Interaction of virus-infected celery and Septoria apiicola

Inoculation of celery plants with viruses CV036 (celery mosaic) and CV506 (parsnip yellow fleck) decreased blight on leaves inoculated later with Septoria apiicola by 17–39% and 54–91%, respectively. There was a significant negative correlation between the amount of blight and the furanocoumarin content of the celery petioles. The antifungal activity of these furanocoumarins was demonstrated by their in vitro inhibition of the germination of spores of S. apiicola and Botrytis cinerea . Scanning electron microscopy of virus-infected leaves sprayed with spores of S. apiicola also showed slight but significant reductions in percentage germination and in germ-tube length, and considerable reductions in the proportion of germ-tubes which produced an appressorium, compared with spores on virus-free leaves.     

Inhibition of sterol biosynthesis in cell-free extracts of Botrytis cinerea by prochloraz and prochloraz analogues

The sensitivity of cytochrome-P450-dependent sterol 14α-demethylase (P450_14DM) to prochloraz and several prochloraz analogues was studied in a cell-free assay of Botrytis cinerea Pers. ex Fr. The EC₅₀ values (concentrations which inhibited radial growth of B. cinerea by 50%) of the compounds tested ranged from 3.3 × 10 ?8 to 1.7 × 10 ?5 M. The IV₅₀ values (concentrations which inhibited cell-free C₄-demethyl sterol synthesis by 50%) in cell-free assays of B. cinerea ranged from 2.6 × 10 ?9 to 4.4 × 10 ?7 M. Ranking compounds in terms of their relative inhibitory potencies showed quite similar trends to the order of fungitoxicity, but the IC₅₀ values did not quantitatively reflect the differences in toxicity. Therefore, the differential inhibition of cell-free P450_14DM activity by these compounds cannot fully account for their differences in activity towards B. cinerea. Additional mechanisms must be involved. The compounds tested were generally more potent in the B. cinerea assay than in similar assays developed for Penicillium italicum Wehmer and, in particular, Saccharomyces cerevisiae Meyen. This correlated with the relatively higher activity of most test compounds to B. cinerea. Results suggest that the cell-free assay of B. cinerea is more useful to evaluate candidate fungicides as inhibitors of sterol 14α-demethyiase activity than similar assays from model organisms. The present study confirms that the affinity of prochloraz analogues for P450_14DM depends on the nature of the N-1 substituent of the imidazole and the azole ring. It was also found that addition of an amino group at C-2 of the imidazole moiety of prochloraz gave a compound (6) which inhibited 4, 4-demethyl sterol biosynthesis in B. cinerea at a different site from the P450_14DM. This was confirmed by the observation that laboratory-generated triadimenol-resistant isolates of B. cinerea showed reduced sensitivity to triadimenol and prochloraz, but not to compound 6.     

Use of Selenate-Resistant Strains as Markers for the Spread and Survival of Botrytis cinerea Under Greenhouse Conditions

ABSTRACT Botrytis cinerea marked strains combining traits of fungicide resistance or sensitivity (carbendazim, iprodione) with resistance to selenate were created and assessed for use in studying the dispersal of B. cinerea and its survival inside plant tissue under greenhouse conditions. Marked strains differed in their ability to cause lesions and to disperse in the greenhouse. A strain that was the most aggressive in infecting plants was also the most successful in spreading across the greenhouse. Following 7 to 14 days of exposure to marked inoculum, about 90% of plants showed quiescent B. cinerea infection with no significant difference between hosts or seasons. However, in a warm season, most of the plants were infected with wild-type B. cinerea, whereas most of the winter-recovered B. cinerea strains were of the marked phenotype, showing the importance of local inoculum from within the glasshouse in winter. The air of the greenhouse contained the same population of marked B. cinerea in warm and in cold periods, whereas the total population was significantly higher in summer. In the warm season, mycelium of B. cinerea inside plant debris lost viability within 3 to 4 months, whereas it stayed viable for 4 months in the winter (December to March) and started to lose viability in April.     

