Effect of plant extracts on activity of some defense enzymes of apple fruit in interaction with Botrytis cinerea

The efficacy of seven plant extracts(neem,fennel,lavender,thyme,pennyroyal,salvia and asafetida) in controlling postharvest of apple(caused by Botrytis cinerea) was evaluated in vitro and in vivo.In vitro,all plant extracts treatments inhibited spore germination.Inhibitory rates of pore germination was 17.41 and 20.83% for neem extract treatment(methanolic and aqueous extracts,respectively) with significant difference compared to control(73.6 and 85.33%) for aqueous and methanol extracts.In the storage conditions,the application of aqueous extract of neem(at concentration of 25%) resulted in 89.11% reduction of disease severity compared with the untreated control.Results of enzymes activity showed the plant extracts can increase the activity of peroxidase,phenylalanine ammonia-lyase,β-1,3-glucanase and polyphenol oxidase in the presence of pathogens,in apple fruits.However,the results of this research revealed that application of neem extracts was more effective than the application of other plant extracts.According to this study,it could be concluded that plant extracts may be useful to control postharvest disease as a safe alternative option to chemical fungicides.

Novel 18β-glycyrrhetinic acid amide derivatives show dual-acting capabilities for controlling plant bacterial diseases through ROS-mediated antibacterial efficiency and activating plant defense responses

Natural products have long been a crucial source of,or provided inspiration for new agrochemical discovery.Naturally occurring 18β-glycyrrhetinic acid shows broad-spectrum bioactivities and is a potential skeleton for novel drug discovery.To extend the utility of 18β-glycyrrhetinic acid for agricultural uses,a series of novel 18β-glycyrrhetinic acid amide derivatives were prepared and evaluated for their antibacterial potency.Notably,compound 5k showed good antibacterial activity in vitro against Xanthomonas oryzae pv.oryzae(Xoo,EC50=3.64 mg L–1),and excellent protective activity(54.68%)against Xoo in vivo.Compound 5k induced excessive production and accumulation of reactive oxygen species in the tested pathogens,resulting in damaging the bacterial cell envelope.More interestingly,compound 5k could increase the activities of plant defense enzymes including catalase,superoxide dismutase,peroxidase,and phenylalanine ammonia lyase.Taken together,these enjoyable results suggested that designed compounds derived from 18β-glycyrrhetinic acid showed potential for controlling intractable plant bacterial diseases by disturbing the balance of the phytopathogen’s redox system and activating the plant defense system.

Breeding of Brassica napus Cultivar Zhongshuang9 with High-Resistance to Sclerotinia sclerotiorum and Dynamics of Its Important Defense Enzyme Activity

Zhongshuang9, a new semi-winter Brassica napus variety with high resistance to Sclerotinia sclerotiorum and lodging, high-yield, double-low quality and extensive adaptability, was bred by multiple crossing and microspore culture technique. It was registered and released in China in 2002. In regional trial of Hubei Province in China, Zhongshuang9 yielded 2 482. 2 kg ha-1 averagely in 2000 - 2002, 15. 33% higher than the control variety Zhongyou821. Erucic acid, glucosinolates and oil contents of Zhongshuang9 were 0.23%, 22.69 μmol g-1(in meal)and 42%, respectively. In field assessment of resistance to S. Sclerotiorum , the disease incidence and disease index of Zhongshuang9 averaged 13.31 % and 6.47, respectively, which were lower than those of Zhongyou821 by 28% and 36%, respectively. After inoculation of detached leaves with mycelia, the lesion size of Zhongshuang9 was 4. 709 cm2, which was significantly smaller than that of the mid-resistant variety Zhongyou821(5. 933 cm2). The stem lesion length of Zhongshuang9 after match-stick inoculation was 1.275 cm, which was significantly lower than that of Zhongyou821(1.943 cm). The possible mechanism of resistance to S. sclerotiorum was studied through comparing the activities of phenylalanine ammonia lyase(PAL), exo-chitinase, β-1, 3-glucanase, peroxidase(POD)and polyphenoloxidase(PPO)in Zhongshuang9 with those in other resistant, mid-resistant and susceptible cultivars.

