Latest ArticlesTo gain insight into the genetic diversity and relationship of the tropic bioenergy plant physic nut (Jatropha curcas L.) in Yunnan, China, joint analysis of agronomic and molecular characters was performed in the present study, using different accessions collected from nine sources/geographical provenances in Yunnan. To investigate the population polymorphism, eight pairs of SSR molecular markers were developed by MISA program, and four of them with higher polymorphism were selected for PCR amplification using 95 DNA samples collected from nine populations. The results indicated that JC01 exhibited the best polymorphism (0.711). UPGMA clustering analysis suggested that Baoshan and Xishuangbanna might serve as the parents or origins of physic nut in Yunnan, which was partially related to the geographical origin of populations. Comprehensive investigations revealed among all examined biological traits of seeds or seedlings, the underground fresh weight (UFW) exhibited the highest coefficient of variation, with obvious separation among populations. Two individual seedlings with extreme variance in UFW (BNMH and CXYM) were selected for RAD-based genomic sequencing, while 2783 and 3033 contigs were assembled. Analysis of genome assembly data using GenomeScope revealed that both materials were diploid, and a total 22 756 valid SNPs were detected at the whole genome level using genome-wide association study (GWAS). High frequency-SNPs associated with UFW preferably located on LG9, and three candidate proteins were linked to the UFW trait. The results indicated that the physic nut germplasm collected from different regions of Yunnan exhibited a high level of genetic diversity and uniqueness, which should facilitate further studies on its molecular breeding.
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.
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.
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.
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.
Sugarcane is an important sugar crop and energy crop. Evaluating the nutritional quality of sugarcane germplasm resources can systematically understand the nutritional value of sugarcane germplasm resources, and provide scientific basis for the development and utilization of sugarcane germplasm resources and breeding of new varieties. We carried out a study using 100 sugarcane germplasms, analyzed 14 nutritional indexes such as sucrose, reducing sugar, total free amino acid, polyphenol, mineral and protein in sugarcane juice, SPSS software was used for Principal Component Analysis (PCA) and Systematic Cluster Analysis (SCA) of nutritional quality traits. Results showed that there were differences in nutritional components among the 100 sugarcane germplasms and some nutrients had a significant correlation with each other. Sucrose content was negatively correlated with reducing sugar, protein, total free amino acid, fructose and glucose content, while protein content was positively correlated with total free amino acid and total polyphenol content. The content of fructose, glucose and sucrose was positively correlated with the content of P. Among mineral elements, Ca content and Fe content, Fe content and Cu content were positively correlated. The main factors affecting the nutritional quality of sugarcane germplasm were reducing sugar factor, protein factor, sucrose factor, Ca content factor and K content factor. The cumulative variance contribution rate of the common factors to comprehensive evaluation of sugarcane nutritional quality was 69.62%. SCA showed that the nutritional quality of the 100 sugarcane germplasms could be divided into 5 groups (European distance D=18.5). Group Ⅰcontained 77 resources, which had the highest sucrose content. Group Ⅱ contained 6 resources with higher Ca and Fe content. Group Ⅲ contained 2 resources, the average content of reducing sugar, protein, total free amino acid, total polyphenol, fructose, glucose, P, Na was high, and the average sucrose content and Fe content were low. Group Ⅳ contained 4 resources, which had the highest average total free amino acid content, higher average protein and total polyphenol content. Group Ⅴcontained 11 resources, with the highest average K content. The comprehensive evaluation of nutritional quality of the 100 sugarcane germplasms showed that the top 5 sugarcane varieties were 'Hetang 1', 'Dezhe 0978', 'Funong 40-95', 'Zhongzhe 45' and 'Yunzhe 06-193'.
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.
In order to objectively select new rubber tree clones suitable for China's rubber planting environment, the yield and secondary characters of four introduced clones 'Reshi 09-5' 'Reshi 09-6' 'Reshi 09-7' and 'Reshi 09-10' were systematically identified and evaluated. The results showed that among the four clones, just 'Reshi 09-7' showed fast-growing, not yet in yield. Only 'Reshi 09-5' was close to the control in the first taping year and was lower in other years. The results of latex physiological characteristics showed that, according to good latex stability, fast latex discharge and high sugar utilization rate, 'Reshi 09-5' showed good rubber production potential, had higher thiol content and lower sucrose content than that of 'RRIM600', and there was no significant difference in dry rubber yield and initial speed of latex discharge between them. 'Reshi 09-6' had higher dry rubber content and plugging index, thicker original bark and more latex tubes number than 'RRIM600', and there was no significantly differences in initial flow rate and sucrose content between them. It was considered that the variety had good rubber production potential, but the metabolic intensity of latex was low. It had better potential in latex production, but a low metabolic intensity, so the production could be increased by stimulated tapping. The results of raw rubber properties, physical and mechanical properties, molecular weight and molecular weight distribution of vulcanizates of different varieties showed that there were some differences among the four clones. 'Reshi 09-5' showed the lowest in plastic initial value and Mooney viscosity, but the highest plastic retention rate. 'Reshi 09-6' showed the highest Mooney viscosity. According to larger weight-average molecular weight, 'Reshi 09-7' showed good physical and mechanical properties. In terms of stress resistance performance, 'Reshi 09-5' had the lowest wind damage collapse rate and 'Reshi 09-10' had the highest. The results of cold-resistant outpost data showed that under the condition of no cold injury in the control clone '93-114', the cold injury grade of 'Reshi 09-5' was 1.00, and that of 'Reshi 09-7' was 0.17. The comprehensive analysis results showed that the fast-growing traits of the four introduced clones were obvious. 'Reshi 09-6' had good rubber production potential. 'Reshi 09-5' had better wind resistance than 'RRIM600', 'Reshi 09-7' had good adaptability in cold damage. Among the four clones, 'Reshi 09-6' showed better performance in yield, girth growth, latex physiological characteristics and latex quality, and suitable to popularize and cultivate in same condition.
