Abstract:Aluminum (Al) toxicity in acid soil,has become a worldwide topic,and boron (B) has been widely studied in alleviating Al toxicity. In order to explore the mitigation effect of B on Al toxicity in plants more clearly.This review mainly interpreted the mechanisms of Al tolerance in plants and the specific mitigation mechanisms of B on Al toxicity from two aspects:external and internal tolerance mechanism,and exploring the mitigation mechanisms of B on Al toxicity in plants,which mainly include:(1) inducing the secretion of organic acids; (2) regulating the change of root pH; (3) reducing the Al binding site on cell wall; (4) regulating the antioxidant system; (5) promoting vacuole chamber,in order to provide a theoretical basis for the B fertilizer application in acid soil to improve the Al tolerance of plants.

Abstract:A simple,fast and efficient method of constructing dual-target CRISPR/Cas9 vector was established based on the Golden Gate ligation. The two designed small target DNA fragments and one exogenous fragment were constructed together into the CRISPR/Cas9 vector with T4 DNA ligase. 20 dual-target CRISPR/Cas9 vectors against 10 reported rice genes were constructed with this method,and the positive rate was 100% with no mutation in sequences. This vector system provides an easy,rapid and efficient method for constructing dual-target CRISPR/Cas9 vector for rice. It also provides a reference for the construction of dual-target CRISPR/Cas9 vectors in other plants.

Abstract:Field and pot experiments were conducted in 2018 to compare the changes in indicators of nine mid-season hybrid rice varieties including average growth period,yields,average light energy production efficiency,average cumulative temperature production efficiency,ratooning ability,greenhouse gas emissions and heat tolerance during flowering period. The membership function method was used to comprehensively evaluate the adaptability of the tested varieties in the climate warming and ratooning ability in the middle and lower reaches of the Yangtze River. The results showed that there were obvious variations in the seven agronomic and ecological traits. According to the average values of subordinate functions,four mid-season hybrid rice varieties with moderate growth periods,high yields,high light and temperature production efficiencies,low greenhouse gas emissions,strong heat tolerances at flowering stage and good ratooning abilities were selected:C Liangyou Huazhan,Liangyou 6326,C Quanyou Huazhan and Longliangyou 3188. Liangyou 6326,C Liangyou Huazhan and Quanyou Huazhan are suitable for cultivating as ratooning rice with good potential popularization value in the middle and lower reaches of the Yangtze River. However,Longliangyou 3188 with high yield,strong heat resistance and the growth duration of 140 days should be sowed early as ratooning rice. Large-scale cultivating these four varieties selected as ratooning rice will mitigate the adverse effects of rice production on climate warming in the middle and lower reaches of the Yangtze River.

Abstract:Gossypium barbadense/G. hirsutum grafted cotton seedlings (S/R) were obtained by using G. hirsutum cotton Pima90 (R) resistant to Verticillium wilt as the rootstock and G. barbadense cotton variety Emian 22 (S) susceptible to Verticillium wilt in Hubei Province as scion. The disease resistance after incubation of Pima90 (R),Emian 22(S) and grafted cotton seedlings (S/R) was studied. H2O2 content in leaves was determined. The differences in the levels of POD/PAL enzyme activity and the expression patterns of PAL/GST genes were compared. Results showed that wilting degree of the G. barbadense/G. hirsutum grafted cotton (S/R) after the incubation of damaged cotton root with pathogen suspensions was between that of the rootstock Pima90（R）and scion Emian 22 (S),indicating that grafting improved the resistance of cotton seedlings to Verticillium wilt. H2O2 contents in leaves and the enzymatic activities of POD and PAL in Emian 22 (S),Pima90(R) and the grafted cotton (S/R) were obviously increased after incubation with Verticillium dahliae Kleb. However,H2O2 content in leaves,POD and PAL activities increased slowly in Emian 22 (S),rapidly in Pima90 (R),and moderately in the S/R grafted cotton. Pima90(R) and the grafted cotton (S/R) showed similar tendency of changing. Results of real-time PCR showed that the mRNA expression level of GST gene in three cottons increased firstly and then decreased. The duration of GST gene expression for Emian 22 (S),Pima90 (R) and grafted cotton (S/R) was 8-16 h and 8-48 h,respectively. The patterns of PAL gene expression in the three cottons were similar. Expression level of PAL gene was increased firstly,then decreased,and increased subsequently,with twice peak at 8 h and 48 h. The peak value in Emian 22 (S),Pima90(R) and grafted cotton (S/R) was low,high,and moderate.

