咖啡酸和氯化钴对茉莉酸甲酯诱导抗病相关酶活性的影响

烟草愈伤组织在含咖啡酸(5mmol/L)和／或CoCl2(10mmol/L,乙烯合成抑制剂)的MS培养基上暗培养,同时用莱莉酸甲酯(1mg／d,简称MJ)处理愈伤组织。处理后测定乙烯、水杨酸和病程相关蛋白(PR)含量及一些抗病相关酶活性。MJ明显促进乙烯产生、增加水杨酸和PR蛋白含量,提高苯丙氨酸解氨酶(PAL)、β1,3—葡聚糖苷酶和几丁酶的活性。咖啡酸降低MJ对乙烯和水杨酸诱导,CoCl2明显降低MJ对乙烯的诱导,但没有明显影响MJ对水杨酸的诱导,两者都促进MJ诱导PAL活性而抑制MJ诱导β1,3—葡聚糖苷酶活性。咖啡酸明显影响MJ诱导内切几丁酶,几乎完全抑制对外切几丁酶的诱导;CoCl2对MJ诱导内切几丁酶没有影响,促进对外切几丁酶的诱导。实验结果表明,不同的抗病相关酶活性诱导有不同的信号传递途径,在所测几种酶的诱导中,水杨酸起主要作用,乙烯作用较小,MJ的诱导作用主要是由水杨酸所转导。     

氨基茚磷酸(AIP)和氨基氧乙酸(AOA)对茉莉酸甲酯诱导的烟草一些酶活性的影响

用茉莉酸甲酯(MJ,1mg ml^-1)处理培养在含0．1mmol／L AIP(水杨酸合成抑制剂)和／或1mmol／L AOA(乙烯合成抑制剂)的MS培养基上的烟草愈伤组织,测定某些酶的活性。结果表明：MJ明显提高过氧化物酶(POD)、β1,3-葡聚糖苷酶和几丁质外切酶的活性,略微促进苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)的活性,抑制几丁内切酶的活性,而AOA和AIP则明显抑制MJ对POD和β1,3-葡聚糖苷酶活性的诱导作用,但对MJ诱导的PAL和PPO的活性影响很小,AOA和AIP可能作为逆境因子促进PAL的活性。AOA能部分解除MJ对几丁内切酶的抑制作用,但对MJ诱导的几丁外切酶的影响较小,而AIP抑制几丁内切酶的活性,也抑制MJ对此酶的诱导作用。因此我们认为：MJ对POD、PPO和几丁内切酶的影响可能是通过乙烯途径,对β1,3-葡聚糖苷酶和几丁外切酶的影响可能是通过水杨酸(SA)途径,而对PAL的影响可能是通过其它途径。     

新疆甜瓜经疫霉菌毒素诱导后酶活性的变化（简报）

抗病性不同的新疆甜瓜品种经疫霉菌毒素诱导后,PAL活性在总体上呈上升趋势,且与品种的抗感病程度的顺序一致;POD活性初期下降,8h后开始上升,24h达最大值,随后下降;几丁内切酶与几丁外切酶的第一活性峰均出现在诱导后16h,而第二活性峰出现的时间团品种抗病性差异而不同;β-1,3-葡聚糖酶的活性变化与几丁质酶基本一致。     

香蕉采后炭疽病发生与几丁酶、β-1,3-葡聚糖酶和多巴胺的关系

几丁酶、β－1,3-葡聚糖酶随着香蕉术后炭疽病的发展过程,活性逐渐增加;但当果实出现明显病害症状时活性略有下降。施保功处理在抑制香蕉采后炭疽病发生的同时也抑制了芭蕉炭疽菌可能诱导的几丁酶和β-1,3-葡聚糖酶活性的增加。多巴胺在香蕉采收时含量较高,但随着炭疽病的发生明显下降。对“黑油身”和“63－1”两个不同抗病品种分析表明,前者几丁酶和β－1,3-葡聚糖酶活性和多巴胺含量较高与其较强的抗病性相一致。     

BTH对小麦叶片防卫相关酶的系统诱导作用

用0.4 mmol/L的苯并噻二唑(BTH)溶液处理小麦幼苗第1叶和第2叶2 d后接种白粉菌,比色法测定第3叶接种前后过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)、几丁质酶和β-1,3-葡聚糖酶的活性,结果表明BTH处理或接种均可使这4种酶活性升高。BTH诱导酶活性的系统增强与小麦对白粉病的诱导抗性密切相关。     

