Activity against plant pathogenic fungi of phomalactone isolated from Nigrospora sphaerica

Phomalactone, 5,6‐dihydro‐5‐hydroxy‐6‐prop‐2‐enyl‐2H‐pyran‐2‐one, produced by the fungus Nigrospora sphaerica, was tested in vitro against nine plant pathogenic fungi, and specifically inhibited the mycelial growth of Phytophthora infestans, with an MIC value of 2.5 mg litre^?1. Its inhibitory activities against sporangium and zoospore germination of P infestans were similar to those against Phytophthora capsici. In vivo, at 100 and 500 mg litre^?1, it reduced the development of tomato late blight caused by P infestans. © 2001 Society of Chemical Industry     

Note:In vitro antagonism of actinomycetes isolated from fungus-growing ants against plant pathogenic fungi

Fungus-growing ants have been found recently to be symbiotic with actinomycetes living on the ant’s cuticle; these bacteria are inhibitory to soil fungi that are detrimental to the ants’ fungus gardens. In order to investigate whether actinomycetes found on the cuticle of attine ants also had inhibitory properties against plant pathogenic fungi, we isolated 32 strains of actinomycetes from fungus-growing ants (Atta, Trachymyrmex, andCyphomyrmex), from the Mexican states of Coahuila, Nuevo León and Tamaulipas. Of the actinomycetes tested against selected plant pathogenic fungi (Alternaria solani, Aspergillus flavus, Colletotrichum lindemuthianum, Rhizoctonia solani, Sclerotium sp.) on Czapek-Dox agar medium, 13 isolates inhibited at least one of the fungi.C. lindemuthianum was inhibited by 11 actinomycetes, andRhizoctonia by three. An actinomycete strain isolated fromCyphomyrmex rimosus inhibited all five fungi tested. http://www.phytoparasitica.org posting July 30, 2008.     

嗜线虫致病杆菌SN313的次生代谢产物及其抑制植物病原真菌活性研究

通过化学与生物活性筛选从土壤中分离得到一株菌株,利用16S rDNA方法将其鉴定为嗜线虫致病杆菌Xenorhabdus nematophila并命名为SN313。采用微生物发酵、液相萃取、柱层析及半制备高效液相色谱等技术,对SN313的发酵液进行分离纯化,得到3个化合物。利用质谱和核磁共振等波谱技术并依据文献数据确定了这3个化合物分别是N-(2-羟基苯基乙酰) 色胺 ( 1 )、吩嗪-1-羧酸 ( 2 ) 和环(脯氨酸-色氨酸) ( 3 ),其中化合物 1 是一个新的β-吲哚基乙胺类衍生物。通过微量稀释法测定了3个化合物对4种植物病原真菌的抑制活性。结果表明:化合物 1 对辣椒疫霉Phytophthoa capsici和番茄灰霉病菌Botrytis cinerea具有明显的抑制作用 (IC₅₀值分别为11.20 μg/mL和28.94 μg/mL);化合物 2 对番茄灰霉病菌、辣椒疫霉、水稻纹枯病菌Thanatephorus cucumeris和小麦根腐病菌Bipolaris sorokiniana有明显的抑制作用 (IC₅₀ < 40 μg/mL);化合物 3 对番茄灰霉病菌具有较好的抑制效果 (IC₅₀ = 41.58 μg/mL)。从土壤微生物中获取化合物 2 ,为生物农药申嗪霉素有效成分的天然获取提供了一种新的途径。     