Abstract:Citrus melanose,caused by Diaporthe citri,is a serious disease in citrus producing area. Previous reserches mainly focuses on the epidemic and prevention of citrus melanose in spring and autumn. However,Lane Late navel orange matures in late March. In order to explore the dynamics of melanose in winter and provide technical guide for the production of Lane Late navel orange,the occurrence of melanose from December 2017 to April 2018 in two orchards located in Guojiaba Village,Zigui County,Yichang City,Hubei Province was investigated. The results show that there was no significant increase in the number of lesions on the fruit surface and disease index in the two orchards during winter. The average temperature was under 15℃ with adequate rain and snow during this period. Further studies demonstrated that low temperature restricts the mycelial growth,conidioma formation,conidiation,spore germination and infection of the host of D. citri strain ZGDC50. The results suggest that low temperature may be one of the main factors to prevent the occurrence of melanose in Yichang during winter.

Abstract:In order to explore phenotypic and genetic variability among Botrytis cinerea population isolated from ginseng,154 B. cinerea strains that were pathogenic to ginseng,were isolated from eight regions in the main producing areas of ginseng in China. Phenotype was observed on potato dextrose agar for 3 weeks,transposable elements (TEs) and MAT locus were identified by PCR amplification,and pathogenicity of strains with different TEs was determined. Eight phenotypes,3 TEs types of Boty,Flipper and Transposa,and no Vacuma type were identified,of which Transposa was the highest proportion (93.51%) and the most pathogenic. Meanwhile,73 and 75 isolates were MAT1-1 and MAT1-2 types,respectively,which were found to be balanced overall in the population. The results obtained in the present study suggest a relatively uniform species diversity,rich phenotypic and genetic differentiation within the B. cinerea population from ginseng in China.

Abstract:Illumina sequencing technology was used to construct the cDNA library of two Sporisorium scitamineum strains Ss16 (strong pathogenicity) and Ss47 (weak pathogenicity),followed by transcriptome sequencing,and bioinformatics analysis after quality control in order to investigate the differences at transcriptional level between S. scitamineum strains with different pathogenicity and discover pathogenicity-related genes. The results showed that a total of 8.31G（Ss16）and 9.88G（Ss47） clean reads were obtained. There were 649 differentially expressed genes (DEGs) including 299 up-regulated genes and 350 down-regulated genes between Ss16 and Ss47. Results of GO annotation and KEGG pathway enrichment analyses showed that DEGs were significantly enriched in KEGG pathways involved in starch and sucrose metabolism,ABC transporters,degradation of aromatic compounds,metabolic pathways,purine metabolism. These pathways are mostly related to protein biosynthesis,transport and metabolism of substances. It will provide molecular basis for revealing the pathogenic mechanism of S. scitamineum.

Abstract:The spatial distribution and ecological risk assessment of bisphenol A (BPA) and bisphenol S (BPS) in surface sediment of Liangzi Lake were investigated. The results showed that BPS was detected only in sediment from the outlet of Liangzi Lake during the level period,with the concentration of 0.02 ng/g. The detection rate and concentration of BPA are obviously different from that of BPS. The detection rate of BPA was 100% during dry season,plain season and flood season. The concentrations of BPA ranged from 0.08 to 2.11 ng/g,and the maximum appeared in the center of East-Liangzi Lake. There was a significant positive correlation between the content of BPA and TOC. Compared with results of other studies at home and abroad,the concentration of BPA and BPS in surface sediments of Liangzi Lake was overall lower. The quotient method was used to evaluate the ecological risk of BPA in the surface sediments of Liangzi Lake. The results indicated that the concentrations of BPA in sediments from Liangzi Lake did not reach the level of risk to the ecological environment.