茉莉酸甲酯对烟草幼苗抗病毒的影响

用茉莉酸甲酯处理4叶期烟草(Nicotiana tabacum L.)幼苗后接种烟草花叶病毒,考察发病情况和病情指数,并测定一些与抗病相关的酶活性。结果表明,茉莉酸甲酯处理后接种病毒明显降低巴两烟草的病情指数,提高几丁内切酶、β1,3-葡聚糖苷酶、SOD、脂氧酶的活件。其中仅SOD活性与抗病毒有较密切的关系。茉莉酸甲酯可能是诱导巴西烟草抗花叶病毒的信号物质。     

水杨酸和黄萎病菌毒素处理棉花愈伤组织使β-1,3-葡聚糖酶和几丁质酶的活性增加

不同品种棉花(Gossypium hirsutum L.)愈伤组织对黄萎病菌毒素粗提物的抗性与体内β-1,3-葡聚糖酶和几丁质酶活性水平有关.在毒素处理下,抗性品种比感性品种酶活性增加的幅度大、时间早.外源水杨酸(SA)处理后,棉花愈伤组织中的β-1,3-葡聚糖酶和几丁质酶活性增加.抗β-1,3-葡聚糖酶多克隆抗体与28 kD的蛋白条带有免疫交叉反应,毒素、SA、毒素+SA均能诱导该蛋白条带出现.     

两种水杨酸代谢相关酶在逆境龙须菜中的活性研究

旨在探索水杨酸(Salicylic acid,SA)信号通路相关的两种酶——苯丙氨酸解氨酶(PAL)和β-1,3-葡聚糖酶(β-1,3-GA)在病烂、盐度、温度逆境和添加SA条件下在龙须菜中的活性变化。结果表明,3组病烂龙须菜中PAL和β-1,3-GA活性分别增加为对照组的1.27-1.42倍和1.26-1.35倍;高盐条件下PAL活性与对照组无显著差别,而β-1,3-GA活性在24 h和48 h分别增加为对照组的1.90倍和1.42倍;高温组PAL和β-1,3-GA活性在24 h均显著升高,分别是对照组的1.25倍和1.27倍;100μmol/L SA添加后PAL和β-1,3-GA的活性升高,但高浓度SA却抑制了两种酶的活性。结果表明,在逆境胁迫下龙须菜中PAL和β-1,3-GA的活性增加与水杨酸的抗逆作用有关,而100μmol/L SA诱导两种酶的效果最显著。     

毛头鬼伞多糖对烟草酶活性和同工酶谱的影响

分析了毛头鬼伞(Coprinus comatus)真菌多糖诱导烟草对烟草花叶病毒(TMV)抗性过氧化物酶(POD)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)、几丁质酶、-β1,3-葡聚糖酶活性的变化。结果表明,毛头鬼伞多糖可提高POD、PPO、PAL、几丁质酶和-β1,3-葡聚糖酶的活性,接种TMV后毛头鬼伞多糖处理的烟草酶活性显著高于不处理者。上述结果提示,毛头鬼伞多糖处理后烟草酶活性的增强可能与其诱导烟草获得抗性有关。     

茉莉酸甲酯对烟草愈伤组织一些活性氧生成和相关酶活性的影响

烟草愈伤组织用茉莉酸甲酯(MJ, 1mgml-1)处理;同时将愈伤组织在含AIP(0.1mmol/L,水杨酸合成抑制剂)和/或AOA(1mmol/L,乙烯合成抑制剂)的MS培养基上进行暗培养,测定在活性氧产生和脂质过氧化中起作用的相关酶活性及一些代谢物的含量。结果表明,茉莉酸甲酯能激活超氧阴离子的产生,提高脂氧合酶同工酶1(LOX1)的活性从而启动脂质过氧化,对脂氧合酶同工酶3(LOX3)没有明显影响;降低过氧化氢(H2O2)的含量、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)及抗坏血酸过氧化物酶(APX)等保护酶的活性,减少了膜脂过氧化中有毒物质丙二醛(MDA)的含量。AIP和AOA都对MJ的作用有不同程度的影响。MJ调节超氧阴离子和过氧化氢生成以及相关酶活性是通过不同的信号转导途径,MJ调节超氧阴离子和MDA生成、SOD和APX活性很可能是通过乙烯起作用,且对MDA生成和APX活性的调节可能通过水杨酸起作用;MJ直接调节LOX1活性,但对LOX3活性没有明显作用。     

