茉莉酸处理菜豆对美洲斑潜蝇抗性的影响

为明确外源茉莉酸(JA)处理菜豆对美洲斑潜蝇抗性的诱导作用,采用生物测定和生化分析方法,研究了4种浓度JA喷施菜豆幼苗后,菜豆对美洲斑潜蝇的抗性及菜豆叶片过氧化物酶(POD)、多酚氧化酶(PPO)和脂氧合酶(LOX)活性的变化.结果表明,JA处理可以提高菜豆对美洲斑潜蝇的抗性及菜豆叶片3种防御酶的活性,且其抗性和防御酶活性提高程度均与JA浓度有关.0.1、1 mmol/L JA可显著降低美洲斑潜蝇成虫对菜豆的取食和产卵选择性,使卵或幼虫发育历期延长、幼虫取食量降低、蛹重减轻,而0.001和0.01 mmol/L JA仅对幼虫发育历期有显著影响.0.1 mmol/L JA处理后,菜豆叶片POD、PPO和LOX活性均显著升高,分别较对照增加33％、39％和80％,而0.001 mmol/L JA对菜豆叶片防御酶诱导作用不明显.     

钙离子和茉莉酸灌根对菜豆叶片防御酶活性和西花蓟马取食偏好性的影响

为探明外源物质对菜豆植株防御酶活性和西花蓟马取食偏好性的影响。本试验分别采用CaCl₂和茉莉酸(JA)进行灌根,研究了西花蓟马取食前后菜豆叶片脂氧合酶(LOX)、丙二烯氧化物合酶(AOS)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和多酚氧化酶(PPO)活性的变化,并研究了西花蓟马对JA和CaCl₂处理后的菜豆植株的取食偏好性。结果表明：不论CaCl₂还是JA灌根均可诱导菜豆防御酶AOS、LOX、CAT和SOD活性的上升,其中对CAT活性影响最大,其活性分别上升至对照的2.83倍和3.57倍,但对POD和PPO活性没有影响。西花蓟马取食CaCl₂处理的菜豆植株,能诱导LOX、POD和PPO活性分别上升1.40、2.03倍和2.26倍,而SOD活性则被显著抑制。西花蓟马取食JA灌根的菜豆植株能明显诱导POD和PPO活性的升高,二者活性分别是未取食植株的1.67倍和1.45倍,但AOS、LOX、CAT和SOD活性被抑制。西花蓟马2龄若虫取食CaCl₂和JA...     

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。     

病菌侵染对番茄果实乙烯生成,ACC合成酶和脂氧合酶活性的影响

 本文以红熟期的番茄(Lycopersicon esculentum Mill.)果实为材料,主要研究病菌侵染与果实中乙烯生成,ACC合成酶和脂氧合酶(LOX)的关系,以及不同乙烯处理对感病果实ACC合成酶和脂氧合酶(LOX)活性的影响。结果表明:用葡萄孢菌(Botrytis cinerea)接种采后番茄果实在25℃下存放7d后,感病果实的乙烯释放量显著增加,ACC合成酶和脂氧合酶(LOX)活性也明显提高。在贮藏环境中增加乙烯吸收剂可明显地延缓葡萄孢菌的发病,而且ACC合成酶和LOX酶的活性也相对较低。由此证明病菌侵染与果实乙烯释放量,以及与ACC合成酶和LOX酶之间存在明显的正相关     

