Gynostemma pentaphyllum is an important medicine-food homology plant. It enjoys the reputation of 'Southern ginseng' as it contains compounds of ginsenosides. As wild resources of G. pentaphyllum depleted gradually, artificial introduction and cultivation of G. pentaphyllum has become an inevitable trend. However, due to soil irrigation, fertilization, and pesticide use, problems such as unstable quality of medicinal materials and excessive heavy metal content in G. pentaphyllum occur from time to time, which seriously affects its standardized cultivation and the quality and safety of medicinal materials. Hydroponic production has the advantages of short cycle, high yield, no continuous cropping obstacles, and can effectively avoid heavy metal pollution, so it is widely used in the production of various Chinese medicinal materials. In this study, G. pentaphyllum seedlings were treated with different nutrient solution, temperature, light intensity and photoperiod. After that, growth characteristics and accumulation of total saponins of G. pentaphyllum were examined to obtain the most suitable hydroponics conditions, and thus provide reference and technical support for the large-scale production and organic cultivation of G. pentaphyllum. The results showed that Japanese Yamzaki formula with pH value 6.0 was the best nutrient solution for hydroponics of G. pentaphyllum. Correlation analysis showed that under different nutrient solution conditions, the total saponin content of single plant was highly positively correlated with plant height, leaf length, leaf width, number of leaves, fresh weight per plant and dry weight per plant, indicating that the cultivation of high-biomass plants was the key of the cultivation of high-quality plants of G. pentaphyllum. Under variable temperature of 20 to 30 ℃, photoperiod of 10 to 14 hours of light per day, and light intensity of 100 μmol/(m²·s), seedlings of G. pentaphyllum grew well and the total saponin content of the dry samples exceeded 3%, which was higher than the existing standards. This study would provide a scientific basis for the realization of double precise control of production and quality of G. pentaphyllum, and lay the foundation for the future research on large-scale production and quality standards of it.

Praxelis clematidea (Griseb.) is one of the most important invasive plants in China, which is continuously spreads with the increasingly serious nitrogen deposition in terrestrial ecosystem. The objective of the study was to reveal the responses of growth characteristics and accumulate the basic data for formulating corresponding prevention and control strategies using simulated nitrogen deposition. The growth characteristics such as root and plant length, leaf number and leaf area, root characteristics, biomass and its distribution and chlorophyll content in 45 days with four nitrogen deposition levels (control of 0, low nitrogen group of 40 kg/hm², medium nitrogen group of 60 kg/hm², high nitrogen group of 80 kg/hm²) compared with the 90 days were measured respectively. The results showed that the developmental ability was significantly improved in both growth periods (P<0.05) with the increase of nitrogen deposition level. Compared with N₀, the root length and plant height increased by 44.38% and 60.89% after N₃ culture for 90 days. The number of leaves and leaf area increased by 122.78% and 119.32%, and the growth rate of total root length, root surface area, root volume and root mean diameter was 56.04%, 42.36%, 59.38% and 61.54%. At 45 d, compared with the control group, total biomass of N₁, N₂ and N₃ increased by 37.50%, 81.25% and 106.25%, and the corresponding data at 90 d was 23.81%, 61.90% and 80.95%, respectively. Further comparison of the biomass distribution characteristics with different nitrogen concentrations at 45 d and 90 d showed that the different concentrations of nitrogen had inhibitory effects on RBR and R/S, and the inhibitory effect of low concentration nitrogen and early growth stage was stronger than that of high concentration nitrogen and late growth stage (P<0.05). However, it showed that a promoting effect on LBR and SBR was stronger under high-concentration nitrogen treatment and in the late growth stage of Stinkweed (P<0.05). When potted for 45 days, the content of chlorophyll a in the high nitrogen group (N₃) was increased by 131.69% compared with the control group (N₀), and the increase in chlorophyll b was 787.50%. Chlorophyll a and chlorophyll b increased by 82.45% and 314.29% respectively in potted plants for 90 days. It shows that the chlorophyll synthesis ability has strong tolerance to the heterogeneous environment represented by high nitrogen levels. At the early stage of growth (45 d), the positive feedback effect on moderate-level nitrogen deposition (N=60 kg/hm²) was strong. However, with the extension of the growth period (90 d), the adaptability to high levels of nitrogen deposition (N=80 kg/hm²) was significantly improved. The result proves that the aggravation of nitrogen deposition is beneficial to its growth.