A Laboratory Simulation for Vectoring of Trichosporon pullulans by Conidia of Botrytis cinerea

ABSTRACT A mechanism that could contribute to the suppression of Botrytis cinerea during pathogen sporulation was examined in this study. Yeasts capable of binding to B. cinerea were formulated with a cellulose carrier and applied to sporulating colonies of the pathogen. The particles from this yeast/cellulose product attached to B. cinerea conidia in the sporulating colony. Inoculum from treated colonies was harvested and applied to tomato stem tissue to test for subsequent pathogenicity. Disease development from inoculum obtained from cultures that had been treated with Trichosporon pullulans was significantly retarded (P = 0.0001) compared with cellulose-only controls. However, between 5 and 11% of conidia applied were attached to yeast cells. The removal of conidia not attached to yeast resulted in inoculum composed of >90% of conidia attached to yeast, and from this inoculum, disease development was significantly retarded (P < 0.05). When inoculum from treated B. cinerea colonies was applied to nutrient limiting agar and then incubated, the B. cinerea conidia germinated, and yeast cells infested the new hyphal growth. Constraints of the formulation of the yeast used in this study, and the implications of this vectoring approach for the suppression of B. cinerea during pathogen sporulation are discussed.     

Resistance to fungicides which inhibit ergosterol biosynthesis in laboratory strains of Botrytis cinerea and Ustilago maydis

The strains of Botrytis cinerea or Ustilago maydis selected on fenarimol, triarimol, or triadimefon were also resistant to the other inhibitors of sterol C-14 demethylation; the sterol composition of the strains was normal. Among the isolates of U. maydis resistant to dodemorph, fenpropidin, fenpropimorph and tridemorph, some were resistant to the 15-azasteroid A 25822B and did not contain ergosterol. The other strains remained sensitive to A 25822B and had a normal sterol composition. All the resistant isolates and the wild-type were inhibited to the same extent by nystatin and pimaricin.     

Development of a polyclonal antibody-based immunoassay for the early detection of Sclerotinia sclerotiorum in rapeseed petals

A serological test has been developed that allows the early detection of infection of young petals by Sclerotinia sclerotiorum , an important pathogen of rapeseed. Two steps were required to obtain an antiserum sufficiently specific for S. sclerotiorum. Soluble mycelial extracts of S. sclerotiorum were used to produce the first generation polyclonal antiserum. This was not specific for S. sclerotiorum in double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and allowed the screening of cross-reacting fungal species such as Botrytis cinerea , a pathogen commonly present on rapeseed petals. Using a polyclonal anti- B. cinerea serum enabled the absorption, by serial cycles, of S. sclerotiorum antigens common to B. cinerea. Residual antigens were then used as immunogens for the production of two second generation antisera (S1 and S2) which were then tested by DAS-ELISA. Cross-reactions with B. cinerea decreased with purification cycles of the immunogen whereas Cross-reactions with some unrelated fungi slightly increased. S. sclerotiorum and B. cinerea were distinguishable using antiserum S2.     

齐墩果酸肟醚类化合物的合成及杀菌活性

为了开发潜在的氨基葡萄糖-6-磷酸合成酶（GlmS）抑制剂和杀菌剂,设计并合成了30个齐墩果酸肟醚类化合物,其中29个为新化合物,其结构均经1H NMR、13C NMR和高分辨质谱确证。采用Elson-Morgan法和菌丝生长速率法,分别测定了目标化合物对GlmS的抑制活性和杀菌活性。结果表明:在0.35 mmol/L下,大部分目标化合物对GlmS表现出一定的抑制活性,其中,化合物A-01、A-02、A-04、C-04和C-05对GlmS的抑制率在30%左右;部分化合物在50 μg/mL下对油菜菌核病菌Sclerotinia sclerotiorum（Lib.）de Bary、番茄灰霉病菌Botrytis cinerea Pers. 和稻瘟病菌Pyricularia oryzae Cav. 具有较好的杀菌活性,其中,化合物A-01、A-02、A-04、A-05和B-02对油菜菌核病菌的抑制率在88%左右,具有进一步研究的价值。     

The Use of a Radioimmunosorbent Assay for Botrytis cinerea1

A radioimmunosorbent assay was developed for Botrytis cinerea which can be used to detect as little as 100 ng of Botrytis mycelium (dry weight). Of 22 fungi tested in the assay, all significant reaction was restricted to members of the Sclerotiniaceae. No reaction was obtained with representative isolates of Aspergillus, Alternaria or Peiticillium. Other Botrytis species gave the most reaction relative to B. cinerea. and related genera such as Monilinia and Sclerotinia yielded small reactions. The assay can be used to detect fi. cinerea infection of grape berries when as little as 0.1 % of homogenate from infected fruit is mixed with homogenate from sound fruit to simulate a minor infection. The assay of free run juice from various lots of grapes was highly correlated with visual assessments of infection in the field. Pursuant to various theories concerning bloom time infection, the assay was used to analyse the B. cinerea content of immature berry tips and floral debris; however, no evidence of such colonization was obtained.     