Sugarcane is an important sugar crop in the world, but the main sugarcane producing areas in China are hilly and dry slopes, and seasonal droughts occur frequently due to the uneven distribution of rainfall. Droughts do great harm to yield and quality and the sustainable development of sugarcane industry in China. The plant hormone abscisic acid (ABA) not only regulates plant growth and development, but also plays an important role in the physiological and biochemical responses of plants environmental stresses. In this study, we used sugarcane (Saccharum officinarum L.) variety 'Guitang 42' as the material to investigate the effects of exogenous ABA on leaf physiological characteristics and gene expressions under water stress condition in treatments control (normal irrigation), control+ABA, drought (stop irrigation), drought+ABA. The foliar application of 15 μmol/L ABA was sprayed twice in two days before drought stress given. The results showed that the changes of main physiological and biochemical parameters and gene expression in control+ABA treatment were not significantly different from those of the control. The leaf relative water content (RWC) was gradually decreased by drought treatment but it could maintain higher in drought+ABA treatment. The drought treatment could result in an increase in malondialdehyde (MDA) and hydrogen peroxide (H2O2) content, but the plants applied with ABA were found to resist the excessive accumulation of MDA. Drought stress significantly reduced the leaf chlorophyll content in sugarcane, but the exogenous ABA application decreased the degradation of chlorophyll, counteracted, at least in part, the decrease in quantum efficiency of PSII (ΦPSII). The expression of gene encoding 9-cis-epoxycarotenoid dioxygenase (NCED) for ABA biosynthesis, the genes encoding Δ1-pyrroline-5-carboxylate synthase (P5CS) for proline biosynthesis, and the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD) encoding genes was significantly increased in the leaf under water stress condition, following the significantly higher endogenous ABA content, proline content and CAT, SOD, APX and POD activities in water stress treatment as compared to the control. But exogenous ABA application under water stress could further enhance the expression of the genes, hence further improved the ABA content, proline content and related antioxidant enzyme activity. The results clearly suggests that the foliar ABA application could triggering the over expression of antioxidative defense system, and improve drought tolerance of sugarcane under water stress condition.
Identification of heterozygote is a key step in the cross breeding of Lentinula edodes. A new ISSR technique (N-ISSR) was designed in this study based on discrimination between the two nucleus of the donor strain to identify quickly and accurately the authenticity of hybrid strains of L. edodes. The new ISSR was used to identify 40 hybrid strains which were from the Di-mon mating between dikaryon wild strain YX7 and spore monokaryons of cultivated strain 808, as well as microscopy observation combined with antagonistic test (MOCAT) and the traditional ISSR technique (T-ISSR) as the control. N-ISSR results showed 27 strains were confirmed to be true heterozygote as they possessed specific DNA bands from one of the nucleus of donor strain YX7, and the other 13 strains were confirmed to not be heterozygote. Among them, 11 strains were strain YX7 itself as they possessed both specific DNA bands from the two nucleus of strain YX7, and 2 strains were spore monocaryons of strain 808 as they had no any specific DNA bands of donor strain YX7. Compared with MOCAT, N-ISSR could thorough identify all the 27 heterozygote strains, which included the 19 strains identified as heterozygote, the 6 strains unable to be identified and 2 strains incorrectly identified as non-heterozygote by MOCAT. N-ISSR could identify all the 27 heterozyote stains and 13 non-heterozyote stains with simple primer, and could classify the heterozygote strains into two groups according to the type of nucleus received from the donor. On contrast, T-ISSR needed 4 primers to identify all the 27 heterozygote strains, and was unable to con firm the other 13 stains as non-heterozygote stains, and was unable to classify the heterozygote strains into two groups. In conclusion, N-ISSR was an effective tool to be used for fast, extensive and accurate identification of heterozygote and non-heterozygote strains of L. edodes, and would be a technical support for further study on the cross breeding and genetic analysis of L. edodes.