草酸青霉菌果胶酶诱导黄瓜抗黑星病研究

 本文就草酸青霉菌(Penicillium oxalicum)的固态发酵提取产物--果胶酶粗酶液诱导黄瓜对黑星病(Cladosporium cucumerinum)的抗性进行了研究。以果胶酶粗酶液喷雾处理4个感黑星病黄瓜品种的黄化苗,48 h后挑战接种黑星病菌孢子悬液,其中"中农5号"黄瓜品种表现的诱导抗病效果最好,诱抗效果达62.51%。不同浓度果胶酶诱导处理黄瓜,发现果胶酶浓度在20 U/mL时,可导致黄瓜发病略高于对照;在40~200 U/mL浓度范围内,诱导效果较为明显。通过研究果胶酶诱导抗病的时效性,表明诱导处理前接种病菌或诱导处理后0、6 h接种的各处理病情指数与对照间没有差别,而诱导处理12~72 h后接种病菌的,果胶酶的诱导抗病效果均很明显,诱抗效果达29.64%~60.02%。实验还表明,随着挑战接种压力的增大,果胶酶的诱导抗病效果降低。果胶酶不能抑制黑星病菌孢子萌发,相反可以促进孢子萌发和芽管生长。     

碱性果胶酶诱导植物抗病的研究

对碱性果胶酶诱导黄瓜抗病作用进行了研究.结果表明,菌株吉氏芽孢杆菌S-2(B.gibsonii S-2)和克劳氏芽孢杆菌S-4(B.clausii S-4)发酵生产的碱性果胶酶对黄瓜黄化苗具有诱导抗病作用.在不同酶活的处理中,S-2(200 u/ml)和S-4(20u/ml)碱性果胶酶对黄瓜叶和茎上黑星病的病情指数降低最多,其诱导防病效果分别达到73.7%,80.0%和80.6%,86.6%.pH变化对碱性果胶酶的诱导抗病作用影响显著.碱性果胶酶S-2(200 u/ml)和S-4(20 u/ml)在pH 8.0时诱导防病效果较好,它们对黄瓜叶和茎上黑星病的诱导防病效果分别达到64.8%.78.5%和75.0%,87.8%.     

碱性果胶酶诱导黄瓜抗病机理的初步研究

以克劳氏芽孢杆菌(Bacillus clausii)S-4碱性果胶酶诱导黄瓜黄化苗,研究了该激发子对黄瓜生理生化特性的影响,来探究碱性果胶酶诱导黄瓜抗病的机理。结果表明,黄瓜黄化苗经碱性果胶酶诱导后,过氧化物酶、多酚氧化酶和过氧化氢酶活性上升,可溶性蛋白和维生素C含量升高,丙二醛和游离脯氨酸含量下降,活性氧自由基产生速率受到抑制。可见,克劳氏芽孢杆菌S-4碱性果胶酶诱导黄瓜抗病作用与植物体内多种防御相关物质的诱导密切相关。     

黄瓜对炭疽病诱导抗性的初步研究Ⅱ.诱导抗病机制的研究

 黄瓜植株经柑桔炭疽菌(Colletotrichum gloeosporioides)诱导处理后,体内过氧化物酶、多酚氧化酚、苯丙氨酸解氨酶活性均比对照植株有显著增强。过氧化物酶同功酶聚丙烯酰胺凝胶垂直平板电泳(PAGE)表明,经诱导处理后同功酶酶带增多,着色也加深。酚类物质和木质素含量在诱导处理后也明显提高。     

多因子联合诱导系统的构建及对黄瓜白粉病防治试验

由多个不同的抗病诱导因子组成植物抗病诱导系统的1个子系统。每个因子都是这个系统中的1个要素。系统的性质不但取决于系统中的要素,还取决于要素的结构。合理的配伍可以使要素与要素之间、要素与系统之间的关系得以优化,使系统的功能得以强化。把筛选得到的多个不同的抗病诱导因子进行配伍,组合成新的"诱导组合体",其诱导效应比单一因子显著提高;用不同的"诱导组合体"进行"相继诱导"和"循环诱导",则进一步提高诱导效应,对黄瓜白粉病的田间防治效果达到78.16%,高于常规杀菌剂的防治效果。     

两种化合物联合诱导黄瓜对炭疽病的抗病性研究初报

通过用草酸钾和硫酸亚铁2种化合物的8种组合方式,诱导黄瓜对炭疽病的抗病性,证明用两种化合物分别独立诱导和联合诱导均有一定的诱导效应,但联合诱导比独立诱导所获得的诱导效应明显增强.其中,首次用草酸钾诱导,间隔3 d后再用硫酸亚铁进行第2次诱导,所获得的诱导效应最高.田间试验达较好的防治效果.     