Systemic Activation of Defensive Enzymes and Protection in Tobacco Plantlets against <i>Phytophthora nicotianae</i>Induced by Oligosaccharins

Oligosaccharins are potent biomolecules which activate defense responses and resistance in tobacco plants. However, it is not known the systemic behavior of defensive enzymes activated by these elicitors. In this work, the dynamic behavior of key defensive enzymes was evaluated in tobacco plant leaves previously treated through the roots with chitosan polymer (CH), chitosan (COS) and pectic (OGAS) oligosaccharides and Spermine (Sp). All macromolecules tested activated protein levels and defense enzymatic activity in tobacco leaves but with different response dynamics among them and depending on the biochemical variable evaluated. Defense response above control levels were detected since 12 hours after treatments and it consisted in a biphasic behavior with two peaks for PAL (EC 4.3.1.5) and β 1 - 3 glucanase (EC 3.2.1.6) enzymatic activities. The highest enzymatic levels for these enzymes were achieved at 48 hours in plantlets elicited with COS and at 72 hours for those plants treated with chitosan polymer, while the highest POD (EC 1.11.1.6) activity was detected with CH between 48 and 72 hours. These results demonstrated systemic defense activation by oligosaccharins in tobacco whose dynamic of defense response is affected by the kind of oligosaccharins tested. When applying OGAS by foliar spray on tobacco, systemic resistance against Phytoththora nicotianae was induced and plantlets were protected with the low concentration tested by 46% under the bioassays conditions performed. Moreover, enzymatic determinations on roots and leaves previous to plant-pathogen interaction showed increments above 30% of control levels for PAL and POD activities. It means that oligosaccharins activate local and systemic defense responses in plants in the absent of pathogen infection.

Induced defense responses in rice plants against small brown planthopper infestation

The small brown planthopper(SBPH), Laodelphax striatellus Fallén(Homoptera: Delphacidae), is a serious pest of rice(Oryza sativa L.) in China. To understand the mechanisms of rice resistance to SBPH, defense response genes and related defense enzymes were examined in resistant and susceptible rice varieties in response to SBPH infestation. The salicylic acid(SA) synthesis-related genes phenylalanine ammonia-lyase(PAL), NPR1, EDS1 and PAD4 were induced rapidly and to a much higher level in the resistant variety Kasalath than in the susceptible cultivar Wuyujing 3 in response to SBPH infestation. The expression level of PAL in the Kasalath rice at 12 h post-infestation(hpi) increased 7.52-fold compared with the un-infested control, and the expression level in Kasalath was 49.63, 87.18, 57.36 and 75.06 times greater than that in Wuyujing 3 at 24, 36, 48 and 72 hpi, respectively. However, the transcriptional levels of the jasmonic acid(JA) synthesis-related genes LOX and AOS2 in resistant Kasalath were significantly lower than in susceptible Wuyujing 3 at 24, 36, 48 and 72 hpi. The activities of the defense enzymes PAL, peroxidase(POD), and polyphenol oxidase(PPO) increased remarkably in Kasalath in response to SBPH infestation, and were closely correlated with the PAL gene transcript level. Our results indicated that the SA signaling pathway was activated in the resistant Kasalath rice variety in response to SBPH infestation and that the gene PAL played a considerable role in the resistance to SBPH.

Effect of cadmium on the defense response of Pacific oyster Crassostrea gigas to Listonella anguillarum challenge

Heavy metal pollution can affect the immune capability of organisms.We evaluated the effect of cadmium(Cd) on the defense responses of the Pacific oyster Crassostrea gigas to Listonella anguillarum challenge.The activities of several important defensive enzymes,including superoxide dismutase(SOD),glutathione peroxidase(GPx),acid phosphatase(ACP),Na+,K+-ATPase in gills and hepatopancreas,and phenoloxidase-like(POL) enzyme in hemolymph were assayed.In addition,the expression levels of several genes,including heat shock protein 90(HSP90),metallothionein(MT),and bactericidal/permeability increasing(BPI) protein were quantified by fluorescent quantitative PCR.The enzyme activities of SOD,ACP,POL,and GPx in hepatopancreas,and the expression of HSP90 were down-regulated,whereas GPx activity in the gill,Na+,K+-ATPase activities in both tissues,and MT expression was increased in Cdexposed oysters post L.anguillarum challenge.However,BPI expression was not significantly altered by co-stress of L.anguillarum infection and cadmium exposure.Our results suggest that cadmium exposure alters the oysters' immune responses and energy metabolism following vibrio infection.

