两种季铵盐阳离子表面活性剂对番茄灰霉病菌的生物活性

为探讨季铵盐阳离子表面活性剂在番茄灰霉病防治中的应用潜力,室内采用菌丝生长速率法测定了五种阳离子表面活性剂对番茄灰霉病菌Botrytis cinerea的毒力作用,筛选出具有较高抑菌活性的1227(十二烷基二甲基苄基氯化铵)和C8-10(双八、十烷基季铵盐),并研究了其对该菌菌丝干重、分生孢子萌发、产孢量、菌核形成及细胞膜透性的影响。结果表明,五种阳离子表面活性剂中1227和C8-10对病原菌菌丝生长有较强的抑制作用,EC50值分别为8.39和5.82μg/mL,其毒力高于常规对照药剂腐霉利水悬浮剂,与嘧霉胺水悬浮剂、乙霉威水悬浮剂相当。两者对菌丝干重、孢子萌发均有较强的抑制作用,20μg/mL时抑制率接近或达到100%;对菌核数、菌核形态及分布有一定影响;40μg/mLC8-10对该菌产孢量的抑制率可达90%以上;1227和C8-10的浓度大于20μg/mL时均能明显影响病原菌细胞膜的通透性。     

7种植物精油对番茄灰霉病的抑制效果

以番茄灰霉病菌为供试对象,系统测试了香茅油、柠檬草油、樟油、黄樟油、天然冬青油、山苍子油、肉桂油等7种植物精油的抑菌效果。结果表明:7种精油中,樟油和肉桂油对番茄灰霉病的抑制效果较好。离体活性测试中,樟油和肉桂油对番茄灰霉病菌菌丝生长抑制作用的EC50分别为126.6205mg/L和128.1587mg/L,对孢子萌发的EC₅₀分别为181.8763mg/L和228.5453mg/L;活体组织法测试表明,2种精油对番茄灰霉病具有较好的保护效果,在500mg/L浓度下,黄瓜子叶法防效均达100%,果实针刺法防效分别为52.42%和50.48%;盆栽试验表明两者在2000mg/L时,对番茄灰霉病的防效分别为59.65%和61.40%。     

Biological control ofBotrytis cinerea in residues and flowers of Rose (Rosa hybrida)

Microbial isolates from living petals, petal residues and leaf residues of rose, and from laboratory collections, were evaluated for control ofBotrytis cinerea in rose. In leaf residues artificially infested withB. cinerea, isolates of the filamentous fungiGliocladium roseum, FR136 (unidentified) andTrichoderma inhamatum reduced sporulation of the pathogen by >90%, other filamentous fungi were 25–90% effective, and those of yeasts and bacteria were <50% effective. In artificially inoculated petal residues, no microbe reduced sporulation ofB. cinerea by >75%, but isolates ofCladosporium oxysporum and four yeasts were 51–75% effective, and three filamentous fungi, eight yeasts andBacillus subtilis isolates were 26–50% effective. Isolates ofT. inhamatum, C. oxysporum andG. roseum performed best againstB. cinerea among isolates evaluated in leaf residues naturally infested with the pathogen and indigenous microorganisms. Totals of ten isolates of filamentous fungi (includingC. oxysporum andC. cladosporioides), two of yeasts and five ofBacillus subtilis completely prevented lesion production byB. cinerea in detached petals, and a further six isolates of filamentous fungi (includingG. roseum) and six yeasts were 90–99% effective. Isolates ofC. oxysporum, C. cladosporioides andB. subtilis, the most effective microorganisms againstB. cinerea in flower buds, reduced number of lesions in the range of 42–65% compared with 59–89% for à standard fungicide (vinclozolin). It is suggested that application of leading antagonists Jo living rose leaves and flowers should optimize control of inoculum production byB. cinerea when the tissues die. Optimal biocontrol of lesion production in flower buds requires a better understanding of the microenvironment of petals.     

顶果木灰霉病病原鉴定

【目的】对顶果木灰霉病病原菌进行鉴定,以明确其分类地位,为顶果木灰霉病的防控提供参考依据。【方法】从广西南宁市良凤江国家森林公园苗圃基地采集顶果木灰霉病病害标本,对病害进行症状描述、组织分离和致病性测定,观察致病菌的形态学特征并进行r DNA-ITS序列分析。【结果】分离获得顶果木灰霉病致病菌代表菌株DGM5-6。DGM5-6菌株在PDA上长势良好,毛绒状菌落初期呈淡黄白色,后期逐渐变为灰白色;气生菌丝呈放射状生长,开始为白色,生长后期为灰色;病菌分生孢子梗单生,灰色至褐色,分枝,顶端膨大成球形,其上有多个小梗,梗上聚生卵形、圆形或椭圆形的分生孢子;分生孢子呈浅灰色至无色,单胞,大小为10.0-12.5μm×7.5-10.0μm。DGM5-6菌株ITS基因扩增片段长度为535 bp,其r DNA-ITS序列与Gen Bank中灰葡萄孢（Botrytis cinerea Pers.ex Fr）序列的同源性达99%。【结论】引起广西顶果木灰霉病的病原为灰葡萄孢（Botrytis cinerea Pers.ex Fr）,该病原菌寄主范围广,应结合苗圃清园、圃地治理、合理密植、生物防治和化学防治等进行防控。     

