亚精胺诱导黄瓜幼苗对白粉病抗性的研究

以黄瓜品种‘长春密刺’幼苗为材料,研究了亚精氨(Spd)诱导黄瓜幼苗对白粉病的抗性,并测定Spd处理和白粉菌接种对黄瓜叶片4种防御酶活性及3种防卫基因表达的影响。结果显示:(1)0.2～1.0mmol.L-1 Spd对黄瓜幼苗白粉病抗性均有不同程度的诱抗效果,并以0.8mmol.L-1 Spd处理效果最明显,诱导效率可达55.3%。(2)喷施Spd或接种白粉菌均可提高黄瓜叶片过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)、几丁质酶和β-1,3-葡聚糖酶的活性,且诱导并接种处理的植株叶片上述酶活性均比只诱导不接种处理的上升速度更快;同时,Spd处理和接种白粉菌可以提高植株叶片中POX、PAL、PR-1a基因的表达量。研究表明,Spd处理可以诱导防卫基因表达的增强,提高防御酶活性,显著降低病情指数,增强黄瓜幼苗对白粉病的抗性。     

外源Spd预处理对甜瓜白粉病抗性及其内源多胺的诱导分析

以甜瓜感病品种‘0544’为试材,测定外源亚精胺(Spd)预处理和白粉病菌接种后甜瓜幼苗的光合参数、抗氧化酶活性、内源多胺含量及多胺合成与代谢相关基因表达等的变化,探讨外源Spd处理对甜瓜幼苗白粉病抗性的诱导作用机制。结果显示:(1)1.0mmol·L-1外源Spd处理可显著降低甜瓜幼苗的白粉病病情指数,缓解植株发病症状;(2)外源Spd处理可诱导甜瓜幼苗的多胺合成以及代谢相关基因(SAMDC、ADC、ODC、Spd、Spm、PAO)显著上调表达;(3)外源Spd处理可诱导甜瓜幼苗腐胺(Put)和Spd含量显著增加,而外源Spd并接种白粉病菌处理对甜瓜幼苗精胺(Spm)含量积累的诱导更加显著;(4)接种白粉病菌诱导了甜瓜幼苗的多酚氧化酶(PPO)、过氧化物酶(POD)和超氧化物歧化酶(SOD)的活性,外源Spd预处理后再接种白粉病的诱导作用更大,同时外源Spd处理还诱导了甜瓜幼苗过氧化氢(H_2O_2)含量的升高;(5)在观测期(120h)内,接种白粉病菌对甜瓜叶片的光合作用抑制较小,而外源Spd预处理并接种白粉病菌共同诱导了甜瓜幼苗的光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)的显著升高。研究认为,在外源Spd预处理甜瓜幼苗后再接种白粉病菌,甜瓜幼苗可以通过多胺的快速积累及代谢产生的H_2O_2来启动响应机制,进而通过增强防御酶活性等途径来提高对白粉病的抗性。     

Induction of Systemic Resistance to Tobacco Powdery Mildew by Tobacco Mosaic Virus, Tobacco Necrosis Virus or Ethephon

Local infections of either TMV or TNV in tobacco plants cv. Havana 425 (hypersensitive to TMV) proved effective in inducing systemic resistance to subsequent inoculation with the powdery mildew fungus Erysiphe cichoracearum DC. The proportion of leaf surface invaded by this pathogen and the amount of conidia it produced were both significantly lower in virus inoculated plants than in non-inoculated controls. However, the decrease in sporulation rate was less regularly observed than the reduction in leaf area infected. TMV was more effective than TNV in protecting tobacco plants from powdery mildew. E. cichoracearum is thus added to the list of challenge pathogens to which TMV or TNV are known to induce resistance in the host plants. Necrotic lesions caused to the leaves by local treatment with Ethephon (an ethylene-releasing compound) also conferred to tobacco some degree of systemic resistance to the same fungal pathogen, more frequently visible as a reduction of leaf area invaded. The protection due to the Ethephon lesions was in present experiments less marked than that of TMV. No effects against subsequent powdery mildew infection were obtained when point freeze necrotic lesions were provoked on the plants.     