Abstract:MIL-53 (Al) was synthesized by solvothermal method, and TiO2/MIL-53 (Al) photocatalyst was prepared by using TiO2 as the carrier for the catalytic degradation of methine blue in sewage. The photocatalytic performance of the TiO2/MIL-53(Al) and the TiO2/Al2O3 was compared. The catalysts were characterized by thermogravimetric-differential scanning calorimeter (TG-DSC), Fourier transform infrared(FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and N2 adsorption-desorption. The photodegradation efficiency of submethyl blue was analyzed by photometric absorption method. The results showed that the degradation rate of methylene was more than 98.6% on TiO2/MIL-53(Al) photocatalyst, but that of methylene was only 70.3% on TiO2/Al2O3 photocatalyst. Therefore, the photocatalytic activity of TiO2/MIL-53(Al) photocatalyst exhibited much higher than that of the TiO2/Al2O3 photocatalyst in degradating methyl blue.

Abstract:A total of 546 Carassius auratus gibelio were collected from the lower reaches of the main stream of Irtysh River in China from April to October,2013. The food composition,feeding intensity and spatiotemporal variation,and feeding strategy of C. auratus gibelio were systematically analyzed and studied. The statistical results indicated that the overall jejunum rate of C. auratus gibelio was 28.17%,and the rates of jejunum before breeding season (May,54.7%) were significantly higher than those in other months. For food occurrence rate,Bacillariophyta (100%),and Chironomus larvae (86.67%) were common in the food composition of C. auratus gibelio. The weight percentage (61.52%),dominance index (62.36%),and Amundsen figure indicated that the plant debris were the most important prey of C. auratus gibelio. In addition,the food composition of C. auratus gibelio showed significant differences amomg different seasons (P＜0.05),whereas showed no significant difference among different length groups (P＞0.05). These results showed that C. auratus gibelio in Irtysh River is omnivorous and partial to phytophagy.

Abstract:DDM-BSA composite nanomaterial was synthesized by using BSA,2,4-dihydroxyphenyl,2,6-dimethylphenyl and methanone (DDM) (loaded drug) as raw materials through desolvation method. The prepared composite nanomaterial was characterized by ultraviolet-visible (UV-vis) spectrometer,transmission electron microscope (TEM),laser particle size analyzer et al. The results showed that the composite nanoparticles were uniformly dispersed with an average particle size of 49.3 nm. A loading rate of 37.4% for DDM drugs was obtained and in vitro release rate was calculated to be 95.4% after 80 h. On this basis,the effects of composite nanoparticles on the proliferation of porcine reproductive and respiratory syndrome virus (PRRSV) were evaluated. The results showed that when the mass concentration of bovine serum albumin-loaded DDM was 12 μg/mL,the survival rate of the MARC-145 cells was more than 90%,and the PRRSV virus proliferation was inhibited,indicating better antiviral effect than that of DDM.

Abstract:In order to understand the infection status and main epidemic subgroups of avian leukosis virus (ALV) in indigenous chicken of Hubei province,7 477 samples were collected from three local core breeds groups:the Macheng green-shell layer chicken,the Jianghan chicken and the Jingyang chicken groups,followed by the detection of the egg white p27 antigen,isolation and identification of ALV from roosters,and sequence analysis of the gp85 gene. The results showed that the positive rate of p27 antigen in the three breed groups were 1.32%,6.54% and 2.82%,respectively,and the isolation rates of ALV from roosters were 6.11%,30.14% and 8.64%,respectively,indicating that the ALV infection rate in chickens in Hubei province was relatively serious. The 15 ALV isolates can be divided into two subsets using PCR. Genetic evolution analysis of the gp85 gene showed that the J subgroup (ALV-J) and K subgroup (ALV-K) were prevalent in the three indigenous chicken breed groups,and co-infection of ALV-J and ALV-K was also found in all the three groups. The results indicated that the ALV infection in indigenous chickens in Hubei province was complicated.

