), Passiflora mottle virus (PaMV), Passiflora latene carlavirus (PLV), and Potato virus Y (PVY), among which PVY infection was firstly reported from passion fruit. EAPV was the most prevalent one with infection rate as high as 96.08%, followed consecutively by TeMV (81.70%), CMV (78.43%), TuMV (44.44%), PaMV (26.80%), PVY (24.84%) and PLV (15.03%). In the present case, the distribution of passion fruit viruses in Guizhou province and the diversity of virus sequences were analyzed. Seven viruses were detected in Zhenning, six in Zhenfeng, five in Rongjiang and Congjiang, and three in Luodian. There’s a close identity between the nucleic acid of the seven detected viruses and the corresponding reference sequences (above 95%). Phylogenetic analysis revealed that EAPV, TeMV, PaMV, PLV and TuMV somewhat geographical clustered with passion fruit virus isolated from other provinces in China. CMV and PVY were most closely related to Cucumis melo CMV isolated from Spain and Capsicum annuum PVY isolated from Rwanda respectively, suggesting that the virus sequences diversely varies among the origins in China. A total of 24 types of mixed infection were detected in the main growing areas of passion fruit in Guizhou, and the complex infection rate was as high as 94.77%. The complex infection with 3-5 types predominated in the tested samples, and the combination of EAPV+TeMV+CMV was most frequent among the complex infections among which, EAPV, TeMV and CMV detected ranged from 78.43% to 96.08% in the five counties, somehow reflecting that they were the major viruses to prevent in passion fruit industry of Guizhou province. In addition, a multiplex PCR assay system for EAPV, TeMV and CMV was established in this study, which provides technical support for the rapid detection of related viruses.

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.

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.

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.