外源亚精胺对甜瓜幼苗白粉病抗性的影响

以高感白粉病甜瓜‘066’、感病品种‘0544’、抗病品种‘Yuntian-930’为试材,对白粉病菌胁迫下外源亚精胺（Spd）处理的甜瓜幼苗叶片超氧化物岐化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）和多酚氧化酶（PPO）活性,以及过氧化氢（H₂O₂）、丙二醛（ MDA）和光合色素含量进行了研究,探讨外源Spd对甜瓜白粉病抗性的诱导效应及其生理机制。结果表明：（1）白粉病菌接种后甜瓜叶片的防御酶活性、光合色素含量先升后降,MDA含量升高;（2）外源Spd处理缓解了白粉病菌胁迫下甜瓜叶片防御酶活性、光合色素含量的下降,降低MDA含量及甜瓜的病情指数,并以1.0 mmol/L Spd处理效果最佳;（3）外源Spd处理使甜瓜叶片产生了更多的H₂O₂;（4）外源Spd提高甜瓜对白粉病抗性具有一定广谱性,且可向上传导。研究认为,H₂O₂可能参与白粉病胁迫下信号的传递,外源Spd可通过缓解白粉病菌胁迫下甜瓜防御酶活性和光合色素含量的下降来诱导甜瓜对白粉病的抗性。     

Induction of Salicylic Acid {beta}-Glucosidase in Tobacco Leaves by Exogenous Salicylic Acid

Salicylic acid (SA) has been proposed to be an endogenous signalfor systemic acquired resistance to infection by pathogens inplants. In general, most SA is found in an inactive form asSA ß-glucoside (SAG). SAG seems to be a storage formof SA from which bioactive SA can be generated. Recent reportsindicate that ß-glucosidase might be involved in regulatingthe signaling activity of phytohormones. Therefore, it seemslikely that SA ß-glucosidase, the enzyme that hydrolyzesSAG to yield free SA, might also play an important role by regulatingthe level of free SA. Since hydrolysis of SAG seems to occurin intercellular spaces, we attempted to isolate SA ß-glucosidaseactivity from the intercellular spaces of SA-treated tobaccoleaves, where we found considerable amounts of the enzymaticactivity. Furthermore, increased levels of SA and SA ß-glucosidaseactivity were found in the leaves after treatment with exogenousSA. The role of SA ß-glucosidase in plant defensesystems is discussed. (Received November 15, 1994; Accepted January 20, 1995)     

水杨酸对苦瓜叶片白粉病抗性及抗氧化酶活性的影响

以‘碧绿3号’苦瓜幼苗为材料,采用100、500和1000μmol.L-1的水杨酸(SA)溶液预处理后进行白粉菌的诱导接种,研究了SA处理对苦瓜叶片光合色素含量和4个抗氧化酶活性的影响。结果显示:各浓度SA处理苦瓜植株的病情指数均显著低于对照(蒸馏水处理),并随SA处理浓度增加而逐渐下降;各SA处理苦瓜叶片的光合色素含量均高于其对照,且随SA处理浓度升高而逐渐增加;苦瓜叶片APX、CAT和GR活性随SA处理浓度增加而升高,但GPX活性反而下降,各处理CAT和GR活性增幅均高于病情指数增幅,1000μmol.L-1SA处理的APX活性增幅也高于病情指数增幅。研究发现,SA处理可以提高苦瓜感染白粉病植株叶片的光合色素含量及其抗氧化酶活性,显著降低其病情指数,增强其白粉病抗性,且以1000μmol.L-1SA处理效果最好。     

Induction of Systemic Acquired Resistance in Pea against Rust (Uromyces pisi) by Exogenous Application of Biotic and Abiotic Inducers