Effect of salicylic acid and methyl jasmonate on antioxidant systems of <Emphasis Type="Italic">Haematococcus pluvialis</Emphasis>

The influence of phytohormones, salicylic acid (SA) and methyl jasmonate (MJ) on the antioxidant systems in Haematococcus pluvialis was investigated. Both SA and MJ at 500 μM concentration reduced the growth of alga with salicylic acid, having more pronounced effect. Carotenoid and chlorophyll contents were decreased by SA and increased by MJ. Salicylic acid (100 μM) increased astaxanthin content to 6.8-fold under low light (30 μmol m⁻² s⁻¹), while MJ (10 μM) showed marginal increase in astaxanthin. Salicylic acid (500 μM) increased superoxide dismutase activity to 4.5- and 3.3-fold and ascorbate peroxidase (APX) activity to 15.5- and 7.1-fold under low and high light, respectively. Methyl jasmonate increased catalase activity (1.4-fold) under high light and APX activity (5.4-fold) under low light. Different mechanism of oxidative stress induced antioxidant production may be the plausible reason for this varied response for salicylic acid and methyl jasmonate. Higher concentrations of SA and MJ inhibited astaxanthin accumulation by different mechanisms either by scavenging the free radicals or by increasing primary carotenoids production. At lower concentrations, these phytohormones could be used for elicitation of secondary carotenoid production.     

Involvement of secondary metabolites and extracellular lytic enzymes produced by Pseudomonas fluorescens in inhibition of Rhizoctonia solani, the rice sheath blight pathogen

Fourteen strains of Pseudomonas fluorescens isolated from rhizosphere soil of rice were tested for their antagonistic effect towards Rhizoctonia solani, the rice sheath blight fungus. Among them, PfMDU2 was the most effective in inhibiting mycelial growth of R. solani in vitro. Production of chitinase, beta-1,3-glucanase, siderophores, salicylic acid (SA) and hydrogen cyanide (HCN) by P. fluorescens strains was evaluated. The highest beta-1,3-glucanase activity, siderophore production, SA production and HCN production were recorded with PfMDU2. A significant relationship between the antagonistic potential of P. fluorescens against R. solani and its level of beta-1,3-glucanase, SA and HCN was observed.     

Increase of β-1, 3-Glucanase and Chitinase Activities in Cotton Callus Cells Treated by Salicylic Acid and Toxin of Verticillium dahliae

The different resistance of cotton (Gossypium hirsutum L.) cultivars to crude toxin of Verticillium dahliae (VD) was correlated with the activities of chitinase and β-1, 3-glucanase in callus cells. The activities of chitinase and β-1, 3-glucanase in the callus cells treated with the VD-toxin were increased to the higher level at earlier time point in resistant cultivars than these in the susceptible cultivars. Exogenous salicylic acid (SA) induced the accumulation of chitinase and β-1,3-glucanase, which resulted in the resistance of callus cells to the VD. toxin. Western blot using a polyclonal antibody against β-1,3-glucanase identified 28 kD protein that was induced by VD-toxin, SA, or VD-toxin plus SA.     

Salicylic acid and methyl jasmonate improve chilling tolerance in cold-stored lemon fruit (Citrus limon)

Chilling injury (CI) is associated with the degradation of membrane integrity which can be aligned to phenolic oxidation activated by polyphenol oxidase (PPO) and peroxidase (POD), enzymes responsible for tissue browning. Phenylalanine ammonia-lyase (PAL) is a further enzyme prominent in the phenolic metabolism that is involved in acclimation against chilling stress. It was hypothesized that treatment with methyl jasmonate (MJ) and salicylic acid (SA) may enhance chilling tolerance in lemon fruit by increasing the synthesis of total phenolics and PAL by activating the key enzyme regulating the shikimic acid pathway whilst inhibiting the activity of POD and PPO. Lemon fruit were treated with 10 μM MJ, 2 mM SA or 10 μM MJ plus 2 mM SA, waxed, stored at −0.5, 2 or 4.5 °C for up to 28 days plus 7 days at 23 °C. Membrane integrity was studied by investigating membrane permeability and the degree of membrane lipid peroxidation in lemon flavedo following cold storage. The 10 μM MJ plus 2 mM SA treatment was most effective in enhancing chilling tolerance of lemon fruit, significantly reducing chilling-induced membrane permeability and membrane lipid peroxidation of lemon flavedo tissue. This treatment also increased total phenolics and PAL activity in such tissue while inhibiting POD activity, the latter possibly contributing to the delay of CI manifestation. PPO activity was found to be a poor biochemical marker of CI. Treatment with 10 μM MJ plus 2 mM SA resulted in an alteration of the phenolic metabolism, enhancing chilling tolerance, possibly through increased production of total phenolics and the activation of PAL and inhibition of POD.     