gacS基因在荧光假单胞菌FD6防治番茄灰霉病中的功能分析

 荧光假单胞菌（Pseudomonas fluorescens）FD6可产生多种抗菌物质,对多种植物病原真菌生长都有抑制作用。将FD6菌株感应激酶gacS基因部分保守区片段克隆到自杀载体中得到质粒pBS-S,将该质粒电击转化到FD6菌株中,利用同源重组构建了gacS基因插入突变体。经测定该突变体不产生抗生素硝吡咯菌素、2,4–二乙酰基间苯三酚、藤黄绿脓菌素、蛋白酶和氢氰酸,与野生型菌株相比形成生物膜和嗜铁素能力显著降低,并且丧失了对番茄灰霉病防病能力。gacS基因互补试验结果表明,gacS基因表达可恢复产生次生抗菌物质的能力,且对番茄灰霉病的防治效果与野生型菌株接近。由此证明,gacS基因是影响拮抗细菌FD6抗生素产生和对病害抑制能力的重要调控因子。     

Potassium silicate and chitosan application for gray mold management in strawberry during storage

The objective of this study was to investigate the effect of silicon and chitosan as alternative controls for postharvest rot of strawberries (gray mold) caused by Botrytis cinerea. Chitosan and potassium silicate applications were performed at the preharvest stage using the following treatments: chitosan once a week; potassium silicate once a week; potassium silicate once a week + chitosan once a week; and without application. An additional variable was introduced at postharvest, with one-half of the total fruit harvested from each plot dipped in chitosan and the other half not dipped in chitosan. Potassium silicate alone was not effective for rot control. Fruits from plants that received the chitosan application showed 64% less area under the rot progress curve (AURPC) than fruits from plants that were not treated with chitosan. Harvested fruits that were chitosan dipped showed 48% less AURPC than fruits that were not treated at postharvest. Chitosan application in the field and at postharvest is a promising strategy for the management of postharvest strawberry rot.     

Bis(2,3-dibromo-4,5-dihydroxybenzyl) Ether,a Marine Algae Derived Bromophenol,Inhibits the Growth of Botrytis cinerea and Interacts with DNA Molecules

Bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (BDDE) is a bromophenol isolated from marine algae. Previous reports have shown that BDDE possesses cytotoxic and antibacterial activity. In the present study, we demonstrate that BDDE displays broad-spectrum antifungal activities, especially on Botrytis cinerea. BDDE inhibits the growth of B. cinerea cultured on a solid medium of potato dextrose agar (PDA) as well as on the potato dextrose broth (PDB) medium. Moreover, BDDE decreases the incidence of fruit decay and severity of strawberries infected with B. cinerea. Further studies have revealed that BDDE decreases the germination rate and inhibits the mycelial growth of B. cinerea. The inhibition mechanisms are related to the disruption of the cell membrane integrity in B. cinerea spores and newly formed germ tubes. This study also suggests that BDDE possibly interacts with DNA via intercalation and minor groove binding. The studies provide evidence that BDDE has potential application in the control of gray mold after fruit harvest and the compound could serve as a candidate or lead template for rational drug design and for the development of antifungal agents.     

80%腐霉利WP对葡萄灰霉病防效试验

针对不同浓度80%腐霉利WP进行葡萄灰霉病的田间防效试验研究。结果表明:在葡萄灰霉病发病初期,公顷用药量(有效成分)333-500mg/kg兑水750kg,对葡萄灰霉病有较好的防治效果。喷药间隔期为7d,共喷2次。药后7d防治效果在77.06%-82.34%之间,对葡萄生长安全。     

利迪链霉菌A02诱导番茄抗灰霉病作用机制研究——对植株防御酶系的影响

利用利迪链霉菌生防菌株A02发酵液和番茄灰霉病菌对番茄植株进行诱导和接种处理,利用分光光度法测定处理前和处理后1~5 d番茄叶片组织的主要防御酶系——苯丙氨酸解氨酶、过氧化物酶、过氧化氢酶和多酚氧化酶的活性变化。试验结果显示,不接种灰霉病菌而单独诱导处理、接种灰霉病菌后诱导处理和诱导处理后接种灰霉病菌这3种处理都能提高番茄植株各防御酶系的活性,后者酶活性峰值最高,对番茄植株灰霉病的抑制作用也最明显,控制效果达94.92%。     

烟剂防治贮藏期猕猴桃灰霉素之效果初探

灰霉病是猕猴桃贮藏期的重要病害，严重影响猕猴桃商品价值与经济效益。采用烟剂对贮藏期猕猴桃灰霉病（Botrytis cinerea）进行了毒力与防效研究，结果表明，3种烟剂对防治贮藏期猕猴桃灰霉病均具有较好的效果，其中烟剂2号效果好于其他2种烟剂。