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1.
油菜菌核病菌抗腐霉利菌株的生理生化特性及抗药机制初步分析 总被引：3，自引：0，他引：3
通过室内紫外线和药剂诱导,获得多株高抗腐霉利油菜菌核病菌(Sclerotiniasclerotiorum)突变体。与野生亲本菌株相比,抗性突变株(EC50800μg/mL)在高糖(40g/L蔗糖)和高盐(5g/LNaCl)培养基上生长缓慢,表明对高渗透压比较敏感;菌丝相对电导率较高,显示细胞膜透性增大,胞内电解质渗出较多。试验还发现,在含药培养液中,亲本菌株菌丝内甘油大量合成和积累,增加462.45%,而抗药突变株甘油含量仅稍有增加或有所下降,说明抗腐霉利突变株对外界渗透压的调节能力较低。根据已报道组氨酸激酶(HK)基因序列设计特异引物,经PCR扩增和测序,获得油菜菌核病菌HK基因保守区域序列1605bp。抗、感腐霉利菌株HK基因保守区域在第45位、第81位和第625位碱基不同,但编码的氨基酸一致。因此,油菜菌核病菌对腐霉利的抗性及抗药菌株的高渗敏感性与HK基因保守区域碱基突变无关。 相似文献
2.
为了明确油菜菌核病菌对新型杀菌剂嘧菌环胺的敏感性和该药剂与其它杀菌剂的交互抗性,采用菌丝生长速率法测定江苏省不同地区的53个油菜菌核病菌菌株对嘧菌环胺的敏感性,并测定对嘧菌环胺不同敏感性的10个菌株对菌核净、异菌脲、腐霉利、多菌灵、咪鲜胺和戊唑醇等杀菌剂的敏感性。结果表明,菌株间对嘧菌环胺的敏感性差异显著, EC50（抑制中浓度）值在0.0342～1.087 6μg/mL之间;通过EC50值相关性分析,油菜菌核病菌对嘧菌环胺与上述杀菌剂之间不存在交互抗性。 关 相似文献
3.
江苏省油菜菌核病菌对多菌灵的敏感性 总被引：6，自引：0，他引：6
为监测目前油菜菌核病菌对多菌灵抗性现状，对从江苏省各地采集的油菜菌核病病原菌菌株以及海安、苏州和高淳三地的油菜菌核病病原菌田间群体菌株进行了多菌灵的敏感性测定。结果表明，江苏省油菜菌核病菌对多菌灵的抗药性已经产生，不同地区菌株对多菌灵的抗性比率不同。在苏州的田间菌株群体中抗性菌株的比率达到28.12%，而在高淳等地的菌株中没有检测到抗性菌株的存在。抗性菌株都表现为高抗，其EC50 >100µg／ml。对抗性菌株的β-微管蛋白基因进行PCR扩增和酶切的结果表明，所有抗性菌株的β-微管蛋白基因的198位都发生突变，从而导致油菜菌核病菌对多菌灵抗性的产生。从江苏省范围来看，继续使用多菌灵防治油菜菌核病菌可能会导致抗性频率上升、抗性范围扩大。 相似文献
4.
室内毒力测定结果表明，植物源化合物奥麦丁锌（ZPT）对油菜菌核病菌菌丝生长具有显著的抑制作用， EC50值为1.5 µg/mL。ZPT在离体油菜叶片上对油菜菌核病具有明显的防病效果。25%奥麦丁锌可湿性粉剂 200、500µg/mL对油菜叶片菌核病病斑扩展抑制率分别达到83.2%和100%。田间药效试验结果表明， 25%奥麦丁锌可湿性粉剂100克/666.7m2兑水喷雾，对油菜菌核病病具有80%左右的防治效果。 相似文献
5.
油菜菌核病菌对多菌灵的抗药性 总被引：2，自引：0，他引：2
从江苏句容市丘陵山区从未施用多菌灵（MBC）的白菜型油菜苗核病株上，采集了49个Sclerotiniasclerotiorum野生菌株，MBC抑制这些菌株的菌丝生长，平均EC50为0．2198±0．1083μg／ml，最低抑制生长浓度（MIC）值为5．0μg／ml。从镇江农科所油菜育种试验田中采集的S．selerotiorum菌核标样中，发现6个抗MBC的抗性菌株，其EC50值均大于2000μg／ml。抗性菌株对离体油菜叶片的致病力与野生的敏感菌株没有差异。油菜叶片经1000μg／mlMBC溶液浸渍后，敏感菌株对其不能侵染，而抗性菌株对这些叶片的致病力与对未浸药叶片的致病力无明显差异。 相似文献
6.