Pea breeding for rust resistance is hampered by the little resistance available in pea. In an attempt to validate alternative control methods, we evaluated the potential of systemic acquired resistance for rust control in pea by biotic and abiotic inducers. Challenge with a virulent or with an avirulent rust isolate prior to pea rust inoculation did not induce resistance either locally or systemically. Exogenous application of salicylic acid in the range 5–10 m m prior to rust inoculation did not protect against rust locally, but reduced rust infection systemically in first upper leaf node although not in the upper ones. Some phytotoxicity was observed at 10 m m . Exogenous application of benzothiadiazole in the range 1–10 m m provided locally a 30–40% reduction in infection frequency. At least 5 m m was needed to reduce rust infection systemically in first upper leaf, and 10 m m in upper ones. Exogenous application of dl -3-amino- n -butyric acid (BABA) provided locally a 45–58% reduction in infection frequency, while systemically a 33–58 and 49–58% reduction of rust symptoms was achieved on leaves at second and third nodes respectively. BABA application was not associated with symptoms of phytotoxicity.     

HydroxyproUne-rich Glycoprotein Accumulation in TMV-infected Tobacco Showing Systemic Acquired Resistance to Powdery Mildew

Tobacco cv. Havana 425, with systemic-acquired resistance (SAR) to an otherwise compatible Erysiphe cicho-racearum DC. race after TMV infection, was infected with TMV basaily (4^th and 5^th leaves) and the hydroxyproline-rich glycoproteins (HRGPs) were determined in two experiments (experiment 1 and experiment 2) by analysing cell wall hydroxyproline (Hyp) in the 6^th leaf. In basal TMV infected plants Hyp content (μmol^-1 FW) was greater than in controls in both experiments: the increase was significant at all times except 16 days after TMV inoculation in experiment 1; the pool of data of experiment 2 was also significantly increased. In TMV protected + E. cichoracearum challenged leaves compared to untreated controls significant increases in Hyp were also noted between the pools of data in both experiments. No differences were found between Hyp content in protected compared to protected + challenged leaves in both experiments. These results show accumulation of HRGPs in Havana tobacco associated with TMV infection and SAR activation against E, cichoracearum. The accumulation appears to be due to the inducer, since no further increase was detected in protected leaves after challenging.     

Regulation of Salicylic Acid and N-Hydroxy-Pipecolic Acid in Systemic Acquired Resistance

In plants, salicylic acid (SA) is a central immune signal that is involved in both local and systemic acquired resistance (SAR). In addition to SA, several other chemical signals are also involved in SAR and these include N-hydroxy-pipecolic acid (NHP), a newly discovered plant metabolite that plays a crucial role in SAR. Recent discoveries have led to a better understanding of the biosynthesis of SA and NHP and their signaling during plant defense responses. Here, I review the recent progress in role of SA and NHP in SAR. In addition, I discuss how these signals cooperate with other SAR-inducing chemicals to regulate SAR.     

水杨酸对水稻防卫反应酶系的系统诱导（简报）

经 10 .0 μg·ml-1水杨酸 (SA)喷雾处理后稻苗叶片中苯丙氨酸解氨酶 (PAL)、过氧化物酶 (PO)和多酚氧化酶 (PPO)活性都迅速增强 ,处理后 12～ 2 4h达到高峰。未经SA处理的叶片中PAL、PO和PPO酶活性则在处理后 4 8h达到高峰 ,且活性增加明显低于SA处理的叶片。处理和未处理叶片中木质素含量都迅速增加。这些生理指标的时序变化与SA诱导稻苗抗白叶枯病的表现基本吻合。     

加拿大豌豆品种（系）抗白粉病表型和基因型鉴定

对36个引自加拿大的豌豆品种(系)进行抗白粉病表型和标记基因型鉴定,明确了豌豆品种Cooper和Tara白粉病抗性等位基因。苗期接种了2个不同地理来源的豌豆白粉病菌分离物,32个品种(系)对2个分离物均表现为免疫;品系MP1818-2对云南白粉菌分离物EPYN免疫,但对北京分离物EPBJ感病;其余3个品种对2个分离物均感病。4个与豌豆抗白粉病基因er1连锁的SCAR标记将36个豌豆品种(系)区分为5个标记基因型。与野生型PsMLO1基因序列比较发现,豌豆品种Cooper和Tara的PsMLO1候选基因均在680 bp处发生C变G的单核苷酸突变。     

