Abstract In the near and future climate change scenarios, agricultural meteorological disasters, such as drought, cold damage and high temperature, will occur frequently, which will seriously affect agricultural production yield. Oligosaccharides can improve crop stress resistance and protect crop growth. Alginate oligosaccharides (AOS) were prepared by enzymatic degradation of alginate extracted from brown algae. In order to study the growth promotion behavior of Alginate oligosaccharide on wheat (Triticum aestivum L.), 25 mg/L, 50 mg/L, 100mg/L aqueous solution of AOS were applied through foliar spraying at the greening stage, jointing stage and booting stage of wheat. The effects of different treatments on wheat yield and yield components were studied in Yongshou county dry farming experiment station of northwest A&F University located in the Weibei Arid Plateau of Shaanxi province. Foliar application of alginate oligosaccharides had a significant effect on the yield of tested three varieties. The effect of leaf spraying of alginate oligosaccharides on the yield of dryland wheat was greatly related to the spraying period, alginate oligosaccharide concentration and variety. The yield of wheat was significantly increased when wheat was treated with 25 mg/L and 50 mg/L, and the yield increase range was 3.21-17.51% on CH1and TM6 variety, but the yield of ZM 175 was not significantly affected．The yield of wheat was reduced when wheat was treated with 100 mg/L. Spraying 25 mg/L and 50 mg/L alginate oligosaccharide at the greening stage, jointing stage and heading stage of wheat increased the number of grains per spike and the 1000-grain weight of wheat. The spike number, the number of grains per spike and the 1000-grain weight of wheat were the main factors that formed wheat yield. Alginate oligosaccharides increased the levels of these three factors, thus increasing wheat yield.

为了促进农药的降解,减少农作物中的农药残留量,本研究归纳了农药降解的方法,主要包括光解、化学降解和生物降解,分析了各种农药降解方法的优点和缺点,总结了外源物质(农药安全剂、油菜素内酯、褪黑素)促进农作物体内农药降解的途径及机理.指出了寡糖降低作物中农药残留的作用以及可能的机理,提出了关于促进农作物体内农药降解研究方面存在的一些问题以及建议.期望对降低农作物中农药残留有积极作用,对农业具有指导作用.

Fucoidan oligosaccharides possesses diverse physicochemical and biological activities. Specific glycoside hydrolases are valuable tools for degrading polysaccharides to produce oligosaccharides. In this study, BcFucA, a novel fucosidase belonging to GH95 family from Bacillus cereus 2-8, was cloned into pET21a vector, expressed in E. coli BL21 (DE3) and characterized. The protein consists of 1136 amino acid residues encoded by 3411 bases and has a molecular weight of 125.35 kDa. The optimal temperature and pH of this enzyme are 50 degrees C and pH 4.0. In addition, this study showed that the unknown function domain (encoding Lys261-Thr681) defined as a linker is quite important for its activity. The obtained novel enzyme BcFucA will contribute to the effective degradation of fucoidan and future industrial applications.

O-岩藻糖基转移酶(protein O-fucosyltransferase,POFUT)是催化蛋白质O-岩藻糖基化的关键酶,被证实与动物的生理病理过程密切相关.但在植物中,POFUT的鉴定和功能研究尚处于起步阶段.首先通过同源序列的BLAST和生物信息学分析,推测在拟南芥基因组中AT3G05320编码的蛋白具有潜在的PO-FUT活性,并将其命名为AtPOFUT1.利用毕赤酵母真核表达体系实现AtPOFUT1蛋白的异源表达,初步检测明确该重组蛋白具有POFUT活性.进一步利用公共基因芯片数据对AtPOFUT1表达模式进行分析,发现AtPOFUT1在植物的生长发育和抗病抗逆等过程发挥重要作用.对AtPOFUT1缺失突变体的表型统计分析,发现突变体表现出种子数量减少且发育不良等性状,明确AtPOFUT1在拟南芥生长发育中的重要功能.上述研究初步揭示AtPOFUT1的催化活性及部分生理功能,可为植物中POFUT的鉴定及生物学功能研究工作提供一定参考.