Photosynthetic traits and antioxidative defense responses of Pinus yunnanensis after joint attack by bark beetles Tomicus yunnanensis and T.minor

Bark beetles Tomicus yunnanensis and T.minor are two important pests of Pinus yunnanensis and can cause massive death of pine trees.In this study,we examined several traits related to photosynthesis in P.yunnanensis and their relationship with antibiotic defense responses after joint attack by the two bark beetles at the shoot and the trunk stages.When shoots were attacked by the beetles,the abundance of chlorophylls,carotenoids,and the rates of net photosynthesis(Pn)and transpiration(E)decreased in needles,while the levels of superoxide dismutase and malondialdehyde remained unchanged in both needles and phloem.The activity of peroxidases also remained unchanged in needles,but increased in phloem.The activity of catalases increased in both needles and phloem.When trunks were attacked by the bark beetles,chlorophyll abundance,Pn,E,and antioxidative enzyme activities all declined,and the declines were more pronounced than in the attacked shoots.A decrease in protein concentrations was also observed in needles and phloem from the attacked pines.Attack on shoots by the bark beetles suppressed host defense and provided a favorable environment for larval growth and development,resulting in long-term decline of pine growth potential.The results suggest that attacks on trunks by beetles caused more severe damage to host trees than attacks on shoots.

Enhancement of defense responses by <i>Clonostachys rosea</i>against Botrytis <i>cinerea</i>in tomatoes

Clonostachys rosea (C. rosea) is a biocontrol agent that is used to combat and prevent phytopathogenic fungi attacks because of its ability to involve many factors and diverse modes of action. The reactions of C. rosea on the control of gray mold disease in tomato leaves were investigated in this study. To investigate the reactions of C. rosea in inducing resistance to tomato plants, three treatments, including Botrytis cinerea treatment (treatment B), C. rosea treatment (treatment C), C. rosea and B. cinerea treatment (treatment C + B) and water (control), to be applied on tomato leaves were set up. Disease severity was subsequently evaluated and compared with the control. The treatment of tomato leaves with C. rosea (15 μg/ml) significantly reduced the disease index after inoculation and severity of gray mold caused by Botrytis cinerea. The results indicated that the C. rosea treatment stimulated the activity of the defense related enzymes: Peroxidases (POX), lipoxygenases (LOX) and glutathione S-transferases (GST), and the treatment C + B reduced the incidence and severity of the gray mold. Furthermore, C. rosea treatment increased the activity of pathogenesis related proteins PR1. Therefore, our results suggest that C. rosea could enhance the resistance of tomato plants to gray mold through the activation of defense genes and via the enhancement of defense-related enzymatic activities.

复合木霉制剂防治黄连根腐病及其机理研究

为评价复合木霉制剂对黄连根腐病的防治效果,并揭示其防病机理,为黄连根腐病专用微生物农药的研发奠定基础,本试验将深绿木霉Trichoderma atroviride、长枝木霉T.longibrachiatum、钩状木霉T.hamatum、拟康宁木霉T.koningiopsis等4种木霉配制的复合制剂和尖镰孢Fusarium oxysporum以不同的方式分别施用于黄连,统计根腐病发生情况,检测黄连根部防御酶活性,用高通量测序分析根际土壤真菌群落结构。结果表明,复合木霉制剂对尖镰孢导致的根腐病具有明显预防效果;复合木霉制剂和尖镰孢分别接种黄连可提高SOD、POD、CAT、PAL、PPO等防御性酶活性,产生诱导抗性;而它们先后接种黄连可产生强化效应,从另一个途径提高植株抗病性。复合木霉制剂和尖镰孢都会降低真菌的数量、多样性,和某些真菌的相对丰度,而复合木霉制剂的抑菌作用更强烈,尤其能明显抑制尖镰孢、Ilyonectria sp.等病原真菌的生长,且能改善土壤真菌群落结构。木霉和尖镰孢都能在土壤中较长期定殖。可见,复合木霉制剂可以预防尖镰孢导致的黄连根腐病,防病机理包括诱导黄连植株产生抗性,接种后再遭受病原菌侵染产生的强化效应,优化土壤真菌群落结构,抑制土壤中病原菌等,且有效期较长。因此复合木霉制剂具有开发为微生物农药防治黄连根腐病的潜力。