Abstract:The volatile compounds of silver carp meat and yeast β-glucan were detected by HS-SPME-GC-MS and electronic nose,and the effect of yeast β-glucan on the volatile compounds of silver carp meat was investigated. The results showed that the electronic nose could distinguish different samples through the response value. A total of 28 volatile substances were identified by HS-SPME-GC-MS in silver carp meat and the volatile components were mainly aldehydes and alcohols. There were 41 volatile substances detected from the yeast β-glucan and volatile components were mostly aldehydes. In the silver carp meat added yeast β-glucan,33 volatile substances were identified. The volatile compounds contributing to the fishy off-flavor,such as hexanal,octanal,nonanal,decanal and 1-octen-3-ol,were reduced to varying degrees in this study.

Abstract:In order to analyze the effect of different amino acid residues on the thermal stability of natural collagen. The heterotrimer abc,which better mimics the low-imino content of natural collagen,was used as the research host. Different mutant collagen sequences were designed,propensities of different amino acids were considered as their thermal stability measured with circular dichroism. At the same time,the frequency of amino acids in natural collagen sequence was calculated. Based on the propensities,local stability of type Ⅰ collagen was predicted computationally. The results show that Ala,Leu and Glu at X-position and Gln,Thr,Ala and Arg at Y-position have both high propensities and high frequently occurring frequencies. The predicted local stability suggested that type Ⅰ collagen may be divided into two types of regions. One type is high-stability regions for folding of the secondary structure and the other type is low-stability ones,which may play an important role in dynamics of biological processes. The study shows that amino acids with high thermal stability and high frequency play a key role in the stability of natural collagen.

Abstract:在不破坏青砖茶样品的前提下，将近红外光谱技术与标准变量变换、一阶导数、二阶导数光谱等预处理方法和遗传算法相结合，剔除部分噪声信息和精准筛选最佳光谱信息数据点后，应用偏最小二乘法建立青砖茶茶汤品质预测模型。筛选的最佳光谱预处理方法为：标准变量变换+二阶导数，遗传算法筛选得到28个最佳建模光谱数据点；最佳偏最小二乘法模型对验证集样品的预测均方根误差为0.372 6，预测集决定系数为0.975 2；对未知茶汤品质的预测均方根误差为0.392 7，预测集决定系数0.970 2。结果表明，在青砖茶茶汤品质得分（73~93分）范围内，应用近红外光谱技术结合遗传算法和偏最小二乘法实现了对青砖茶茶汤品质的快速、准确评价。

Abstract:The absorption band of water (1 334-1 539 nm) at different temperatures of Staphylococcus aureus suspension was detected and characterized to investigate the effects of changes in the temperature of samples and bacterial concentration on the molecular structure of water and to clarify the mechanism of detecting bacterial concentration. Different spectral pretreatment methods were compared to obtain an optimal one. Multi-level component analysis (MSCA) was used to establish a first-level model (quantitative spectra-temperature relationship,QSTR) and a second-level model (quantitative spectra-concentration relationship,QSCR) for the suspension of Staphylococcus aureus. The results showed that Savitzky-Golay convolution smoothing and continuous wavelet transform was the best pretreatment method. The QSTR can accurately characterize the temperature of samples,and its corrected correlation coefficient (RC) and corrected root mean square error (RMSEC) are 0.997 and 0.37℃,respectively. The wavelengths that contribute the most to temperature correspond to the water solvation shell,OH-(H2O)1,4 and superoxide,O2-(H2O)4,free water and free OH- (S0) or trapped water and water molecules with 1 hydrogen bond (S1). RP and RMSEP in the prediction set for the Staphylococcus aureus were 0.997 and 0.37℃. The QSCR can characterize the concentration of bacterial suspension with RC of 0.887 and RMSEC of 0.891 log CFU/mL for calibration. The wavelengths that contribute the most to the concentration of bacteria correspond to V3,H2O asymmetric stretching vibration,water molecules with 1,3 and 4 hydrogen bonds (S1,S3 and S4). For the prediction of Staphylococcus aureus samples based on the secondary level model,RP of 0.869 and RMSEP of 0.858 log CFU/mL were obtained. The models built in this study have good detection accuracy and adaptability,indicating that the structural characteristics of water play an important role in detecting the temperature and bacterial concentration of bacterial suspensions.