玫瑰黄链霉菌活性代谢产物RM诱导黄瓜抗病性的信号转导途径

为明确玫瑰黄链霉菌Streptomyces roseoflavus菌株men-myco-93-63活性代谢产物roflamycoin和men-myco-A(简称RM)诱导黄瓜产生抗病性的信号转导途径,采用高效液相色谱法、分光光度法和实时荧光定量PCR法,测定喷施玫瑰黄链霉菌代谢产物RM后黄瓜叶片中水杨酸含量和脂氧合酶活性,以及水杨酸信号转导途径和乙烯茉莉酸信号转导途径的标志基因——NPR1、PR-1a、CTR1的表达量。结果表明,喷施玫瑰黄链霉菌活性代谢产物RM后120 h,黄瓜叶片内水杨酸含量达到最高值,为7.22μg/g,是对照的1.75倍;喷施玫瑰黄链霉菌活性代谢产物RM后12 h,黄瓜叶片内脂氧合酶活性达到最高值,为52.69 U/g,是对照的1.32倍,并且在120 h内整体活性均高于对照;喷施玫瑰黄链霉菌代谢产物RM后,NPR1和PR-1a基因的相对表达量上调,其最大值分别为0.99和1.35,分别是对照的2.24倍和12.09倍,但抑制CTR1基因的表达。推测玫瑰黄链霉菌代谢产物RM通过水杨酸通路、乙烯通路和茉莉酸通路共同诱导黄瓜抗病性信号转导途径。     

用抗病体子叶SOD同功酶蛋白质诱导黄瓜对霜霉病抗性的研究

 本试验对不同抗霜霉病的黄瓜品种的萌动种子、子叶、不同叶位真叶和感病叶及未感病叶的超氧化物岐化酶(SOD)同功酶进行了电泳分离,并用抗病品种子叶的SO D同功酶带的d带的洗脱液对感病品种进行诱导,探讨其有无诱导免疫效果。     

生物诱抗剂草酸对黄瓜叶片中过氧化物酶的系统诱导作用

 本文进一步证明草酸是一种有效的非生物诱抗剂,它能显著提高黄瓜对炭疽病的系统抗性,进而研究了草酸对黄瓜叶片中与抗病有关的过氧化物酶(POD)的系统诱导作用及其内在机理。结果表明:40mmol/L草酸诱导可溶态POD活性效果最佳;在测定时间范围内,草酸诱导的可溶态POD活性在第7d后逐渐下降,而细胞壁离子键结合态POD活性被诱导后保持稳定;草酸在快带区诱导出一种新的POD同功酶,其Rf值为0.63;自由基清除剂甘露醇和抗坏血酸可明显抑制草酸对可溶态POD活性的诱导作用;草酸诱导可溶态POD的作用信号可在5h左右从被处理的第1片真叶传导至未处理的第2片真叶,被处理叶的保留时间越长,其诱导效果越好。     

病原菌诱导黄瓜对其主要病害的抗病反应

以5种黄瓜主要病原菌作为诱导抗病因子,研究其对黄瓜主要病害的作用,结果发现黄瓜经病原菌诱导后,可以产生对诱导病原菌及其它病原菌引起病害的交互保护作用,并且诱导的交互保护作用与诱导浓度、诱导间隔期、不同品种存在相关性.诱导效果不随诱导接种浓度的升高而升高.在黑星病菌对霜霉病菌的诱导作用中,以浓度为1×102个/ml的黑星病菌孢子悬浮液的诱导效果最好,诱导间隔期为48h黄瓜黑星病菌对霜霉病的交互保护作用最明显,抗性品种的交互保护作用明显好于感病品种;炭疽病菌可诱导黄瓜有效抑制褐斑病的发生,但挑战接种褐斑病菌后,却促进了炭疽病的发生.诱导接种炭疽病菌后再挑战接种褐斑病菌12d,对褐斑病的防效为92.07%.     