魔芋产业发展迅速,已成为中国西部经济发展中最具成长潜力与竞争优势的地方特色资源产业.在魔芋种植过程中,软腐病发生严重,已成为限制魔芋产业发展的主要因素.传统的化学农药防治效果不理想,急需寻找新的防治途径.为研究出有效的防治魔芋软腐病新技术,应用壳寡糖、海藻酸寡糖植物免疫诱导剂,结合使用噻霉酮制剂,在陕西安康针对魔芋软腐病防治技术进行初步研究.结果 表明:药剂拌种处理效果好于浸种处理效果,浸种处理只有噻霉酮对魔芋软腐病有一定的防治效果,防效为51.17％.噻霉酮、壳寡糖及农用链霉素单一药剂对种芋拌种处理,对魔芋软腐病防效分别为68.92％、55.36％和56.49％,噻霉酮及壳寡糖拌种处理对出苗有明显的促进作用.拌种处理结合在成株期喷施壳寡糖、海藻酸寡糖和噻霉酮,对魔芋软腐病有较好的防治效果,防治效果50％～70％,延迟魔芋魔芋软腐病的爆发高峰期约一周,提高产量效果明显.用噻霉酮杀菌剂拌种处理种芋,在发病初期再用壳寡糖或海藻酸寡糖植物免疫诱导剂结合噻霉酮喷施植株,对魔芋软腐病有较好的防治效果.

为了探讨拟南芥O-岩藻糖基转移酶(SPINDLY)在病原体相关分子模式诱导抗性中的作用,该研究以SPINDLY缺失拟南芥突变体spy-3为实验材料,从叶片表型、病情指数、病菌定殖量以及丁香假单胞菌(PstDC3000)关键基因的表达水平等指标,系统考察了SPINDLY在壳寡糖诱导拟南芥抗Pst DC3000中的功能.结果 显示;(1)spy-3突变体比野生型更易被PstDC3000侵染.(2)与病菌侵染组相比,壳寡糖预处理明显缓解植株叶片黄化现象,显著降低PstDC3000的定殖量.(3)壳寡糖预处理的spy-3植株中水杨酸和茉莉酸途径相关基因的表达量及水杨酸和茉莉酸含量均较病菌侵染组明显升高.(4)壳寡糖在spy-3中的诱抗效果与野生型相比无明显差别.研究表明,SPINDLY在植物先天免疫过程发挥重要作用,但并不影响壳寡糖的诱导抗性.

Alginate oligosaccharide (AOS) is the degradation product of alginates extracted from brown algae. As a mul-tifunctional oligomer, it has attracted widespread attention in plant research. Different methods of preparation generate AOS possessing diverse structural properties, and result in differences in AOS activity. In this review, the methods of preparation and characterization of AOS are briefly summarized, followed by a systematic in-troduction to the activity and mechanisms of AOS in plants. AOS can act as a growth promoter at different growth stages of plants. AOS also enhances resistance to pathogens, drought, salt, heavy metals and other stressors by triggering plant immunity, exerting bioactivity just like a pathogen-associated molecular pattern. In addition, AOS can regulate ABA biosynthesis and metabolite to preserve fruit quality and enhance shelf life. This review provides a comprehensive summary of the biological activity of AOS in plants, which will support re-search and the application of AOS treatments for plants in the future.

糖基转移酶1家族,也称尿苷二磷酸糖基转移酶(Uridine diphosphate glycosyltransferase,UGT),是植物解毒系统中最重要的多基因家族之一.该研究基于公共基因芯片数据对拟南芥(Arabidopsis thaliana)的106个UGT基因进行生物信息学分析,期望找到参与广谱农药代谢的UGT靶标.从NCBI数据库收集并重注释关于农药和除草剂安全剂处理的基因芯片数据,差异表达分析和聚类分析表明8个UGT在绝大部分农药处理中均显著转录上调,是重要候选基因.基因本体论(Gene ontology,GO)富集分析表明,候选UGT的共表达基因富集于植物4相代谢解毒过程,暗示这些UGT基因的广谱解毒能力.最后以候选UGT基因及其共表达基因构建共表达网络,发现网络中的桥接节点也参与了植物解毒过程,表明UGT76B4和UGT76B5是最关键的参与多种农药代谢的UGT基因.