大麦种质资源白粉病抗性鉴定与应用

为了充分利用抗病大麦种质资源,对本所多年来征集的921份国内外大麦品种资源进行白粉病田间自然鉴定.结果表明,田间表现高抗品种有181个,占总数19.65%,抗病品种163个,占总数17.70%;表现感病品种有447个,占总数的48.53%,高感品种130个,占总数14.12%.通过品种的全生育期、株高、穗长、穗实粒数、结实率、穗粒重和千粒重等7个主要农艺性状的分析表明,181个高抗种质主要农艺性状均存在较大的遗传分化.本文还对抗病种质木石港3号、植3和S-096等在育种中的应用进行了阐述.     

Genetics of Powdery Mildew Resistance in Barley

A comprehensive, critical review on the present knowledge regarding the genetics of resistance of barley to the powdery mildew fungus is presented. The review deals with six kinds of resistance: Race-specific resistance; Mlo resistance; partial resistance; induced resistance; passive resistance; and non-host resistance. Most of the sections are subdivided into: phenotype of the interaction; resistance mechanisms; and genetics. A distinction is made between three groups of genes involved in the defense of plants to diseases: those that serve exclusively to mediate resistance; those that are mobilized to strengthen the plants' defense; and those that serve exclusively functions other than disease defense, but may bring about resistance. The more than 200 gene symbols assigned to race-specific mildew resistance genes over time are summarized and revised to 85 symbols that may be considered valid.     

Resistance Induction by Salicylic Acid Formulation in Cassava Plant against Fusarium solani

Fusarium root rot caused by the soil-borne fungus Fusarium solani is one of the most important fungal diseases of cassava in Thailand, resulting in high yield losses of more than 80%. This study aimed to investigate if the exogenous application of salicylic acid formulations (Zacha) can induce resistance in cassava against Fusarium root rot and observe the biochemical changes in induced cassava leaf tissues through synchrotron radiation based on Fourier-transform infrared (SR-FTIR) microspectroscopy. We demonstrated that the application of Zacha11 prototype formulations could induce resistance against Fusarium root rot in cassava. The in vitro experimental results showed that Zacha11 prototype formulations inhibited the growth of F. solani at approximately 34.83%. Furthermore, a significant reduction in the disease severity of Fusarium root rot disease at 60 days after challenge inoculation was observed in cassava plants treated with Zacha11 at a concentration of 500 ppm (9.0%). Population densities of F. solani were determined at 7 days after inoculation. Treatment of the Zacha11 at a concentration of 500 ppm resulted in reduced populations compared with the distilled water control and differences among treatment means at each assay date. Moreover, the SR-FTIR spectral changes of Zacha11-treated epidermal tissues of leaves had higher integral areas of lipids, lignins, and pectins (1,770–1,700/cm), amide I (1,700–1,600/cm), amide II (1,600–1,500/cm), hemicellulose, lignin (1,300–1,200/cm), and cellulose (1,155/cm). Therefore, alteration in defensive carbohydrates, lipids, and proteins contributed to generate barriers against Fusarium invasion in cassava roots, leading to lower the root rot disease severity.     

Biochemical and Physiological Response to Salicylic Acid in Relation to the Systemic Acquired Resistance

In five genotypes of cowpea (Vigna unguiculata), the influence of salicylic acid (SA) on photosynthetic activity and biochemical constituents including peroxidase activity at the genotypic level was determined. After SA treatment the total free sugar content increased in IFC 8401 and IGFRI 450 genotypes, whereas the content of total leaf soluble proteins decreased significantly in IFC 902. The high chlorophyll (Chl) (a + b) content in IFC 902 showed a good correlation with the net photosynthetic rate (PN), as in this genotype a significant increase in PN was found after the SA treatment.