Internal browning (IB) seriously restricts the development of pineapple industry. Its occurrence is mainly from excessive reactive oxygen species (ROS) causing membrane damage, which breaks the original compartmentalization between plastid polyphenol oxidase (PPO) and phenolic substrates in vacuoles. It polymerizes into quinones after contact with oxidation. The antioxidant clearance system is able to remove excess ROS and maintain the dynamic balance of ROS in the body. In early time, our laboratory used ascorbic acid (AsA) which can effectively delay the deterioration of IB of 'Pairs' pieapple. But the reaction mechanism of AsA is not clear. Ascorbate peroxidases (APX, EC1.1.11.1) are heme-binding enzymes that reduce hydrogen peroxide (H₂O₂) to water using AsA as an electron donor. It is involved in various developmental physiological processes and stress responses in plants. In this study, we selected six APX genes with AsA as the substrate in pineapple to analyze the occurrence process and the ascorbate transcript level changes after the AsA treatment. AcAPX1 was significantly upregulated at 9 d and 12 d after AsA treatment and was significantly different from the control group. It showed that AsA significantly enhanced the AcAPX1 expression. Correlation analysis showed that the incidence index of black heart disease was significantly positively correlated with the AcAPX1 expression level. It is speculated that this gene may play an important role in AsA delaying IB with pineapple. To further explore the mechanism of action, AcAPX1 was cloned from the pineapple pulp. The physicochemical properties and protein domain were analyzed by bioinformatics analysis. The results showed that the open reading frame length was 753 bp, encoding 250 amino acids. The predicted molecular weight of the protein was 27.410 87 kDa, and the theoretical isoelectric point was 5.52. There was no transmembrane helix region, which was a stable hydrophilic protein. Amino acid sequence alignment analysis showed that AcAPX1 of pineapple shared more than 85% homology with papaya, banana, coconut and oil palm. The functional domain analysis of AcAPX1 showed that it had heme binding sites, K⁺ binding sites and substrate binding sites (superfamily: cl00196), belonging to the members of the plant peroxidase superfamily. Cloning of AcAPX1 is of great significance for studying the molecular mechanism of its antioxidant capacity in pineapple and the control of internal browning. This study would lay a foundation for further exploring the molecular mechanism of pineapple AcAPX1 involved in AsA clearing ROS and delaying the deterioration of internal browning.

Thielaviopsis paradoxa is harmful to almost all palm plants, among which stem bleeding of coconut is the most serious, and no effective and safe control method is available. Among the biocontrol bacteria screened in the early stage of this study, Pseudomonas aeruginosa wrj-2-5 and Alcaligenes faecalis brj-21 were proved to have biocontrol potential against T. paradoxa. In order to determine the specific inhibitory effect of P. aeruginosa and A. faecalis on T. paradoxa, T. paradoxa was used as the target strain to determine the bacteriostatic effect, indoor control effect and fermentation conditions of the biocontrol strains wrj-2-5 and brj-21. The results showed that wrj-2-5 and brj-21 both had a bacteriostatic rate of more than 70% against T. paradoxa. In vitro experiment found that the two bacteria still had good bacteriostasis. The lesion area of the treatment group was significantly smaller than that of the control group. Earlier inoculation would lead to better effect. In addition, the strains had strong inhibitory effect on other pathogenic bacteria of coconut leaf spot, fruit rot, gray spot and heart rot. The optimal fermentation condition of wrj-2-5 was rotation speed 180 r/min, temperature 28 ℃, culture time 36 h, initial pH value 6.0-8.0, and inoculum amount 8%. The optimal fermentation condition of strain brj-21 was inoculum amount 8%, the initial pH value 6.0-8.0, rotation speed 180 r/min, temperature 28-32 ℃, and incubation time 24 h. In conclusion, wrj-2-5 and brj-21 have good control effects on the stem bleeding of coconut and fruit rot of coconut caused by T. paradoxa. They also have a certain inhibitory effect on the pathogens of other coconut diseases, which would provide an important reference for the green and biological control of T. paradoxa.