Chito/chitin oligosaccharides has positive effects on triggering the resistance mechanism of plants. In 1980, it was first reported that chito/chitin oligosaccharide could induce plant immunity. Since then, chito/chitin oligosaccharide has been considered as a potent elicitor of plant immunity that is used in many crops, such as rice, wheat, cucumber, pepper, oilseed rape, tomato, bean, tobacco, flower crops, fruit crops and so on. This part summarized the study about the effect of the chito/chitin oligosaccharide application in lab/field experiments, In the studies, researchers found that chito/chitin oligosaccharide stimulates a variety of plant responses, which are mainly about the effects of chito/chitin oligosaccharide on inducing plant disease resistance, promoting plant growth and preventing plant from abiotic stress, such as cold stress. These effects demonstrate the ability of chito/chitin oligosaccharide to control plant fungi and virus diseases, enhance plant growth and yield, as well as prolong the shelf life of flowers and fruits. Meanwhile, the applications of chito/chitin oligosaccharide derivatives chemical constitution and the effect of used as plant disease vaccine are also reviewed, and the complexity mechanism of chito/chitin oligosaccharide activated plant immunity is discussed. Plant induced disease resistance and the mechanism has been studied for a long time, but its application in agricultural production has not fully developed. Considering the excellent physical properties - high solubility, nontoxicity, bio-compatibility and the cost advantage - rich in production, low cost, the excellent effects on plants, chito/chitin oligosaccharide showed huge economic benefits and will have a good application prospect.

Alginate Oligosaccharide (AOS) is a natural biological carbohydrate extracted from seaweed. In our study, Arabidopsis thaliana was used to evaluate the AOS-induced resistance to Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Resistance was vitally enhanced at 25 mg/L in wild type (WT), showing the decreased disease index and bacteria colonies, burst of ROS and NO, high transcription expression of resistance genes PR1 and increased content of salicylic acid (SA). In SA deficient mutant (sid2), AOS-induced disease resistance dropped obviously compared to WT. The disease index was significantly higher than WT and the expression of recA and avrPtoB are two and four times lower than WT, implying that AOS induces disease resistance injecting Pst DC3000 after three days treatment by arousing the SA pathway. Our results provide a reference for the profound research and application of AOS in agriculture.

Enzymatic digestion of sodium alginate to produce specific oligosaccharides has attracted great attention. However, commercial enzymes that efficiently produce specific oligosaccharides are still unavailable. In the present study, a novel gene encoding an alginate lyase (designated alg7A) was cloned from the marine bacterium Vibrio sp. W13 and expressed in E. coli. The recombinant Alg7A shows high activities toward alginate, poly-α-l-guluronate (polyG), poly-β-d-mannuronate (polyM) and polyMG, and more preferred to polyMG. Moreover, the enzyme contains a highly conserved domain of the Polysaccharide Lyase (PL) 7 family (R*E*R, Q*H and Y*KAG*Y*Q), which indicates that it belongs to PL7. Furthermore, the thin layer chromatography and ESI-MS analysis showed that Alg7A mainly releases trisaccharides from alginate. These results demonstrated that Alg7A has a great potential to be used to produce oligosaccharides from alginate.

Antrodia cinnamomea (AC), an edible fungus growing in Taiwan, has various health benefits. This study was designed to examine the potential inhibitory effects of AC oligosaccharides on lipopolysaccharide (LPS)-induced inflammatory responses in vitro and in vivo. By trifluoroacetic acid degradation, two oligosaccharide products were prepared from AC polysaccharides at 90 °C (ACHO) or 25 °C (ACCO), which showed different oligosaccharide identities. Compared to ACCO, ACHO displayed better inhibitory effects on LPS-induced mRNA expression of pro-inflammatory cytokines including IL-6, IL-8, IL-1β, TNF-α and MCP-1 in macrophage cells. Further, ACHO significantly suppressed the inflammation in lung tissues of LPS-injected C57BL/6 mice. The potential anti-inflammatory molecular mechanism may be associated with the promotion of protein O-GlcNAcylation, which further skewed toward the marked suppression of p38 and Akt phosphorylation. Our results suggest that the suppressive effect of AC oligosaccharides on inflammation may be an effective approach for the prevention of inflammation-related diseases.

Gut microbiota has been proved to be an indispensable link between nutrient excess and metabolic syndrome, and chitin oligosaccharide (NACOS) has displayed therapeutic effects on multiple diseases such as cancer and gastritis. In this study, we aim to confirm whether NACOS can ameliorate high-fat diet (HFD)-induced metabolic syndrome by rebuilding the structure of the gut microbiota community. Male C57BL/6J mice fed with HFD were treated with NACOS (1 mg/mL) in drinking water for five months. The results indicate that NACOS improved glucose metabolic disorder in HFD-fed mice and suppressed mRNA expression of the protein regulators related to lipogenesis, gluconeogenesis, adipocyte differentiation, and inflammation in adipose tissues. Additionally, NACOS inhibited the destruction of the gut barrier in HFD-treated mice. Furthermore, 16S ribosome RNA sequencing of fecal samples demonstrates that NACOS promoted the growth of beneficial intestinal bacteria remarkably and decreased the abundance of inflammogenic taxa. In summary, NACOS partly rebuilt the microbial community and improved the metabolic syndrome of HFD-fed mice. These data confirm the preventive effects of NACOS on nutrient excess-related metabolic diseases.