由镰孢炭疽菌(Colletotrichum falcatum Went.)引起的甘蔗赤腐病是甘蔗上最具毁灭性的病害之一,在病害流行季节能导致严重的产量损失。为了解甘蔗赤腐病原对杀菌剂的敏感性,本研究测定了11种杀菌剂对该病原菌的毒力。结果表明,11种杀菌剂对甘蔗赤腐病菌的毒力存在明显差异。其中,戊唑醇、丙环唑、咪酰胺、苯醚甲环唑、多菌灵等5种药剂对甘蔗赤腐病菌菌丝体生长具有较好的抑制作用,EC50值介于0.227～0.818 μg/mL。其对应EC95值也都小于12 μg/mL,介于1.416～11.339 μg/mL。就敏感性而言,4株赤腐病菌菌株对多菌灵的b值在11种杀菌剂中均为最大。由此表明,甘蔗赤腐病菌对多菌灵的剂量反应变化比其它几种杀菌剂均要敏感。 相似文献
7.
为探明戊唑醇对油菜菌核病的防治效果及作用机制,采用生物测定方法,研究戊唑醇的室内毒力、油菜菌核病菌(Sclerotinia sclerotiorum)的菌丝干重、菌丝蛋白质含量、菌核萌发、菌核致病力和菌丝体细胞膜电导率。结果表明:戊唑醇对油菜菌核病菌具有极强的抑菌作用,EC50和EC90值分别为1.3μg/mL和11.2μg/mL;用戊唑醇处理后,菌丝体干重差异显著,蛋白质含量、菌核萌发率和致病力均随处理浓度的提高而降低;戊唑醇对菌丝体电导率无影响,但对菌丝体的生长有抑制作用。表明戊唑醇通过抑制菌丝干重、菌核萌发率、蛋白质含量和致病力而控制病害发生。 相似文献
8.
采用菌丝生长速率法测定了12种杀菌剂对3株橡胶树褐根病菌的抑菌能力。结果表明：百菌清、腈菌唑、咪鲜胺、三唑酮、戊唑醇、异菌脲、抑霉唑、十三吗啉、丙环唑9种药剂对橡胶树褐根病菌的毒力较强,抑菌效果较好,对橡胶树褐根病菌的EC50在0.013 2～2.972 6 μg/mL,其中丙环唑和戊唑醇的EC50均小于0.1 μg/mL,对橡胶树褐根病菌的抑制效果最佳;嘧菌酯、甲基硫菌灵的效菌效果较差;多菌灵对褐根病菌的抑制效果最差,3株褐根病菌的EC50在138.655 0～492.298 2 μg/mL。 相似文献
9.
为了筛选有效防治药剂,在室内采用菌丝生长速率法测定了10种杀菌剂原药对橡胶树白根病菌的室内毒力。结果表明：戊唑醇、腈菌唑、丙环唑、抑霉唑、三唑酮、咪鲜胺、嘧菌酯、十三吗啉8种药剂对橡胶树白根病菌均具有较高的敏感性,抑菌效果较好,其EC50在0.017 7～6.013 6 μg/mL,其中戊唑醇的毒力最强,EC50为0.017 7 μg/mL;腈菌唑、丙环唑、抑霉唑的抑制作用较强,其EC50分别为0.027 8、0.045 6和0.077 3 μg/mL。甲基托布津抑菌效果最差,EC50为41.299 0 μg/mL。 相似文献
10.
20种植物提取物对芒果炭疽菌的抑制作用 总被引：10，自引：0，他引：10
研究了16科20种（其中12种为中草药）植物的丙酮提取物对芒果炭疽病菌株的抑制作用,初步分析了利用植物源农药解决芒果炭疽病抗药性问题的可能性.结果表明,同一药物在不同浓度下作用效果可能存在较大的差异.芒果炭疽病抗药性菌株对供试植物丙酮提取物没有明显的抗药性,100mg/mL（每mL含100mg干物质的提取物）浓度下石菖蒲、艾草、阳春砂、益智、飞机草等植物在芒果炭疽菌抗药性菌株室内试验中其作用效果明显优于1000 mg/L多菌灵,其中石菖蒲丙酮提取物对芒果炭疽病菌敏感菌株（ZJS）、抗药性菌株（ZJR）有效中浓度EC50分别为5.91,4.06 mg/mL,艾草丙酮提取物对芒果炭疽病菌敏感菌株（ZJS）、抗药性菌株（ZJR）有效中浓度EC50分别为9.24,14.53 mg/mL. 相似文献
11.