Abstract:A rice-wheat universal pneumatic roller precision seed metering device was designed for the rice-wheat rotation area in the middle and lower reaches of the Yangtze River.The roller adopted the split-section structure,which can be disassembled and assembled from the radial direction,simplifying the disassembly and assembly process,and reducing the impact on the sealing room. Huanghuazhan rice and Zhengmai 9023 were used to conduct a single factor test to investigate the effects of socket type,rotational speed of drum,vacuum degree and height of seed in hopper on the seeding performance of the metering device evaluated by indexes including qualified rate,miss-seeding rate and reseeding rate. The working parameters was optimized and validated by orthogonal experiment. The results showed that the cone socket was suitable for rice and the ellipse socket was suitable for wheat. The effect of the height of seed in hopper on the performance was slight,while the rotational speed of the drum and the vacuum degree significantly affected the performance. The optimal working parameter combination of rice obtained from the analysis was drum speed 17 r/min,suction negative pressure 4.6 kPa,and seed layer height 40 mm; The optimal working parameter combination of wheat was drum speed 21 r/min,seed suction negative pressure 4.2 kPa,and seed layer height 40 mm. Under this parameter combination,the qualified rate of seeding and miss-seeding rate of rice were 86.81% and 4.61%,respectively; and that of wheat were 81.84% and 7.83 %,respectively. It is consistent with the optimized prediction results,and each index meets the basic requirements for seeding.

Abstract:Due to the long seed protection board structure,there are some machine empty travels in the early stage of seeding when 2BZXJ metering device series insert seed in the process of soybean plot breeding. In addition,the direction of seed discharge is the same as the advance direction of the seeder,the drop point displacement of seeds on the ground is large,and the qualified rate of plant spacing is low. Regarding the problems above,a special seed metering device for improved breeding is designed,which removes the seed protection plate,adds seed cleaning knife and seed metering groove to solve the problems of seed storage,seed mixing and empty travel of machine and tools. The ideal mathematical model of seed placement is established. The optimal location of seed placement is determined by combining with the actual structure of seed plate to solve the problems of large rolling spring displacement and low qualified rate of plant spacing. The discrete element simulation software EDEM was used to simulate and compare the draw motion at different stages of the seed metering process. The results showed that the improved breeder seeder planted earlier. The average displacement of the seeds dropped to 46% of the original average displacement,with the mean square error of displacement reduced to 1.95 mm. The average displacement fluctuation was smaller,with more stable plant spacing. Results of field comparison test showed that there are no residual seeds in the improved seeding tray,and the seeding belt was advanced. When the operating speed of the seeding machine is 0.7 m/s,the speed of the seeding device is 24 r/min,and the seed distance is 7 cm. The overall increase of the grain distance qualified index was 6.8 percentage point.The replay index and the missed broadcast index decreased by 3.4 percentage point and 3.41 percentage point. The test results verify the correctness of the simulation results. It will provide a reference for designing and studying the improved seed metering device.

Abstract:The steering wheel of a grain combine harvester was used to establish the geometric model of the steering wheel based on Pro/E software. The modal of the steering wheel combination model were analyzed by using finite element analysis software (ANSYS). The results showed that the first natural frequency of the model was 44.005 Hz,close to the range of human hand sensitive vibration frequency from 37.5 Hz to 65.0 Hz,and affected the health of operators. In order to adjust the natural frequencies of the assembly model to avoid the sensitive frequencies of human hands,the structure of the assembly was optimized by increasing the diameter of steering column and transmission shaft on the basis of replacing the material of steering wheel frame with 45 steel. After optimization,the first natural frequency of the combined body model is increased from 44.005 Hz to 67.31 Hz,avoiding the hand-sensitive vibration frequency and engine excitation frequency. The model optimized can avoid the resonance phenomenon and improve the operational comfort of operators.