雷帕霉素对4种植物病原真菌的抑菌活性

采用菌丝生长速率法,测定了雷帕霉素对番茄灰霉病菌、油菜菌核病菌、水稻纹枯病菌和棉花枯萎病菌的抑菌活性,比较了嘧菌酯、丙烷脒及雷帕霉素对番茄灰霉病菌的抑菌效果,并通过电子显微镜观察了雷帕霉素对番茄灰霉病菌菌丝生长的影响。结果表明:雷帕霉素对供试4种植物病原真菌菌丝均表现出了极强的抑制活性,其中对油菜菌核病菌的抑制作用最强,EC50值为2.23×10-4μg/mL,对番茄灰霉病菌、水稻纹枯病菌和棉花枯萎病菌的EC50值分别为1.32×10-3、4.05×10-3及3.82×10-3μg/mL;雷帕霉素对番茄灰霉病菌菌丝的抑制活性显著高于嘧菌酯(EC50值为3.24μg/mL)和丙烷脒(EC50值为3.81μg/mL)。电镜观察发现,经雷帕霉素处理后,番茄灰霉病菌菌丝表现出提前衰老等症状。研究结果可为深入探讨雷帕霉素对植物病原真菌的作用机制奠定基础。     

羌活提取物对8种植物病原真菌抑制活性研究初报

采用菌丝生长速率法研究了羌活(Notopterygium incisum Ting ex H.Chang)甲醇粗提物及其不同极性溶剂萃取物对8种植物病原真菌的抑制活性。结果表明,当含药培养基中羌活甲醇粗提物的浓度为1.0 mg/m L时,其对苹果腐烂病病菌与葡萄白腐病病菌的抑制活性较好,抑制率均大于75%。进一步采用系统溶剂法对羌活甲醇粗提物进行萃取,发现乙酸乙酯萃取物抑菌活性较好,表明羌活抑菌活性成分主要为中低极性化合物。当含药培养基中乙酸乙酯萃取物浓度为1.0 mg/m L时,其对苹果腐烂病病菌与葡萄白腐病病菌的抑制率均大于90%,EC50分别为0.22 mg/m L与0.26 mg/m L。     

Dehydro-alpha-lapachone isolated from Catalpa ovata stems: activity against plant pathogenic fungi

The methanol extract of stems of Catalpa ovata G Don exhibits potent in vivo antifungal activity against Magnaporthe grisea (Hebert) Barr (rice blast) on rice plants, Botrytis cinerea Pers ex Fr (tomato grey mould) and Phytophthora infestans (Mont) de Bary (tomato late blight) on tomato plants, Puccinia recondita Rob ex Desm (wheat leaf rust) on wheat plants and Blumeria graminis (DC) Speer f. sp. hordei Marchal (barley powdery mildew) on barley plants. An antifungal substance was isolated and identified as dehydro-alpha-lapachone from mass and nuclear magnetic resonance spectral data. It completely inhibited the mycelial growth of B. cinerea, Colletotrichum acutatum Simmonds, Colletotrichum gloeosporioides Simmonds, M. grisea and Pythium ultimum Trow over a range of 0.4-33.3 mg litre(-1). It also controlled the development of rice blast, tomato late blight, wheat leaf rust, barley powdery mildew and red pepper anthracnose (Colletotrichum coccodes (Wallr) S Hughes). The chemical was particularly effective in suppressing red pepper anthracnose by 95% at a concentration of 125 mg litre(-1).     

黄粉虫抗菌肽抑制植物病原真菌的适宜诱导处理

对饥饿后黄粉虫幼虫通过饲细菌、针刺饲真菌或放线菌法产生诱导免疫反应;研磨、冷冻离心法获得抗菌肽提取物.采用抑菌圈法测定其对24种植物病原真菌抑菌活性,统计分析抑菌活性处于前3名处理的频次.结果表明,初步得到了抑制植物病原真菌的黄粉虫抗菌肽适宜诱导处理.诱导处理方法对开发包括黄粉虫在内的昆虫抗菌肽是非常重要的.     