外源茉莉酸甲酯诱导大麦叶斑病抗性研究

【目的】探讨不同浓度外源茉莉酸甲酯(MeJA)诱导大麦抗叶斑病效应差异及其分子机制,为应用MeJA防治大麦叶斑病提供理论依据。【方法】以‘蒙啤麦3号’大麦品种幼苗为材料,设置不接菌(无菌水处理叶片)、接菌(无菌水处理叶片接种麦根腐平脐蠕孢菌)和接菌+MeJA(0.5,1.0,1.5,2.0,2.5mmol/LMeJA喷施叶片后接菌)3组处理,于三叶期调查叶斑病发病情况,并据此筛选最适MeJA浓度,然后测定不接菌、接菌及接菌+MeJA(最适浓度)下不同处理时间叶片的抗氧化酶、抗病相关酶活性、丙二醛含量、渗透调节物质含量以及相关基因表达水平。【结果】(1)叶面喷施外源MeJA提高了大麦对叶斑病的抗性,1.5mmol/LMeJA处理叶片的病情指数较对照显著降低19.03%,诱导抗性效果最佳;(2)与单独接菌处理相比,1.5mmol/LMeJA处理大麦叶片超氧化物歧化酶、过氧化物酶、过氧化氢酶、几丁质酶和β-1,3-葡聚糖酶活性均显著提高,而其丙二醛、脯氨酸、可溶性糖和可溶性蛋白含量显著降低,同时受MeJA调控转录因子及编码抗病相关酶的基因表达量显著上调。【结论】外源喷施1.5mmol/LMeJA通过调节抗病相关酶活性和渗透调节物质含量,以及调控抗病相关酶基因及茉莉酸信号途径关键转录因子基因表达,进而提高大麦植株的叶斑病抗性。

大气CO_(2)浓度升高和温升对水稻纹枯病侵染后的相关蛋白和防御酶的影响

纹枯病(sheath blight)作为一种土传病害,其发生和发展严重威胁到水稻(Oryza sativa L.)的生产。目前,大气CO_(2)浓度([CO_(2)])和温度升高如何影响感病植株内病程相关蛋白(pathogenesis related proteins,PR蛋白)和防御酶尚不清楚。本研究以纹枯病易感品种(Lemont)和抗性品种(YSBR1)为实验材料,利用田间开放式自由大气[CO_(2)]和温度升高(T-FACE)平台设置四个处理:对照、[CO_(2)]升高([CO_(2)]升高至590μmol·mol–1)、温升(冠层温度升高2℃)及[CO_(2)]升高和温升交互,通过人工接种Rhizoctonia.solani,探究不同抗性品种叶片和茎鞘PR蛋白与防御酶活性,以及土壤基本理化性状的响应。研究结果表明:高[CO_(2)]和温升下耕作土制成的土壤浸提液培养基中R.solani生长速率无显著差异,接种R.solani后病斑发展速率与土壤基本理化性状无关。水稻植株感病后,两个品种叶片和茎鞘中PR蛋白和相关防御酶表现出明显差异,且在高[CO_(2)]和温升条件下,该差异进一步增大。对于茎鞘中的PR蛋白和防御酶,高[CO_(2)]和温升交互处理明显增加Lemont和YSBR1茎鞘中过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)、β-1,3-葡聚糖酶(GLU)和超氧化物歧化酶(SOD)活性。对于两个水稻品种,当R.solani入侵后,在各处理下,YSBR1叶片中PR蛋白和相关防御酶以及茎鞘中SOD和CAT活性均显著高于Lemont,且YSBR1病斑发展速率显著低于Lemont。在整个发病过程中,温升处理及其与高[CO_(2)]互作处理均显著增加易感品种Lemont的病斑发展速率(增加了21%~45%),而对抗性品种YSBR1的病斑发展速率无显著影响。相关性分析结果表明,各处理下Lemont和YSBR1植株纹枯病病斑的发展速率均与其茎鞘中GLU活性存在显著正相关。因而,在R.solani侵染后,抗病品种中较高的PR蛋白和防御酶活性形成的防卫反应,能够有效减轻未来高[CO_(2)]和温升条件对纹枯病病斑发展速度的影响。研究结果对选育纹枯病抗性品种来适应未来气候变化背景下的水稻生产提供重要的借鉴意义。