20%腈菌唑·福美双可湿性粉剂防治黄瓜黑星病药效试验

本文报道了20%腈菌唑·福美双可湿性粉剂对黄瓜黑星病的田间防治效果和使用方法。结果表明:在黄瓜发病初期施药,可取得较好的防效,以每亩100～130g的用量对黄瓜黑星病的防效可达70.88%～80.5%。     

内生菌醇提取物对水稻抗稻瘟病的诱导作用

本文研究内生菌醇提取物WS对水稻稻瘟病的诱导抗性,在水稻3叶1心期喷施3种浓度WS,通过诱导抗病效果筛选WS最佳使用浓度,同时研究最佳浓度对水稻相关抗病防御酶活性的影响.结果表明,浓度50 ng/mL WS喷雾处理时诱导抗病效果最佳,病情指数降低12.89,诱导效果达到55.5％.能够显著提高PAL、PPO、几丁质酶活性,PAL活性高于CK处理30.28％,PPO、几丁质酶活性分别是CK处理的1.18、1.70倍.     

Induced Resistance of Acibenzolar-S-methyl (CGA 245704) to Cucumber and Japanese Pear Diseases

Antifungal activity of the novel compound acibenzolar-S-methyl (CGA245704: benzo[1,2,3]thiadiazole-7-carbothioic acid S-methyl ester) was examined in vitro. No remarkable activity was observed on mycelial growth and conidial germination of almost all fungi tested. Only melon isolates of Didymella bryoniae were sensitive to this compound. On potted plants, acibenzolar-S-methyl showed control efficacy on anthracnose and scab of cucumber and rust of Japanese pear but not on Fusarium wilt of cucumber. In field trials, the occurrence of both rust and scab on Japanese pear was suppressed with this compound. Based on these experiments, it was suggested that acibenzolar-S-methyl induced resistance to some but not all diseases on cucumber and Japanese pear. Induction of disease resistance in cucumber was rapidly triggered after treatment with acibenzolar-S-methyl.     

Searching by Differential Display for New Genes Implicated in Induced Disease Resistance of Cucumber Treated with Acibenzolar-S-methyl

Acibenzolar-S-methyl (ASM) is a chemical activator of systemic disease resistance in plants. In this study, we used differential display to identify ASM-inducible defense response genes involved in induced disease resistance. As a result, we cloned three ASM-inducible genes from cucumber, encoding a chitinase, a putative protein disulfide isomerase and a putative mitochondrial-protein-like protein. Expression of these genes was induced within 24 hr after treatment of cucumber leaves with ASM. These results suggest that differential display is a useful tool for understanding the mode of action of ASM and defense responses. Received 6 September 2000/ Accepted in revised form 11 April 2001     

三种化学物质诱导观赏百合青霉病抗性的研究

采用水杨酸、纳米硅、氯化铵等3种化学物质对观赏百合青霉病的抑菌活性和诱抗效果进行了测定。结果表明,3种化学物质对观赏百合青霉病菌抑菌率较低,最高仅为5.6%。3种化学物质处理百合鳞茎后,表现出较高诱导抗病性。在100、50和25μg/ml浓度下,水杨酸的诱导抗病效果最好,分别为79.09%、69.28%和61.96%。浓度为100μg/ml的水杨酸、纳米硅和氯化铵处理观赏百合鳞茎后,再进行挑战接种,1d后鳞茎组织内过氧化物酶、苯丙氨酸解氨酶、β-1,3-葡聚糖酶活性明显高于对照。浓度为100μg/ml的3种化学物质处理百合种球在2℃条件下贮存4个月后,青霉病的发病率和病情指数均低于对照;水杨酸、纳米硅和氯化铵处理的诱导防治效果分别为60.89%、55.56%和35.31%;处理种球种植后能够正常萌发,出苗率分别为91.67%、90.83%、90.83%。     