To select suitable slow-release fertilizers for sugarcane productions the endophytic bacterial community structure in the stems of sugarcane under different slow-release fertilizer applications were analyzed. Based on high-throughput sequencing techniques, the endophytic bacterial community structure in the stems of sugarcanes among conventional fertilization (CK) and different slow-release fertilizers (A-F treatments) were analyzed. In comparison with CK, the diversity of the endophytic bacteria in the stems of sugarcanes was significantly increased by adding long- acting agent (235 g/t) and synergist (3 g/t and 18 g/t), but the richness of the endophytic bacteria in the stems of sugarcanes was not significantly improved by slow-release fertilizer applications except adding long-acting agent (235 g/t) treatment C. Meanwhile, Herbaspirillum was the specific endophytic dominant bacterial genus in CK. Sporocytophaga and Cellvibrio were the unique endophytic dominant bacterial genera in the slow-release fertilizer adding long-acting agent (125 g/t) treatment A. However, no specific endophytic dominant bacterial genera could be found in the slow-release fertilizer adding long-acting agent (150 g/t) treatment B. Norank_f__SC-I-84, norank_f__Neisseriaceae, norank_f__JG30-KF-AS9 and Massilia were the specific endophytic dominant bacterial genera in the slow-release fertilizer adding long-acting agent (235 g/t) treatment C. Brevundimonas, Enterobacter, Staphylococcus were the unique endophytic dominant bacterial genera in the slow-release fertilizer adding synergist (3 g/t) treatment D. Cloacibacterium was the specific endophytic dominant bacterial genus in the slow-release fertilizer adding synergist (8 g/t) treatment E. And unclassified_f__Burkholderiaceae, Paenibacillus, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Corynebacterium_1, Chryseobacterium were the specific endophytic dominant bacterial genera in the slow-release fertilizer of adding synergist (18 g/t) treatment F. Furthermore, the functions of the endophytic bacteria in the stems of sugarcanes did not show significantly different between CK and applications of slow-release fertilizer treatments. In comparison with CK, the diversity of the endophytic bacteria in the stems of sugarcanes was significantly increased by adding longacting agent (235 g/t) and synergist (3 g/t and 18 g/t), but the richness only could be significantly improved by application with slow-release fertilizer adding with long-acting agent (235 g/t) treatment C. Except of slow-release fertilizers +long-term agent (150 g/t) treatment B, specific endophytic bacterial genera in the stems of sugarcanes all could be detected under slow-release fertilizer applications. Although the whole functions of the endophytic bacteria in the stems of sugarcanes were not significantly altered by slow-release fertilizer applications, higher stress resistant abilities could be concluded in sugarcanes under most of slow-release fertilizer applications (B-F treatments). Among them, the highest promotion and stress resistant effect on sugarcanes growth was the slow-release fertilizer + 235 g/t long-acting agent treatment (C) according to the composition and function of endophytic bacteria in stems of sugarcanes.

Low-ammonia concentrated natural rubber latex (CNRL) can alleviate the ammonia contamination problem caused by high-ammonia CNRL to a certain extent, and is gaining wider and wider application in a variety of CNRL products. In this study, four CNRL preservatives, BCT-2, HY, HM and LS, were used to prepare low ammonia CNRL, and the differences between the performances of low ammonia CNRL in different preserved systems were investigated by comparison with high ammonia CNRL. The results showed that the four preservation systems had good effect on the preservation of low ammonia CNRL, and all of them could meet the requirements of GB/T 8289—2016 national standard. Among them, the low ammonia CNRL preserved by BCT-2 had the lowest volatile fatty acid value (VFA No.), but the viscosity value was the highest, the lowest mechanical stability (MST); in addition, the average particle size of rubber particles was higher; the thermal stability and zinc oxide mechanical stability (ZST) were lower; the dry rubber film strength was higher. The low ammonia CNRL preserved by HY had the lowest VFA No., the lowest viscosity, highest MST and thermal stability; the fastest pre-cure speed; pre-cure latex with the lowest viscosity, highest MST and thermal stability; higher strength of vulcanized rubber film. HM preserved low ammonia CNRL with lower viscosity; higher MST and good stability; the lowest dry rubber film strength; the slowest pre-cure speed. LS preserved low ammonia CNRL with higher VFA No. and higher viscosity value; lower MST and poor stability; the smallest rubber particle size; the highest concentrated latex dry rubber film and vulcanized rubber film strength; the best dry rubber film thermal stability. Contrast analysis showed that HY and LS saved better overall performance of low ammonia CNRL, where HY low ammonia CNRL was suitable for the production of foam products, adhesives, etc., while LS low ammonia CNRL was suitable for the production of gloves, balloons and other pure rubber impregnated products.