五种杀菌剂胁迫下灰葡萄孢产孢所需碳源种类分析

灰葡萄孢是引起作物灰霉病的病原菌,分生孢子是其传播的主要载体.本文采用代谢技术分析了灰葡萄孢对Biolog FF板碳源的利用及其产孢情况,并测定了在多菌灵、丙环唑、嘧霉胺、异菌脲和咪鲜胺5种杀菌剂胁迫下灰葡萄孢产孢所需碳源种类.结果表明:糖类、氨基酸类等92种碳源均能被灰葡萄孢代谢,其中,杏仁苷、L-阿拉伯糖等35种碳...     

Antagonism of Trichoderma harzianum ETS 323 on Botrytis cinerea Mycelium in Culture Conditions

ABSTRACT Previous studies have shown that the extracellular proteins of Trichoderma harzianum ETS 323 grown in the presence of deactivated Botrytis cinerea in culture include a putative l-amino acid oxidase and have suggested the involvement of this enzyme in the antagonistic mechanism. Here, we hypothesized that the mycoparasitic process of Trichoderma spp. against B. cinerea involves two steps; that is, an initial hyphal coiling stage and a subsequent hyphal coiling stage, with different coiling rates. The two-step antagonism of T. harzianum ETS 323 against B. cinerea during the mycoparasitic process in culture was evaluated using a biexponential equation. In addition, an l-amino acid oxidase (Th-l-AAO) was identified from T. harzianum ETS 323. The secretion of Th-l-AAO was increased when T. harzianum ETS 323 was grown with deactivated hyphae of B. cinerea. Moreover, in vitro assays indicated that Th-l-AAO effectively inhibited B. cinerea hyphal growth, caused cytosolic vacuolization in the hyphae, and led to hyphal lysis. Th-l-AAO also showed disease control against the development of B. cinerea on postharvest apple fruit and tobacco leaves. Furthermore, an apoptosis-like response, including the generation of reactive oxygen species, was observed in B. cinerea after treatment with Th-l-AAO, suggesting that Th-l-AAO triggers programmed cell death in B. cinerea. This may be associated with the two-step antagonism of T. harzianum ETS 323 against B. cinerea.     

Development of a monoclonal antibody-based immunodetection assay for Botrytis cinerea

Three hybridoma cell lines secreting antibodies that specifically recognize Botrytis cinerea and B.fabae , but not B. allii, have been raised from splenocytes of mice immunized with a low molecular-weight fraction (30 kDa) from surface washings of B. cinerea. Antibodies from these cell lines have been used to develop an antigen-based elisa test that will detect B. cinerea in strawberries. This monoclonal antibody immunoassay detection assay should prove useful to both the cut-flower and wine industries. Supernatants from the three specific cell lines recognize mycelial fragments, saline extracts of mycelia and germinating conidia by both ELISA and immunofluorescence. Recognition of non-germinating spores is poor. Supernatants from the specific cell lines did not recognize other fungi normally involved in post-harvest spoilage of fruits and vegetables. Supernatants from KH4 gave the lowest background values with healthy tissue. Indirect evidence from heat, protease and periodate treatment of the antigens indicates that antibodies from all three specific cell lines are recognizing carbohydrate epitopes on a glycoprotein.     

Possible Role of Colonization and Cell Wall-Degrading Enzymes in the Differential Ability of Three Ulocladium atrum Strains to Control Botrytis cinerea on Necrotic Strawberry Leaves