The aim of this study is to investigate the effect of chitosan oligosaccharides (COS) on type 2 diabetes mellitus. Wild type C57BL/6J mice or diabetic db/db mice were treated with vehicle or COS for three months. COS treatment significantly decreased the blood glucose (P < 0.01) and reversed the insulin resistance (P < 0.05) in db/db mice, which was accompanied by suppressing the inflammation mediators (P < 0.05), down-regulating the lipogenesis (P < 0.01) and inhibiting the adipocyte differentiation (P < 0.05) in white adipose tissue. Additionally, COS treatment inhibited the reduction of occludin (P < 0.01) and relieved the gut dysbiosis in diabetic mice by promoting Akkermansia (P < 0.01) and suppressing Helicobacter (P < 0.05). Spearman's correlation analysis indicates that the COS-modulated bacteria are positively correlated with inflammation, hyperglycemia and dyslipidemia. The functional profiling based on the microbiota composition implicated that COS treatment may regulate the metabolic pathways of gut microbiota. In summary, COS treatment remarkably improved the glucose metabolism and reshaped the unbalanced gut microbiota of diabetic mice. Our study provided the evidence for application of COS to the treatment of diabetes mellitus.

BACKGROUND:N-Acetylcysteine (NAC), an antioxidative reagent for clinical diseases, shows potential in the treatment of diabetes and other metabolic diseases. However, it is unknown how NAC modulates the gut microbiota of mice with metabolic syndrome. The aim of the present study was to demonstrate the preventive effect of NAC on intestinal dysbiosis and glucose metabolic disorder. METHODS:Mice (C57BL/6J strain) were fed either a normal chow diet (NCD), NCD plus NAC, a high-fat diet (HFD), or HFD plus NAC for 5 months, after which glucose levels, circulating endotoxins and key metabolism-related proteins were determined. Fecal samples were analyzed by 16S rRNA sequencing. A novel analysis was performed to predict functional changes in gut microbiota. In addition, Spearman's correlation analysis was performed between metabolic biomarkers and bacterial abundance. RESULTS:Treatment with NAC significantly reversed the glucose intolerance, fasting glucose concentrations, and gains in body weight and plasma endotoxin in HFD-fed mice. Further, NAC upregulated occludin and mucin glycoprotein levels in the proximal colon of HFD-treated mice. Noticeably, NAC promoted the growth of beneficial bacteria (i.e. Akkermansia, Bifidobacterium, Lactobacillus and Allobaculum) and decreased populations of diabetes-related genera, including Desulfovibrio and Blautia. In addition, NAC may affect the metabolic pathways of intestinal bacteria, including lipopolysaccharide biosynthesis, oxidative stress, and bacterial motility. Finally, the modified gut microbiota was closely associated with the metabolic changes in NAC-treated HFD-fed mice. CONCLUSIONS:N-Acetylcysteine may be a potential drug to prevent glucose metabolic disturbances by reshaping the structure of the gut microbiota.