茜草等25种中药材对5种植物病原真菌的抑制活性

以苹果腐烂病菌、苹果轮纹病菌、棉花枯萎病菌、柑橘炭疽病菌与白菜黑斑病菌为供试菌,采用生长速率法测定25种中药材甲醇粗提物的抑菌活性。结果表明,在浓度为5.0mg/mL时,大部分中药材的甲醇粗提物对至少一种植物病原真菌都表现出不同程度的抑制活性,其中知母、青蒿、细辛与白鲜皮对3种供试植物病原菌的抑制率大于75%,而茜草与姜黄对4种供试植物病原菌的抑制率均在80%以上,具有广泛的抑菌谱。进一步采用系统溶剂法得到的茜草不同溶剂萃取物中,水饱和正丁醇相抑菌活性明显优于石油醚及乙酸乙酯相,表明茜草抑菌活性成分主要为中等及大极性化合物。     

中药植物金线吊乌龟对植物病原真菌的抗菌活性

采用菌丝生长速率法测定了中药植物金线吊乌龟块根甲醇提取物对5种植物病原真菌的抗菌活性,结果表明:金线吊乌龟块根提取物对梨锈病菌、稻瘟病菌、水稻纹枯病菌和玉米炭疽病菌有很高的抑制活性,质量浓度为10g/L时,抑菌率分别为97.74%、100.00%、94.51%和84.40%;有效中浓度(EC50)分别为0.5879、0.3122、0.2807g/L和0.8353g/L。对柿角斑病菌的活性较低,在10g/L质量浓度下,抑菌率只有67.59%,EC50为1.3491g/L。金线吊乌龟块根提取物对甘蔗凤梨病菌孢子、柑橘疮痂病菌孢子和梨锈病菌孢子的萌发具有明显的抑制活性,质量浓度为10g/L时,抑制率分别为91.80%、97.00%和100.00%;对西瓜枯萎病菌孢子萌发的抑制效果比较差,抑制率仅为20.63%。按生物碱分离程序对金线吊乌龟块根提取物进行初步分离,结合活性跟踪,发现氯仿层生物碱是金线吊乌龟的主要抗菌活性成分。     

Isolation and antifungal activity of lignans from Myristica fragrans against various plant pathogenic fungi

BACKGROUND: In a search for plant extracts with potent in vivo antifungal activity against various plant diseases, we found that treatment with a methanol extract of Myristica fragrans Houttyn (nutmeg) seeds reduced the development of various plant diseases. The objectives of the present study were to isolate and determine antifungal substances from My. fragrans and to evaluate their antifungal activities. RESULTS: Three antifungal lignans were isolated from the methanol extract of My. fragrans seeds and identified as erythro-austrobailignan-6 (EA6), meso-dihydroguaiaretic acid (MDA) and nectandrin-B (NB). In vitro antimicrobial activity of the three lignans varied according to compound and target species. Alternaria alternata, Colletotrichum coccodes, C. gloeosporioides, Magnaporthe grisea, Agrobacterium tumefaciens, Acidovorax konjaci and Burkholderia glumae were relatively sensitive to the three lignans. In vivo, all three compounds effectively suppressed the development of rice blast and wheat leaf rust. In addition, EA6 and NB were highly active against the development of barley powdery mildew and tomato late blight, respectively. Both MDA and NB also moderately inhibited the development of rice sheath blight. CONCLUSION: This is the first study to demonstrate the in vitro and in vivo antifungal activities of the three lignans from My. fragrans against plant pathogenic fungi.     

伞形花内酯对植物病原真菌的抑制作用

[目的]研究伞形花内酯对桃褐腐病菌、棉花红腐病菌、草莓灰霉病菌、辣椒炭疽病菌的抑制活性,探究其对前两种病菌的抑菌机理。[方法]采用生长速率法测定伞形花内酯对4种植物病原真菌的抑制活性;采用二倍稀释法测定最小抑菌浓度和孢子萌发率;采用扫描电镜和透射电镜观察伞形花内酯对前两种病原菌超微结构的破坏。[结果]伞形花内酯对前两种植物病原菌具有较强的抑制作用,它们的MIC为250μg/mL和500μg/mL。后两种植物病原菌的MIC分别为1 000、2 000μg/mL。在伞形花内酯的作用下,菌丝外观出现变形、内容物外溢。菌丝内部出现空腔,细胞器降解,胞质凝集、出现流失,细胞结构遭到破坏,致使细胞死亡。[结论]伞形花内酯具有较强的抗菌活性,具有作为植物源杀菌剂的开发潜力。     