ABSTRACT Ulocladium atrum (strain 385) consistently reduced Botrytis cinerea sporulation on necrotic fragments of strawberry leaves. On these tissues, two strains of U. atrum (isolates 18558 and 18559) showed lower antagonistic activities than the reference strain 385. Colonization of strawberry leaflets by the three U. atrum strains appeared similar in the absence of B. cinerea, whether quantified by chitin or immunological assays. The second method (based on anti-U. atrum antibodies) revealed that strawberry leaflet colonization by U. atrum 385 was better than by the other U. atrum strains in the presence of B. cinerea. An immunoassay using anti-B. cinerea antibodies revealed that the colonization of B. cinerea in tissues was lower in the presence of U. atrum 385 than with the two other U. atrum strains. The enzymatic activities produced by U. atrum 385 during the colonization phases of necrotic tissues were compared to B. cinerea and U. atrum strains 18558 and 18559. U. atrum 385 had the highest lipase, pectate lyase, and cellobiase activities while B. cinerea had the highest endo-beta-1,4-glucanase activity. The study of lytic activities hydrolyzing the fungal cell wall revealed higher beta-1,3-glucanase activity with U. atrum 385, which was stimulated by B. cinerea on necrotic strawberry leaflets. These results suggest that plant and fungal cell wall-degrading enzymes produced by U. atrum 385 may play a complementary role in the competitive colonization of dead strawberry leaves against B. cinerea.     

Factors affecting symptom production by latent Botrytis cinerea in Primula×polyantha

Latent infection by Botrytis cinerea was frequently detected in young Primula × polyantha (horticultural hybrid polyanthus) plants. Genetically marked isolates were used to demonstrate that conidial inocula applied to young plants generally did not result in disease appearing on the leaves until plants flowered, regardless of when plants were inoculated. The severity of disease was proportional to the length of each day spent at 100% relative humidity during the latent period, regardless of time or form of inoculum. Plants with a prior B. cinerea infection were more susceptible to further infection and also showed symptoms of B. cinerea infection more quickly. Bacteria found to be associated with B. cinerea increased the likelihood of B. cinerea symptoms being seen on the plant, but did not directly assist infection.     

Control of Postharvest Decay of Apple Fruit with Candida saitoana and Induction of Defense Responses

ABSTRACT The ability of Candida saitoana to induce systemic resistance in apple fruit against Botrytis cinerea was investigated. To separate the antagonistic activity of C. saitoana from its ability to induce resistance, the antagonist and the pathogen were applied in spatially separated wounds. In fresh apples, C. saitoana applied 0 or 24 h before inoculation with B. cinerea showed no effect on lesion development caused by B. cinerea. When applied 48 to 72 h preinoculation with B. cinerea, however, C. saitoana reduced lesion diameter by more than 50 and 70%, respectively, compared with wounding. C. saitoana had no effect on lesion development on stored apples, regardless of the lag period between yeast treatment and inoculation with B. cinerea. In addition to inducing systemic resistance, C. saitoana increased chitinase and beta-1,3-glucanase activities with a higher accumulation in fresh than in stored apples. In fresh apples, the onset of systemic resistance to B. cinerea coincided with the increase in chitinase and beta-1,3-glucanase activity in systemically protected tissue. These studies show that C. saitoana is capable of inducing systemic resistance in apple fruit and indirectly suggest that antifungal hydrolases are involved in the observed systemic protection.     

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%。     

N-(2,4,5-三氯苯基)-2-氧代环己烷基磺酰胺对灰葡萄孢的抑制作用

研究了新型环烷基磺酰胺类化合物N-(2,4,5-三氯苯基)-2-氧代环己烷基磺酰胺(简称化合物108)对灰葡萄孢菌丝生长、孢子形成和萌发以及菌核产生等不同生育阶段的抑制作用及其对菌丝致病力和形态结构的影响。结果表明:化合物108对灰葡萄孢菌丝生长和孢子形成及孢子萌发具有明显的抑制作用,其EC50值分别为6.90、4.70和4.11μg/mL;菌核形成受到明显抑制,当药剂质量浓度达20μg/mL时,无菌核产生。经化合物108处理后的灰葡萄孢菌丝致病力下降,40μg/mL处理的菌丝致病力显著低于对照。超微结构观察结果表明,化合物108能导致灰葡萄孢菌丝萎缩、塌陷和变形,菌体细胞壁增厚、皱缩及分层。     

丁香酚对灰葡萄孢的抑制作用研究

丁香酚是从植物中提取的天然化合物。采用菌丝生长速率法测定了其对多种植物病原真菌的抑制作用以及田间分离得到的7株灰葡萄孢Botrytis cinerea对丁香酚的敏感性,同时测定了丁香酚对B.cinerea 03 孢子和菌核的抑制活性。结果显示,丁香酚对多种植物病原真菌均有不同程度的抑制作用;灰葡萄孢不同菌株对丁香酚的敏感性不同,EC50值在29.97 ~83.62 μg/mL之间;丁香酚可抑制灰葡萄孢产孢,但对孢子萌发无影响,可抑制其菌核的产生和萌发。荧光染色结果表明丁香酚能破坏灰葡萄孢菌丝细胞膜。利用原子吸收光谱法和紫外分光光度法分别测定丁香酚处理前后菌丝培养液中K+浓度和OD260值变化,结果显示处理后K+浓度和OD260值均升高。综上所述,细胞膜可能是丁香酚对灰葡萄孢菌丝的作用位点。     