外源茉莉酸诱导对油菜防御酶活性和4种物质含量及植株生长的影响

油菜是我国重要的油料作物?近10年来油菜虫害呈重发态势, 而茉莉酸可以诱导植物产生抗虫性?本研究测定了外源茉莉酸处理对‘大黄’油菜幼苗中防御酶活性以及可溶性蛋白?可溶性糖?叶绿素?单宁含量及植株生长状况的影响?结果显示, 以100 μmol/L茉莉酸处理后, 油菜叶片中过氧化物酶(POD)?多酚氧化酶(PPO)?超氧化物歧化酶(SOD)和苯丙氨酸解氨酶(PAL)活性较对照均有提高?其中对PAL影响最大, 48 h时上升为对照的2.36倍; POD和PPO活性均在12 h后达到最高, 分别比对照增加了73.46%和49.21%; 对SOD活性在处理后24 h比对照增加了14.93%; 胰蛋白酶抑制剂(TI)活性在茉莉酸处理后48 h达到最大, 比对照提高了38.37%, 之后逐渐下降, 至120 h时与对照无显著差异; 胰凝乳蛋白酶抑制剂(CI)活性在茉莉酸诱导后一直增加, 120 h时是对照的1.78倍?可溶性糖和叶绿素含量在处理120 h均降到最低, 分别比对照降低了38.70%和17.83%?可溶性蛋白含量则先降低后升高, 在处理48 h后最低, 比对照降低47.98%?可溶性单宁在茉莉酸诱导后含量持续升高, 在120 h时上升为对照的2.03倍?油菜根长在茉莉酸处理后28 d和35 d显著长于对照; 株高和干重均与对照无显著差异?上述结果说明适当剂量的外源茉莉酸诱导可激活油菜的防御体系, 增强其抗虫性, 且不影响油菜的生长?     

稻瘟菌GP66激发子诱导的水稻膜脂过氧化及其保护酶活性变化

 以抗稻瘟病水稻近等基因系C101LAC及背景品系CO39为材料,研究稻瘟菌(Magnaporthe grisea)来源的GP66激发子诱导的水稻膜脂过氧化及保护酶活性变化.结果表明,激发子诱导非亲和性互作水稻超氧阴离子(O₂^·)积累和脂氧合酶(LOX)活性在早期明显高于亲和性互作水稻;O₂^·积累和LOX活性的升高进而导致了非亲和性互作水稻的膜脂过氧化,其相对电导率及丙二醛(MDA)含量出现的高峰期和强度也明显要早和高于亲和性互作水稻.超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性均趋于下降,不同亲和性互作水稻间的变化则不明显;非亲和性互作水稻过氧化物酶(POD)活性则在激发子诱导早期明显高于亲和性互作水稻,可能与其参与其它抗性有关.这些结果表明膜脂过氧化的发生是激发子诱导水稻抗性的主要生理机制之一.     

西花蓟马取食、机械损伤和外源物质诱导对番茄植株次生物质及西花蓟马解毒酶的影响

为阐明寄主植物番茄受害虫西花蓟马Frankliniella occidentalis取食、机械损伤及外源物质茉莉酸和水杨酸甲酯诱导后次生物质含量的变化,以及害虫如何通过调整体内解毒酶活性适应植物的防御反应,采用生化分析法测定了各诱导处理下次生物质黄酮、总酚和单宁含量及西花蓟马体内解毒酶多功能氧化酶(MFO)、乙酰胆碱酯酶(AchE)、谷胱甘肽S-转移酶(GSTs)和羧酸酯酶(CarE)活性的变化。结果表明:番茄叶片在各诱导处理下黄酮含量在36 h和48 h时均显著高于对照,相应时间段茉莉酸处理与水杨酸甲酯处理的黄酮含量升高最显著,分别达32.07 mg/g和31.76 mg/g;各诱导处理后24 h和36 h时,单宁和总酚含量均有不同程度下降,但总酚含量在48 h时显著升高,其中虫害处理增加最显著,达34.51 mg/g。取食各种诱导处理番茄植株6 h时,西花蓟马体内MFO活性均升高,AchE活性均受到抑制;取食除机械损伤外的其它诱导处理叶片6 h后,西花蓟马体内GSTs活性均被抑制,CarE活性均显著上升,其中取食水杨酸甲酯处理叶片的西花蓟马体内GSTs活性下降幅度最大,而CarE活性升高最显著,分别为3 882.35 U/mg和106.33 U/mg。表明各诱导处理不仅可以使番茄次生物质含量发生变化,诱导植株产生防御反应,也会使西花蓟马改变解毒酶的活性以适应寄主植物的诱导抗性,即寄主植物和害虫通过防御与反防御相互适应。     