海藻酸寡糖诱导黄瓜抗灰霉病效果及其机理研究

为了研究海藻酸寡糖对黄瓜灰霉病的防治效果及诱导抗病机理,以黄瓜感病品种3叶期植株为试材,通过盆栽试验、酶活测定法和实时荧光定量,测定接菌后0~48 h内,黄瓜叶片的防御相关酶活性[超氧化物歧化酶(SOD)活性、氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)活性、氧化物酶(POD)活性]和信号转导途径关键基因表达量(茉莉酸途径关键基因JAR1和EIN2;水杨酸途径关键基因NPR1和PR1)。结果表明:(1)海藻酸寡糖的最佳诱导浓度为50 mg/L,诱导时间为3 d,防效可达66.75%;(2)防御相关酶的活性均显著提高;(3)水杨酸途径关键基因NPR1和PR1相对表达量均上调。可见海藻酸寡糖通过激发水杨酸信号转导,提高植株体内防御相关酶活,增加植株抗病性。

棘孢木霉PT-29与枯草芽孢杆菌S-16共培养对马铃薯枯萎病的防控作用

马铃薯枯萎病是一种土传真菌病害,可对马铃薯整个生育期造成严重危害,在全国主要马铃薯产区都有不同程度的发生。为减少化学药剂防治马铃薯枯萎病带来的弊端,提高生防菌剂效果,研究了棘孢木霉(Trichoderma asperellum)PT-29与枯草芽孢杆菌(Bacillus subtilis)S-16对马铃薯枯萎病主要致病菌尖孢镰刀菌(Fusarium oxysporum)的抑菌效果,并通过盆栽试验测定了2株菌共培养发酵液对马铃薯枯萎病的防治效果及对马铃薯相关防御酶活性的影响。结果表明,2株菌单培养和3种比例共培养发酵液对尖孢镰刀菌均有抑制效果且以PT-29与S-16共培养发酵液组合B1T1(比例为1∶1)抑制效果最佳;单培养S-16的发酵液(B)处理对马铃薯枯萎病的防效为60.09%,单培养PT-29的发酵液(T)处理对马铃薯枯萎病的防效为54.85%,B1T1处理对马铃薯枯萎病的防效达到73.44%。此外,B1T1+FO(接种尖孢镰刀菌)处理的马铃薯叶片过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)活性明显高于FO处理,峰值相比于FO处理分别提高56.44%、766.89%、111.84%、179.34%。综上所述,PT-29与S-16共培养发酵液对马铃薯枯萎病的防治效果高于单培养发酵液,为复合微生物防治马铃薯枯萎病提供了理论支持。

SIRT1 inhibits apoptosis of human lens epithelial cells through suppressing endoplasmic reticulum stress in vitro and in vivo

AIM:To explore the effect of silent information regulator factor 2-related enzyme 1(SIRT1)on modulating apoptosis of human lens epithelial cells(HLECs)and alleviating lens opacification of rats through suppressing endoplasmic reticulum(ER)stress.METHODS:HLECs(SRA01/04)were treated with varying concentrations of tunicamycin(TM)for 24h,and the expression of SIRT1 and C/EBP homologous protein(CHOP)was assessed using real-time quantitative polymerase chain reaction(RT-PCR),Western blotting,and immunofluorescence.Cell morphology and proliferation was evaluated using an inverted microscope and cell counting kit-8(CCK-8)assay,respectively.In the SRA01/04 cell apoptosis model,which underwent siRNA transfection for SIRT1 knockdown and SRT1720 treatment for its activation,the expression levels of SIRT1,CHOP,glucose regulated protein 78(GRP78),and activating transcription factor 4(ATF4)were examined.The potential reversal of SIRT1 knockdown effects by 4-phenyl butyric acid(4-PBA;an ER stress inhibitor)was investigated.In vivo,age-related cataract(ARC)rat models were induced by sodium selenite injection,and the protective role of SIRT1,activated by SRT1720 intraperitoneal injections,was evaluated through morphology observation,hematoxylin and eosin(H&E)staining,Western blotting,and RT-PCR.RESULTS:SIRT1 expression was downregulated in TMinduced SRA01/04 cells.Besides,in SRA01/04 cells,both cell apoptosis and CHOP expression increased with the rising doses of TM.ER stress was stimulated by TM,as evidenced by the increased GRP78 and ATF4 in the SRA01/04 cell apoptosis model.Inhibition of SIRT1 by siRNA knockdown increased ER stress activation,whereas SRT1720 treatment had opposite results.4-PBA partly reverse the adverse effect of SIRT1 knockdown on apoptosis.In vivo,SRT1720 attenuated the lens opacification and weakened the ER stress activation in ARC rat models.CONCLUSION:SIRT1 plays a protective role against TM-induced apoptosis in HLECs and slows the progression of cataract in rats by inhibiting ER stress.These findings suggest a novel strategy for cataract treatment focused on targeting ER stress,highlighting the therapeutic potential of SIRT1 modulation in ARC development.