茉莉酸甲酯与真菌诱导物、水杨酸组合对红豆杉细胞中紫杉醇含量的影响

比较了茉莉酸甲酯与真菌诱导物、水杨酸组合对红豆杉细胞几个抗病相关指标（POD、CAT活力、H2O2含量）及紫杉醇含量的影响,3种信号分子的组合对POD、CAT、H2O2及紫杉醇含量的影响是不一致的,MJ单独添加,MJ与SA联合作用以及MJ与F5联合作用都可使POD活力增加,且12h后H2O2含量均升高,约在48h达到高峰,为对照的2倍左右,但72h后,MJ单独添加和MJ与SA联合作用组中H2O2含量变化不大,F5与MJ联合作用则使H2O2含量持续比对照高。MJ单独添加使CAT酶活在144h后才较对照低,F5、SA的加入都可使CAT酶活下降,SA的作用更显著。说明三者的诱导途径并不完全一样,以SA和MJ联合添加对紫杉醇合成的促进作用最大,含量达到细胞干重的0．04％。     

A comparative study of the effects of methyl jasmonate and abscisic acid on some rice physiological processes

The effects of methyl jasmonate (MJ) and abscisic acid (ABA) on some physiological processes of rice were compared. MJ exhibited ABA-like effects by promoting senescence of detached leaves, by inducing acid phosphatase activity of detached leaves, by inhibiting ethylene production and shoot growth of seedlings, as well as inhibiting callus formation from anthers. However, MJ and ABA had opposite effects on 1-aminocyclopropane-1-carboxylic acid-dependent ethylene production in detached leaves. The regeneration ability of anther-derived callus was inhibited by MJ but not by ABA. MJ but not ABA markedly induced peroxidase activity in senescing detached leaves. It is concluded that not all physiological processes of rice affected by MJ are similar to those by ABA.Abbreviations ABA abscisic acid - MJ methyl jasmonate - ACC 1-aminocyclopropane-l-carboxylic acid - Apase acid phosphatase     

Methyl jasmonate induces expression of a novel Brassica juncea chitinase with two chitin-binding domains

We have cloned a 1.3 kb Brassica juncea cDNA encoding BjCHI1, a novel acidic chitinase with two chitin-binding domains that shows 62% identity to Nicotiana tabacum Chia1 chitinase. BjCHI1 is structurally unlike Chia1 that has one chitin-binding domain, but resembles Chia5 chitinase UDA1, the precursor of Urtica dioica agglutinin; however there is only 36.9% identity between them. We propose that BjCHI1 should be classified under a new class, Chia7. The spacer and the hinge region of BjCHI1 are proline-rich, like that of Beta vulgaris Ch1, a Chia6 chitinase with half a chitin-binding domain. Northern blot analysis showed that the 1.3 kb BjCHI1 mRNA is induced by wounding and methyl jasmonate (MeJA) treatment but is unaffected by ethylene, salicylic acid (SA) or abscisic acid (ABA). This is the first report on MeJA induction of chitinase gene expression and further suggests that wound-related JA-mediated signal transduction is independent of that involving SA. Western blot analysis using polyclonal antibodies against BjCHI1 showed a cross-reacting band with an apparent molecular mass of 37 kDa in wounded tissues of B. juncea, revealing that, unlike UDA1, BjCHI1 is not cleaved post-translationally at the hinge. Expression of recombinant BjCHI1 in Escherichia coli BL21(DE3) inhibited its growth while crude extracts from E. coli JM109 expressing recombinant BjCHI1 showed chitinase activity. Results from polymerase chain reaction (PCR) suggest that genes encoding chitinases with single or double chitin-binding domains exist in B. juncea.