活性氧及膜脂过氧化与棉花对枯萎病抗性的关系

 萎病菌侵染后,抗病品种棉苗及经氟乐灵诱发处理产生对枯萎病诱导抗性的棉苗茎与根组织中,膜脂过氧化产物丙二醛(MDA)含量上升,膜系统中不饱和脂肪酸含量下降,表明有膜脂过氧化的发生,超氧阴离子(O₂^·)的产生速率、H₂O₂的积累水平及脂氧合酶(LOX)活性也明显增加,但超氧化物歧化酶(SOD)及过氧化氢酶(CAT)活性无显著差异。与此相反,感病品种棉苗受侵后MDA含量、O₂^·产生速率、H₂O₂的积累及LOX酶活性增加幅度较小,SOD及CAT酶活性则明显上升,膜系统中不饱和脂肪酸含量仅有小幅度下降。氟乐灵播前土壤处理可诱发棉苗对枯萎病的诱导抗性,同时也增加了LOX酶活性及活性氧(O₂^·、H₂O₂)的积累。这些结果说明,枯萎病菌侵染后棉苗体内活性氧的积累、LOX酶活性的上升以及由此引起的膜脂过氧化,可能在棉苗对枯萎病的抗性中起作用。     

亲和病原菌诱导黄瓜组织结构抗病性机制

炭疽病菌预先接种黄瓜可以诱导其产生对褐斑病的抗性.经炭疽病菌(1.0×106个孢子/mL)诱导48h后,黄瓜对褐斑病的抗性最大可达97.83%.在同种马铃薯葡萄糖液体培养基中培养,这两种病原菌的竞争力差异显著,黄瓜炭疽病菌能够获得更多的营养物质,生长旺盛,而褐斑病菌的生长则受到严重抑制.经苯胺兰染色发现,炭疽病菌诱导后黄瓜叶片中胼胝质的积累量显著增加.此外,黄瓜炭疽病菌与褐斑病菌的侵染方式存在一定的差异,前者可以通过气孔或直接穿透细胞壁侵入寄主.而后者只能通过直接穿透细胞壁侵入寄主.     

茉莉酸诱导水稻幼苗对稻瘟病抗性作用研究

 外源茉莉酸处理可以显著减轻水稻幼苗稻瘟病的发生。JA诱导稻苗产生抗病性的有效浓度是0.1~0.001mmol/L,喷雾处理后2d接种稻瘟病菌获得最佳的抗病效果。0.1mmol/L JA喷雾处理后2d接种稻瘟病菌,水稻幼苗的诱抗效果都超过了55%。JA处理的诱导抗性可以维持15d左右。用0.1mmol/L JA二次强化处理水稻幼苗可以增强诱导抗病性,延长抗性的持续期。JA诱导水稻幼苗抗性机制的结果表明:0.1mmol/L JA处理可以诱导水稻体内苯丙氨酸解氨酶、过氧化物酶活性和木质素升高。     

茄子棒孢叶斑病病原菌鉴定及致病性研究

 本研究对茄子棒孢叶斑病的症状进行系统的描述,采用致病性试验、形态学观察及分子生物学的方法对茄子棒孢叶斑病的病原菌进行鉴定。致病性试验证实病原菌对茄子的致病力显著高于黄瓜。显微观察发现同一病原菌在茄子上形成的孢子以圆柱形为主,孢子体较窄;而在黄瓜上形成的孢子具有圆柱形和倒棍棒形两种形态,且较宽。对病原菌rDNA ITS区进行PCR扩增和序列测定。综合形态特征、致病力和分子序列分析结果,确定茄子棒孢叶斑病病原菌为Corynespora cassiicola。     

唑菌酯对8种蔬菜病原菌的生物活性

通过盆栽试验测定了唑菌酯对8种蔬菜病原菌的生物活性。结果表明,其对黄瓜灰霉病菌Botrytis cinerea、黄瓜霜霉病菌Pseudoperonospora cubensis、黄瓜炭疽病菌Colletotrichum orbiculare、黄瓜褐斑病菌Corynespora cassiicola和黄瓜黑星病菌Cladosporium cucumerinum具有较高活性,EC50值分别为 9.457、12.69、11.09、6.453和4.106 mg/L。 其中,在 250 mg/L 浓度下唑菌酯处理的防病效果与对照药剂嘧菌酯相当,防效大于75%。田间药效试验结果表明,20% 唑菌酯悬浮剂有效成分 80 mg/L 对黄瓜霜霉病的防效达 82.78%。     