Functionalized selenium nanoparticles ameliorated acetaminophen-induced hepatotoxicity through synergistically triggering PKCδ/Nrf2 signaling pathway and inhibiting CYP 2E1

Selenium nanoparticles(SeNPs)have been demonstrated potential for use in diseases associated with oxidative stress.Functionalized SeNPs with lower toxicity and higher biocompatibility could bring better therapeutic activity and clinical application value.Herein,this work was conducted to investigate the protective effect of Pleurotus tuber-regium polysaccharide-protein complex funtionnalized SeNPs(PTR-SeNPs)against acetaminophen(APAP)-induced oxidative injure in HepG2 cells and C57BL/6J mouse liver.Further elucidation of the underlying molecular mechanism,in particular their modulation of Nrf2 signaling pathway was also performed.The results showed that PTR-SeNPs could significantly ameliorate APAP-induced oxidative injury as evidenced by a range of biochemical analysis,histopathological examination and immunoblotting study.PTR-SeNPs could hosphorylate and activate PKCδ,depress Keap1,and increase nuclear accumulation of Nrf2,resulting in upregulation of GCLC,GCLM,HO-1 and NQO-1 expression.Besides,PTR-SeNPs suppressed the biotransformation of APAP to generate intracellular ROS through CYP 2E1 inhibition,restoring the mitochondrial morphology.Furthermore,the protective effect of PTR-SeNPs against APAP induced hepatotoxicity was weakened as Nrf2 was depleted in vivo,indicating the pivotal role of Nrf2 signaling pathway in PTR-SeNPs mediated hepatoprotective efficacy.Being a potential hepatic protectant,PTR-SeNPs could serve as a new source of selenium supplement for health-promoting and biomedical applications.

UV-B胁迫对辣椒叶片防御酶活性及丙二醛含量的影响

为筛选抗紫外线UV-B辣椒品种,助力青藏高原地区辣椒产业发展,本试验以青海省特色品种青椒3号、循化线椒、甘科-2-11及吉祥101品种为试验材料,研究不同UV-B(20.05μW/cm 2)胁迫时间对辣椒叶片中过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性,以及丙二醛(MDA)含量的影响。结果显示:随着UV-B胁迫时间的延长,POD、CAT及SOD活性均呈现先升高后降低的趋势,于处理第2 d和3 d达到最大,而丙二醛(MDA)含量则呈现先升高后降低再升高的趋势,分别于试验处理第2 d和4 d达到最大。综合以上4个指标,通过隶属函数分析得出4个辣椒品种的耐紫外性依次为青椒3号>循化线椒>甘科-2-11>吉祥101,因此推测青椒3号是耐紫外线强的辣椒品种,适合在青藏高原种植。

巨大芽孢杆菌TA-4的筛选鉴定及对番茄防御酶活性的影响

【目的】筛选具有产生长素(IAA)功能的生防细菌,挖掘其促生潜力。【方法】采用平板稀释和Salkowski法从消毒番茄根际土壤中筛选出具有产IAA功能的细菌,对其中产IAA最多的菌株进行鉴定,并通过盆栽试验测定该菌株对番茄的促生效果及其生物有机肥对番茄过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)和多酚氧化酶(PPO)3种防御酶活性的影响。【结果】菌株TA-4产IAA最多,达39.0μg/mL,经形态学、生理生化和分子生物学方法将其鉴定为巨大芽孢杆菌。盆栽结果表明TA-4生物有机肥能明显促进番茄生长,与未处理对照相比,2%含量TA-4生物有机肥处理番茄30 d的株高、茎粗、鲜重和干重分别增加58.7%、27.3%、53.2%和70.6%。番茄防御酶PAL、PPO和POD活性显著升高,提高了番茄对外界不良环境的抵御能力。【结论】明确了巨大芽孢杆菌TA-4对番茄植株生长及其防御酶活性,为研发新型农用生物有机肥奠定理论基础。