The trunks of ten-year-old Aquilaria sinensis trees were filled with high-pressure nitrogen gas and treated every 7 and 15 days for 3 consecutive months. The wood discoloration area was observed and measured, the content of alcohol-soluble substances was detected, and the chemical composition and relative content of the agarwood were analyzed by GC-MS at 7 and 10 months after treatment. The effect of nitrogen gas filled on the agarwood formation was discussed, which would provide a feasible induction method for artificial agarwood formation. The results showed that nitrogen treatment significantly increased the longitudinal discoloration length and transverse discoloration width of wood trunks, and the results of the treatment filled with nitrogen gas every 7 days (N₇) were better than that of the treatment filled with nitrogen every 15 days (N₁₅). Ten months after N₇ treatment, the discoloration area was the largest, and the length of agarwood zone and total discoloration zone in both longitudinal and transverse direction were significantly longer than those of N₁₅ and CK₁. Inflating nitrogen treatment could significantly increase the content of alcohol-soluble substances and agarotetrol, and the content of agarwood zone was higher than that of transition zone. The content of alcohol-soluble substances and agarotetrol in agarwood area increased by 14.04% and 28.47% compared with that of N₁₅ and CK₁, respectively, and the content of agarotetrol was 0.12%, which significantly higher than that of N₁5 and CK₁, seven months after N₇ treatment. The content of alcohol-soluble substances and agarotetrol in each treatment increased with the increase of treatment time. Ten months after N₇ treatment, the content of alcohol-soluble substances and agarotetrol in agarwood zone was 19.37% and 0.30% respectively, which was noticeably higher than that of N₁₅ and CK₁. The content of alcohol-soluble substances and agarotetrol in N₁₅ treatment increased by 9.42% and 51.50% respectively, compared with CK₁. The volatile component of agarwood in N₇ treatment was the highest, which was rich in 25 terpenes, 5 chromones and 8 other compounds, and the total relative content of terpenes and chromones reached 66.09%, significantly higher than that of N₁₅ and CK₁.

In this paper, three types of green coffee oil microcapsules were prepared by complex coacervation using the combination of gum arabic (GA) with soybean isolate protein (SPI), whey isolate protein (WPI) and sodium caseinate (SC) as wall materials, respectively. The turbidity, infrared spectral characteristics, apparent morphology and fluorescence co-localization of the wall materials were analyzed by combining different characterization techniques; the encapsulation efficiency, morphology, particle size, structural characterization and thermal stability of the three green coffee oil microcapsules were compared. Gum arabic and different proteins formed complexes through electrostatic interactions, which can be used as a new wall material for encapsulating green coffee oil. Infrared spectral analysis showed that the three wall materials could encapsulate green coffee oil better. The encapsulation rate in a descending order was SPIGA-GCO (69.26%), SCGA-GCO (58.69%), WPIGA-GCO (52.57%). The microstructure of green coffee oil microcapsules had a flat surface without obvious cracks, among which the oil droplets were more uniformly distributed in SPIGA-GCO. DSC analysis showed that the thermal denaturation temperature of microcapsules was higher (103.93-108.33 ℃), with good thermal stability. The results showed that the performance of SPIGA-GCO microcapsules was significantly better than the microcapsule products prepared from the other two wall materials. This study would provide technical support for the development of stable and effective green coffee oil microencapsulated products, and also provide a theoretical basis for the high value utilization of green coffee oil.