八株番茄内生细菌对12种病原真菌拮抗活性的测定

正内生细菌普遍存在于高等植物中,已发现的种类超过80个属(Lodewyckx et al.,2002),可通过产生抗生素、营养竞争和生态位排斥、触发植物的诱导性系统抗性等机制有效减轻或控制植物病害,从而减轻化学杀菌剂使用带来的残留、环境污染、病原菌抗药性及生态平衡破坏等问题。番茄在全世界种植历史悠久,在与病原菌长期的协同进化过程中,必然     

竹红菌甲素对18种植物病原菌的抑制作用

Inhibition of Hypocrellin A (HA) against 18 pathogenic fungi by mycelium growth rate in light and dark conditions was evaluated. The results showed that 50 mg·L^-1 HA exhibited antifungal activities against all of 18 pathogenic fungi under luminous intensity of 12 000 Lx. The inhibition rates of HA to Lecanosticta acicola, Fusarium graminearum, Valsa mali and Botryosphaeria dothidea were all higher than 90%. The EC₅₀ of HA to Botryosphaeria dothidea and Lecanosticta acicola was 0.60 mg·L^-1 and 0.77 mg·L^-1 respectively. However, HA showed weak and even no antifungal activity in dark condition. The study suggested that the potential of HA could be as a new kind of photoactivated biopesticide.     

植物病原真菌对杀菌剂抗性的研究进展

科学施用杀菌剂是植物病害综合治理的重要措施之一, 然而由于杀菌剂的长期使用, 病菌抗药性问题逐渐加重, 严重影响药剂的防治效果和使用寿命。近年来, 随着分子生物学技术的快速发展, 人们对杀菌剂抗性机制有了更深入的理解, 并开发出了病菌抗药基因型快速检测的方法。本文总结了植物病原真菌对苯并咪唑类杀菌剂(BZD)、肌球蛋白合成抑制剂、甾醇脱甲基抑制剂(DMI)、QoI类抑制剂、琥珀酸脱氢酶抑制剂（SDHI）和二甲酰亚胺类杀菌剂(DC)的抗药性现状与抗性机制。在此基础上, 介绍了聚合酶链反应(PCR)、限制性片段长度多态性(RFLP)、等位基因特异性PCR和环介导等温扩增(LAMP)技术在杀菌剂抗性快速检测方面的研究进展。此外, 对抗药性治理对策进行了讨论和展望。     

Testing for heterothallism and mating-type in plant pathogenic fungi

When attempts are made to cross two strains of a heterothallic obligately parasitic fungus, the absence of any evidence of sexual processes can be caused either by mating-type incompatibility or failure to achieve simultaneous infection by both strains. A simple statistical test is described to discriminate between these alternatives when the number of replicates of each cross is small or not all plants are successfully infected.     

黄皮酰胺类生物碱的提取及对7种水果病原真菌的抑菌活性

利用菌丝生长速率法测定黄皮果核甲醇提取物对芒果炭疽病菌(Colletotrichum gloeosporioides Penz)等7种水果病原真菌的抑制活性,结果表明该提取物10 mg/mL浓度下对芒果炭疽病菌和香蕉枯萎病菌（Fusarium oxysporum f.sp. cubense）菌丝生长抑制率分别达到87.36%和84.55%。从黄皮果核甲醇提取物中分离得到生物总碱,测定其对上述两种真菌的EC50值分别为0.78 mg/mL和0.81 mg/mL。生物总碱进一步分离纯化得到新肉桂酰胺类化合物lansiumamide B, 在0.08 mg/mL浓度下,对芒果炭疽病菌和香蕉枯萎病菌的菌丝生长抑制率分别为 83.33%和60.78%。