哈茨木霉菌与啶酰菌胺联用对番茄灰霉病菌的增效机制

为验证哈茨木霉菌与啶酰菌胺联用对番茄灰霉病菌的增效作用,采用显微镜观察法观察了菌药联用后哈茨木霉菌和番茄灰霉病菌的菌丝形态,用菌丝生长速率法和圆盘滤膜法测定了菌药联用后哈茨木霉菌挥发性物质、非挥发性物质和粗酶液对番茄灰霉病菌的抑菌活性.结果显示:啶酰菌胺对哈茨木霉菌的菌丝基本无影响,但能使灰霉病菌的菌丝发生间断性溶解;菌药联用后哈茨木霉菌挥发性物质对灰霉病菌的最高抑菌活性为61.17％,而哈茨木霉菌和啶酰菌胺单独对灰霉病菌的抑菌活性分别为48.79％、0.97％,表现增效作用;菌药联用后哈茨木霉菌非挥发性物质和粗酶液对番茄灰霉病菌的抑菌活性未明显增强.研究表明,啶酰菌胺与哈茨木霉菌联用的增效机制是啶酰菌胺导致灰霉病菌的菌丝部分溶解,同时增强了哈茨木霉菌挥发性物质对灰霉病菌的抑菌活性.     

Combinations of Fungicides with Phylloplane Yeasts for Improved Control of Botrytis cinerea on Geranium Seedlings

ABSTRACT Control of Botrytis cinerea on geranium seedlings was evaluated in treatments with phylloplane yeasts in combination with 10 fungicides used to manage Botrytis blight of ornamental plants. Rhodotorula glutinis PM4 significantly reduced the development of lesions caused by B. cinerea on geranium cotyledons; however, yeast biocontrol efficacy was highly variable between trials. Treatment with the yeast in combination with azoxystrobin or trifloxystrobin at one tenth the labeled rate (7.5 mug a.i. ml(-1)) or the full labeled rate (7.5 mug a.i. ml(-1)) reduced lesion development, compared to treatment with the yeast or the fungicide alone. Vinclozolin at half the labeled rate or the full labeled rate (250 or 500 mug a.i. ml(-1)), in combination with R. glutinis PM4, significantly reduced the development of lesions caused by an isolate of B. cinerea resistant to vinclozolin. Copper hydroxide and iprodione at one-tenth the labeled rates, with or without yeast, were highly effective in limiting lesion development. Mancozeb did not increase the biocontrol efficacy of the yeast, and thiophanate-methyl negatively affected the yeast efficacy. Improved disease control was observed in treatments with vinclozolin at the labeled rate and R. glutinis PM4 at cell densities of 5 x 10(5) and 1 x 10(6) cells ml(-1), but not 1 x 10(5) cells ml(-1), on seedlings co-inoculated with B. cinerea in a suspension containing 1 x 10(5) conidia ml(-1). Disease control improved in treatments with combinations of vinclozolin and eight other isolates of R. glutinis, two isolates of R. graminis, and two isolates of R. mucilaginosa. Biocontrol was not observed in treatments with two isolates of R. minuta. The combination of yeast and vinclozolin significantly reduced the germination of conidia of B. cinerea and the growth of R. glutinis PM4 in vitro. All combinations of R. glutinis PM4 with azoxystrobin, trifloxystrobin, or vinclozolin provided highly effective and consistent disease control not observed in treatments with the fungicides alone or the yeast alone.     

鲁北中华剑角蝗生物学特性初步观察

中华剑角蝗（Acrida cinerea Thunb.）是鲁北地区的优势蝗种,为明确中华剑角蝗的发生规律,于2004—2007年通过大田调查与笼内饲养相结合的方法进行了调查研究。结果表明：中华剑角蝗在鲁北地区1年发生1代,以卵在土中越冬,蝗蝻6龄。并对中华剑角蝗的年生活史、历期、生活习性、发生影响因素进行了详述。