Single nucleotide polymorphism (SNP) is widely distributed in plant genomes, which is one of the most abundant form of DNA variation. The molecular markers based on single nucleotide polymorphism are considered to be of great application prospect. Penta-primer amplification re-fractory mutation system (PARMS) is a kind of new genotyping system based on single nucleotide polymorphism (SNP) which has the advantages of high throughput, high accuracy, low cost and short time consuming. The establishment of the PARMS system of pineapple is significant in germplasm identification, gene mapping and marker-assisted selection of pineapple. In this study, three germplasms of significant difference in phenotypes were used as the materials. A specific primer SNP31 was designed based on the resequencing data of 130 germplasm resources. The result revealed SNP31 could effectively group the pineapple germplasm resources, and be used for the subsequent optimization of the system. Reaction volume,primer concentration, method of DNA extracting and template DNA amount were optimized. The results showed that reaction volume, primer concentration and template DNA amount could affect the fluorescence signal value of the genotype signal point. The fluorescence signal value of genotypic signal point decreased when the reaction volume was larger or smaller. The optimal reaction volume was 6 μL. When the concentration of primer and template DNA increased, the fluorescence signal value of genotype signal point increased. The optimal concentration of primer and template DNA was 100 μmol/L and 25 ng/μL, respectively. In addition, different methods of genomic DNA extraction could group well the PARMS-SNP for the three germplasms of pineapple. The optimal PARMS reaction system was as follows:total volume 6 μL, containing 1 μL template DNA (25 ng), 3 μL PARMS mix (2×), 0.45 μL primer mix (100 μmol/L) and 1.55 μL ddH₂O. With the optimal PARMS reaction system, high quality results of PARMS-SNP genotyping was produced on sixty-five pineapple germplasm resources, which indicated that the reaction system was accurate and stable. The establishment of the optimized PARMS genotyping system could provide a basis for the genetic diversity analysis, genetic linkage map construction, gene mapping and marker-assisted selection of pineapple in this study.

Pokkah boeng disease (PBD) caused by Fusarium complex is one of the major diseases in sugarcane with great impact on the sugarcane industry worldwide. F. sacchari is the prevalent species responsible for PBD in Guangxi. Albeit of a long history of study on the disease, the mechanisms underlying the pathogenicity of the pathogen are still far from clear. To tackle this challenge, we generated an insertional mutant library by transformation of the conidial spores from F. sacchari strain FF001 via Agrobacterium tumefaciens-mediated transformation (ATMT). A total of 3018 hygromycin B-resistant transformants were obtained. Among 12 transformants randomly selected, nine out of 12 transformants carried a single copy of T-DNA, as verified by PCR and Southern blot analysis. The mutants were further screened for virulence variation on detached leaves and 30 mutants with obvious changes in virulence were obtained, including 21 mutants with significantly attenuated and 9 mutants with enhanced virulence. The sites of insertion were determined by thermal asymmetric interlaced PCR (TAIL-PCR) and sequence alignment to the genome sequence of F. sacchari. The majority of the insertions were found in coding regions or promotor regions, with a few in terminator or intergenic regions. It was observed that a few insertions were accompanied with genome fragment deletion, resulting in more than one genes being disrupted in a single insertion. Among the 22 mutated genes with annotated functions were those encoding alpha-mannosidase, neutral amino acid permease, oligomeric Golgi complex component 4, oligopeptide transporter 2, acyl-CoA dehydrogenase, acetoacetyl-CoA synthetase, carbonic anhydrase, Bud 10 protein, kinesin-related protein bimC, zinc finger protein ASD 4, transcription initiation factor TFIID, cutinase G-box binding protein, acriflavine sensitivity control protein ACR-2, nuclear VCP-like protein, heat shock protein 30, thioredoxin, type 2C protein phosphatase (PP2C), exoribonuclease, selenoprotein, DNA polymerase eta, survival factor 1, and aldehyde dehydrogenase, several of which, such as zinc finger protein ASD4 in Magnaporthe oryzae, cutinase G-box binding protein in Ustilaginoidea virens, oligopeptide transporter in Colletotrichum gloeosporioides, PP2C in Fusarium oxysporum, have been implicated as pathogenicity genes. The availability of the diversified pathogenic mutants lay a new foundation for further study on the molecular pathogenic mechanisms of F. sacchari.