Induced Resistance in Hypocotyl of Cucumber by Infection with Colletotrichum lagenarium in Leaves

Localized infection of cucumber leaves with Colletotrichum lagenarium induced resistance against infection after challenge inoculation with pathogenic fungi, including C. lagenarium and Pythium ultimum var. ultimum. Systemic acquired resistance in the hypocotyl was observed when challenge inoculation was made 4 to 7 days after the first inoculation of cotyledons. Seven days after the first inoculation of a primary leaf, induced resistance against the challenge inoculation in the hypocotyl was also observed. However, the hypocotyl did not develop induced resistance when plants were challenged by a wound inoculation with P. ultimum. Received 9 June 1999/ Accepted in revised form 13 December 1999     

Application of Rhizobacteria for Induced Resistance

This article provides a review of experiments conducted over a six-year period to develop a biological control system for insect-transmitted diseases in vegetables based on induced systemic resistance (ISR) mediated by plant growth-promoting rhizobacteria (PGPR). Initial experiments investigated the factors involved in treatment with PGPR led to ISR to bacterial wilt disease in cucumber caused by Erwinia tracheiphila. Results demonstrated that PGPR-ISR against bacterial wilt and feeding by the cucumber beetle vectors of E. trachiphiela were associated with reduced concentrations of cucurbitacin, a secondary plant metabolite and powerful beetle feeding stimulant. In other experiments, PGPR induced resistance against bacterial wilt in the absence of the beetle vectors, suggesting that PGPR-ISR protects cucumber against bacterial wilt not only by reducing beetle feeding and transmission of the pathogen, but also through the induction of other plant defense mechanisms after the pathogen has been introduced into the plant. Additional greenhouse and field experiments are described in which PGPR strains were selected for ISR against cucumber mosaic virus (CMV) and tomato mottle virus (ToMoV). Although results varied from year to year, field-grown tomatoes treated with PGPR demonstrated a reduction in the development of disease symptoms, and often a reduction in the incidence of viral infection and an increase in tomato yield. Recent efforts on commercial development of PGPR are described in which biological preparations containing industrial formulated spores of PGPR plus chitosan were formulated and evaluated for use in a transplant soil mix system for developing plants that can withstand disease attack after transplanting in the field.     

Induction of Systemic Resistance in Cucumber against Several Diseases by Plant Growth-promoting Fungi: lignification and Superoxide Generation

Five fungal isolates (Trichoderma, Fusarium, Penicillium, Phoma and a sterile fungus) from zoysiagrass rhizosphere that promote plant growth were tested for their ability to induce systemic resistance in cucumber plants against Colletotrichum orbiculare. Roots of cucumber plants were treated with these fungal isolates using barley grain inocula (BGI), mycelial inocula (MI) or culture filtrate (CF). Most isolate/inoculum form combinations significantly reduced the disease except BGI of Trichoderma. These fungal isolates were also evaluated for induction of systemic resistance against bacterial angular leaf spot and Fusarium wilt by treatment with BGI. Penicillium, Phoma and the sterile fungus significantly reduced the disease incidence of bacterial angular leaf spot. Phoma and sterile fungus protected plants significantly against Fusarium wilt. Roots treated with CFs of these fungal isolates induced lignification at Colletotrichum penetration points indicating the presence of an elicitor in the CFs. The elicitor activity of CFs was evaluated by the chemiluminescence assay using tobacco callus and cucumber fruit disks. The CFs of all isolates elicited conspicuous superoxide generation. The chemiluminescence activity of the CF of Penicillium was extremely high, and its intensity was almost 100-fold higher than that of other isolates. The chemiluminescence activity was not lost following treatment with protease or autoclaving or after removal of lipid. The MW 12,000 dialyzed CF fraction was highly effective in eliciting chemiluminescence activity. Chemiluminescence emission from cucumber fruit disks treated with Penicillium was the same as that obtained from tobacco callus, except that the lipid fraction also showed a high activity. Both the MW 12,000 fraction and the lipid fraction induced lignification in the epidermal tissues of cucumber hypocotyls.