Molecular Characterization and Diagnosis of QoI Resistance in Cucumber and Eggplant Fungal Pathogens

ABSTRACT The molecular mechanism of QoI fungicide resistance was studied using isolates of cucumber Corynespora leaf spot fungus (Corynespora cassiicola) and the eggplant leaf mold (Mycovellosiella nattrassii). In both pathogens, a mutation at position 143 from glycine to alanine (G143A) was detected in the cytochrome b gene that encodes for the fungicide-targeted protein. Moreover, the nucleotide sequence at amino acid position 143 was converted from GGT or GGA in sensitive (wild-type) to GCT or GCA in resistant (mutant-type) isolates. The methods of polymerase chain reaction restriction fragment length polymorphism commonly used for QoI resistance monitoring were employed successfully, leading to the amplified gene fragment from resistant isolates being cut with the restriction enzyme ItaI. However, heteroplasmy (the coexistence of wild-type and mutated alleles) was found when the resistant isolates of C. cassiicola, M. nattrassii, and Colletotrichum gloeosporioides (strawberry anthracnose fungus) were subcultured in the presence or absence of QoI fungicides. QoI resistance of cucumber powdery and downy mildew isolates persisted for a few years following the removal of the selection pressure imposed by the fungicide under both laboratory and commercial greenhouse conditions. The proportion of mutated sequences in cytochrome b gene decreased over time in the pathogen population. The protective efficacy of the full dose of azoxystrobin decreased when the populations of powdery and downy mildews contained resistant isolates at 10%. Using FMBIO, a fluorescence bio-imaging analyzer, the mutant allele from the QoI-resistant isolates could be detected at the level of 1%, whereas the detection sensitivity of ethidium-bromide-stained gels was approximately 10 times lower.     

巴西橡胶树品系对棒孢霉落叶病的抗病性鉴定

采用巴西橡胶树棒孢霉落叶病病原菌的分生孢子接种和其毒素接种分别测定了国内天然橡胶主产区9个主栽品系的抗病性,结果表明过滤灭菌毒素划伤接种橡胶离体小叶片可以产生与分生孢子接种相似的症状,而不划伤接种则不产生病害症状;121℃、20 min湿热灭菌毒素接种无论划伤与否均不产生病害症状;分生孢子和病原菌毒素两种接种方法所测橡胶品系的抗病性之间有很好的一致性,说明毒素接种可以用来代替病原菌接种测定橡胶品系的抗病性。抗病性测定结果显示,供试9个巴西橡胶树品系中,PB86、热研88-13、南华1、PR107、热研7-33-97对病原菌表现出高抗,而RRIM600、南强1-97、热研44-9则表现高感,GT1则表现中感。     

黄瓜褐斑病（Corynespora cassiicola）在广东首次报道

2011年5月和8月,在广东省高要市和增城市黄瓜主产区发现黄瓜褐斑病,致病性测定、形态学观察和rD-NA-ITS序列分析结果表明,引起广东黄瓜褐斑病的病原菌为多主棒孢霉(Corynespora cassiicola)。本文是多主棒孢霉在广东引起黄瓜褐斑病的首次报道。     

水稻近等基因系与白叶枯病菌互作的生理指标研究

用抗水稻白叶枯病的近等基因在ＣＢＢ３（Ｘａ－３）、ＣＢＢ４（Ｘａ－４）、ＣＢＢ１２（Ｘａ－１２）和感病轮回亲本沈农１０３３一两个致病力不同的白叶枯病菌株７５－１、７６－２５组成非亲和性和亲和性反应的组合。以无菌水模拟接种为对照,成株期剪叶接种后分别在不同时间取样测定叶片的苯丙氨酸解氨酶（ＰＡＬ）、过氧化物酶（ＰＯ）和超氧化物歧化酶（ＳＯＤ）活性。ＰＡＬ活性在处理后４８ｈ达到高峰,且接种病菌后的酶活     