水杨酸对烟草病毒病的防效与烟苗生理活性的影响

【目的】探明喷施水杨酸对烤烟普通花叶病的防效与烟苗生理活性的影响,为水杨酸绿色防控烟草病毒病提供理论依据。【方法】采用漂浮育苗和盆栽试验方法研究喷施不同浓度[T_(1)(0.50 mmol/L)、T_(2)(0.75 mmol/L)和T_(3)(1.0 mmol/L)]水杨酸对烟株病毒病的病情指数和叶片防御酶活性的影响。【结果】喷施不同浓度水杨酸,烟苗叶片的防御酶活性在处理3~6 d时达最高峰;T_(1)和T_(2)防御酶活性和脯氨酸含量较高。其中,POD活性,T_(1)~T_(3)在处理3~6d时较清水对照(CK)分别提高68.00%~74.36%、34.23%~44.22%和4.39%~21.81%。SOD活性,在处理3 d时达最高,较CK分别提高49.47%、65.71%和27.27%。几丁质酶活性,T_(2)在处理3 d时达最高,为925.55 U/g;T_(1)和T_(3)在处理6 d时达最高,分别为1231.75U/g和820.45 U/g,T_(1)较CK提高67.12%。β-1,3-葡聚糖酶活性,均在处理3 d时达最高,较CK分别提高97.12%、59.37%和58.23%。脯氨酸含量,均在处理6 d时达最高,较CK分别提高29.41%、27.71%和17.80%。0.75mmol/L水杨酸处理烟株病毒病的病情指数为26.22,远低于CK(64.80),防控效果达59.53%。【结论】水杨酸可诱导烟叶POD、SOD、几丁质酶、β-1,3-葡聚糖酶活性和脯氨酸含量增加,与烟苗对病毒病的抗性密切相关。

烟草花叶病毒(TMV)免疫诱抗剂的制备与验证

为了制备烟草花叶病毒(TMV)免疫诱抗剂,研究采用壳寡糖、高锰酸钾、内生真菌发酵液、紫外线、银杏叶提取物等试剂处理,筛选出TMV弱毒/无毒株系制备的最优方法,并在室内开展免疫激活效应。结果表明:紫外线、0.1%高锰酸钾溶液、内生真菌发酵液16倍浓缩液、100μg/mL壳寡糖溶液对TMV表现出良好的钝化效果,钝化液对TMV有较高的抑制率。钝化TMV能引起烟草多酚氧化酶(PPO)、过氧化物酶(POD)、超氧化物歧化酶(SOD)、苯丙氨酸解氨酶(PAL)、过氧化氢酶(CAT)5种防御酶活性显著升高,从而提高烟株对TMV感染的抗性。烟苗和大田烟叶TMV防控试验也证明钝化TMV在烟叶生产中可以作为TMV免疫诱抗剂使用,提高烟株的TMV免疫力和抵抗力。

Defensive Responses of Rice Genotypes for Resistance Against Rice Leaffolder Cnaphalocrocis medinalis

The experiment was carried out to assess the reaction of different categories of rice genotypes viz., resistant, susceptible, hybrid, scented, popular and wild in response to the infestation by rice leaffolder （RLF）, Cnaphalocrocis medinalis （Guenee） and to explore the possible use of these genotypes in developing RLF-resistant rice varieties. The changes of various biochemical constituents such as leaf soluble protein, phenol, ortho-dihydroxy phenol, tannin and enzymes viz., peroxidase, phenyl alanine ammonia lyase （PAL） were assessed spectrophotometrically in all the rice genotypes before and after RLF infestation. The protein profile was analyzed using sodium dodecyl sulphate-poly acrylamide gel electrophoresis （SDS-PAGE） method. A significant constituent of biochemical content such as tannin, phenol and ortho-dihydroxy phenol has been increased along with enzyme activities of peroxidase and PAL in the infested resistant （Ptb 33, TKM6 and LFR831311） and wild rice genotypes （Oryza minuta and O. rhizomatis）. A decrease in leaf protein content was evident invariably in all the infested rice genotypes. It is also evident that the contents of biochemicals such as phenol, ortho- dihydroxy phenol and tannin were negatively correlated with leaffolder damage. However, leaf protein content was positively correlated with the damage by rice leaffolder. SDS-PAGE analysis for total protein profiling of healthy and C. medinalis-infested genotypes revealed the enhanced expression of a high molecular weight （〉 97 kDa） protein in all the genotypes. Besides, there was also an increased induction of a 38 kDa protein in C. medinalis infested resistant genotypes, which was absent in uninfested plants. The present investigation proved that the elevated levels of biochemicals and enzymes may play a vital role in rice plants resistance to RLF.