The plant immune elicitors can induce a line of defense responses in plants and are identifed as new type of biological pesticides. At present stage, new plant immune elicitor is screening with potted plants or field experiments, which is time-consuming and high-cost. The droplet microfluidic technology, which is originated from analytical chemistry and owns micro-channel network structure, has properties of high throughput, high sensitivity, low consumption of reagent, no cross contamination and rapid reaction. These advantages provide a novel platform for screening plant immune elicitors. Chitosan oligosaccharides (COS) are obtained by degradation of chitosan. It was reported that COS could activate plant innate immunity, such as: stimulate H2O2 (hydrogen peroxide)production, induce defense response by NO (nitric oxide) pathway, make a synthesis of phytoalexin, impact the jasmonic acid / ethylene (JA/ET) signaling marker, trigger defense-related gene expression, cause changes in protein phosphorylation, activate mitogen-activated protein kinases (MAPKs), and possess antimicrobial activity against bacteria and fungi in plant. Because of the advantages and the high solubility, nontoxicity, and biocompatibility, COS are considered as an effective plant immune elicitor by researchers. To preliminarily applying droplet microfluidic technology in plant immune elicitor screening, integrated microfluidic chip with droplets formation structure was designed and fabricated. COS were chosen as positive reagent, and BY-2 tobacco cells played as model plant cell. The flow rate of mobile phase was measured and established for BY-2 tobacco cells droplets formation, and the single cell encapsulating efficiency was calculated. Then COS and NO probe were dumped into the droplets with BY-2 tobacco cells, and the fluorescence intensity of NO probe from droplets was detected to evaluate the feasibility of screening the plant immune elicitor COS. To make the comparative analysis, the fluorescence intensity was compared with the same reaction system in 96-well plate. The results showed that at the flow rates of 100μL/h in cell suspension and 300μL/h in oil, the sizes of generated droplets were suitable to encapsulate the cells. The BY-2 cell clusters could be dispersed in isotonic solution, and every droplet encapsulated single cell. The ratio of droplets encapsulating single cell was about 22.9%. The ratio conformed to Poisson distribution. The fluorescence intensity of droplets incubated with COS was detected by fluorescence microscope. The fluorescence intensity from the COS/NO probe/BY-2 cell group was significantly higher than the control groups. In the comparative analysis experiments, the fluorescence intensity of droplets showed similar trend compared with the same reaction system in 96-well plate. This result implied that the cell treated with COS in droplets showed similar trend in defense responses compared to traditional screening method with 96-well plate. Thus, the droplets with COS / NO probe / BY-2 cell show high fluorescence intensity that can be detected by fluorescence microscope, which implies that integrated with fluorescence detecting technique, droplets microfluidics and fluorescence probe can be a novel platform for screening plant immune elicitors.

Based on droplet microfluidics technology,we detected immunological stress singling mole cules (H2O2 and Ca2+) secreted by BY-2 cells under simulation of chitosan oligosaccharide (COS) in the paper.BY-2 cells labeled with H2DCF-DA and Fluo-3AM were stimulated by 50 μg/mL COS solution,and fluorescence was detected.We optimized our parameters for this droplet microfluidics platform and could achieve ideal encapsulation of BY-2 cells at an aqueous phase flow rate of 100 μL/h,an oil phase flow rate of 300 μL/h,and a droplet diameter of 300 μm.Under the optimized conditions,COS and fluorescence-labeled BY-2 cells encapsulated in droplets and fluorescence was observed.Then the fluorescence intensity of droplet-encapsulated BY-2 cells were measured by microplate reader and the unencapsulated cells in 96-well plate were taken as the control group.The results indicated that within 1 h,the trend of the intensity changed similarly,and this could provide the guidance for microfluidics-based research in plant immune inducer and biopesticides.

为了解壳寡糖对低温胁迫下小麦的保护作用,对两个小麦品种(小偃22和西农9871)幼苗喷施100 mg·L-1壳寡糖和0℃低温胁迫96 h,检测叶片的损伤面积及丙二醛、脯氨酸、可溶性糖、还原糖含量,并调查复温后返青率.结果表明,与常温对照组相比,低温胁迫48 h后壳寡糖处理的小麦叶片损伤面积和丙二醛含量增幅较低,其中小偃22和西农9871的损伤面积相对于低温对照分别减少了25.3％和28.8％,丙二醛含量分别降低了16.9％和33.7％;同时,两个品种叶片脯氨酸含量分别提高了15.8％和26.7％,还原糖含量分别提高了25.6和14.3％,可溶性糖含量也表现出增高的趋势.经过复温培养,壳寡糖处理下小偃22和西农9871的返青率分别提高了4.6％和5.9％.说明壳寡糖可通过促进小麦苗脯氨酸、还原糖等低温抗性相关次生代谢物的表达,提高其对低温寒害的抵抗能力.

分别以不同浓度(25ppm、50ppm、100ppm、200ppm)的氨基寡糖素对番茄种子进行浸种处理,各处理均可提高番茄苗的抗寒性,其中100ppm的处理效果最好,番茄株高、根系长度、干重分别比对照组增加13.3、27.2、19.5％,叶绿素含量、根系活力、可溶性总糖分别比对照组高23.2、38.3、19.5％.

In order to evaluate the effects of Qishanbao on the growth promotion, yield increase and disease prevention of sunflower, a field experiment was carried out in Jingbian county of Shan'xi Province through seed dressing and seedling spraying with Qishanbao in 2011 and 2012. The result showed that Qishanbao could promote crop rooting, make leaf thick and dark green, increase plant height, while the yield of the sunflower increased someway. At the same time, it could also improve the sunflower's resistance to sunflower sclerotinia stalk/head rot, sunflower verticillium wilt and sunflower leaf spot. The good growth promotion and disease control effects of Qishanbao showed its good application value in the sunflower pro-duction.