Biological control mechanisms of D-pinitol against powdery mildew in cucumber

D-pinitol is an effective agent for controlling powdery mildew (Podosphaera xanthii) in cucumber. In this study, we determined the mechanisms of D-pinitol in controlling powdery mildew in cucumber plants. We compared P. xanthii development on cucumber leaf surface treated with D-pinitol or water (2 mg ml⁻¹) at different time points after inoculation. The germinating conidia, hyphae, and conidiophores of the pathogen were severely damaged by D-pinitol at any time of application tested. The highest level of suppression of fungal development was obtained at 3 days after inoculation. The contents of chlorophyll, total phenolics, flavonoid, and gallic acid and its derivatives (GAD); the activities of phenylalanine ammonialyase (PAL), polyphenoloxidase (PPO), peroxidase (POX), and superoxide dismutase (SOD); and the expression of the genes encoding for PR-1, peroxidase (POX), lipoxygenase (LOX1), chitinase (Chit1) were higher in the cucumber leaves treated with D-pinitol and inoculated than in the leaves either treated with D-pinitol or inoculated with the pathogen. These results suggest that D-pinitol triggers several plant defense responses in cucumber leading to pathogen suppression and resistance to powdery mildew.     

多主棒孢和棒孢叶斑病的研究进展

多主棒孢Corynespora cassiicola是一种重要的植物病原真菌,寄主范围广泛,能够侵染530余种植物。由多主棒孢引起的棒孢叶斑病在橡胶、蔬菜等作物上流行性暴发,对农作物产业发展构成严重威胁。该文简述了多主棒孢的分类地位和形态特征,对该病原菌的遗传多样性和毒素蛋白结构等方面的研究进行了较为全面的概括。另外,总结了近年来国内外在棒孢叶斑病诊断和防治研究中取得的成果和存在的问题,并提出了我国多主棒孢病原学及病害防治方面的研究方向。     

Role of methyl jasmonate in the expression of mycorrhizal induced resistance against Fusarium oxysporum in tomato plants

Arbuscular mycorrhiza (AM) colonization led to a decrease in the severity of fusarium wilt disease caused by Fusarium oxysporum f. sp. lycopersici in tomato plants. The involvement of two plant defense hormones, namely methyl jasmonate (MeJA) and salicylic acid (SA), in the expression of mycorrhiza induced resistance (MIR) against this vascular pathogen was studied in the AM colonized and non-colonized (controls) plants. Activity of lipoxygenase (LOX), which plays a role in jasmonic acid (JA) biosynthesis, as well as levels of methyl jasmonate (MeJA) increased in AM colonized plants as compared to controls, but did not show any further changes in response to F. oxysporum inoculation. On the other hand, activity of phenylalanine ammonia lyase (PAL), which is an enzyme from salicylic acid (SA) biosynthetic pathway, as well as SA levels, increased in both controls and AM colonized plants in response to application of F. oxysporum spores. Hence the JA and not the SA signalling pathway appeared to play a role in the expression of MIR against this vascular pathogen. The resistance observed in AM colonized plants was completely compromised when plants were treated with the JA biosynthesis inhibitor salicylhydroxamic acid (SHAM). This confirmed that the AM-induced increase in JA levels was involved in the expression of resistance toward F. oxysporum. The SA response gene pathogenesis-related 1 (PR1) showed an increased expression in response to F. oxysporum infection in SHAM treated AM colonized plants as compared to plants that were not treated with this JA inhibitor. This suggested the possibility that JA inhibited SA responses, at least in the roots. AM colonization therefore appeared to prime plants for improved tolerance against the vascular pathogen F. oxysporum, which was mediated through the JA signalling pathway.     

哈茨木霉SH2303防治玉米小斑病的初步研究

哈茨木霉SH2303是本实验室分离获得的1株具有生防效果的菌株,该菌株能够较好的防治玉米小斑病。通过离体叶片试验确定哈茨木霉SH2303诱导玉米抗小斑病的持效期达15 d。盆栽及大田试验表明,防治玉米小斑病防效分别达到78.1%和56.3%。盆栽试验表明,哈茨木霉 SH2303处理的叶片在挑战接种小斑病菌后第36 h,玉米体内防御反应酶系PAL和SOD活性达到峰值。同时,防御基因Pal和Sod的表达水平也明显上升。综合分析表明,哈茨木霉SH2303的诱导抗性作用是防治玉米小斑病的重要机制之一。