Since the 1980s wheat sharp eyespot (WSE) caused mainly by Rhizoctonia cerealis has become one of serious diseases of wheat in China. In this study, the sensitivity of 89 R. cerealis isolates to different fungicides was evaluated using mycelial growth inhibition assays. The results showed that all R. cerealis isolates tested were sensitive to iprodione, difenoconazole and fludioxonil with mean EC50 (effective concentration that results in 50% of mycelial growth inhibition) values of 0.419, 0.062 and 0.033 μg/ml, respectively. To evaluate the risk of fungicide resistance in R. cerealis, an attempt was made to induce resistant mutants in the laboratory. Although difenoconazole- and fludioxonil-resistant mutants were not obtained, we obtained seven independently iprodione-resistant (IR) mutants from 89 parental isolates. The EC50 values for these IR mutants were greater than 100 μg/ml, whereas those for the original wild-type counterparts were less than 1 μg/ml. After having been subcultured on PDA for 10 generations, the IR mutants did not show any decrease in resistance to iprodione. Additionally, these IR mutants also showed resistance to fludioxonil but remained sensitive to difenoconazole. Osmotic sensitivity tests showed that the IR mutants were hypersensitive to osmotic stress generated by NaCl. Inoculation tests showed that all the IR mutants lost their ability to infect the host plant. Taken together, these results indicate that the current population of R. cerealis is sensitive to these fungicides and a fitness cost is associated with iprodione-resistant mutants of R. cerealis in both osmotic stress and pathogenicity. The information obtained in this study is useful in monitoring and managing fungicide resistance in R. cerealis populations in China. 相似文献
12.
13.
Botrytis cinerea, the fungal pathogen responsible for causing gray mold in tomatoes, frequently exhibits multiple fungicide resistance. In this study, the sensitivity to carbendazim (Car), diethofencarb (Die), procymidone (Prc), and pyrimethanil (Pyr) was determined for 263 isolates of B. cinerea from diseased fruit and leaves of tomato plants from 87 commercial greenhouses in Henan Province of China during 2013 and 2014. Of the isolates tested, 89%, 93%, 85%, and 86% were resistant to Car, Die, Prc, and Pyr, respectively. Twelve phenotypes were found having different sensitivity patterns, and multi-fungicide resistance was found to one, two, three or four fungicides. The percentage of multiple fungicide resistant isolates (CarRDieRPrcRPyrR) was 68%. Mycelial growth, spore production, and mycelial dry weight were not significantly different between resistant and sensitive phenotypes of the B. cinerea isolates. However, the virulence of CarSDieRPrcSPyrS isolates was higher than that of the other fungicide-resistance phenotypes. All of the carbendazim and diethofencarb resistant phenotypes carried a point mutation at codon 198 (E198A or E198K) or 200 (F200Y) in the β-tubulin gene, and all of the procymidone resistant phenotypes carried point mutations at codons 369 (Q369P) and 373 (N373S) in the Bos1 gene. These results provided important reference data for assessment of resistance risk of B. cinerea isolates from commercial tomato transplants in Henan Province, indicating the existence of a high frequency of resistance to carbendazim, diethofencarb, procymidone, and pyrimethanil revealing the necessity of a more integrated control of gray mold. 相似文献
14.
Field strains of Botryotinia fuckeliana were isolated from diseased grape berries which were collected at the harvest, between 1993 and 1997, from French vineyards located in Alsace, Armagnac, Bordeaux, Champagne and Loire Valley. According to the inhibitory effects of fungicides towards spore germination, germ-tube elongation and mycelial growth, several phenotypes could be characterized. Thus, two types of benzimidazole (e.g. carbendazim, thiabendazole)-resistant strains were detected; negative cross-resistance towards diethofencarb, diphenylamine and dicloran was found only in one type. Most dicarboximide (e.g. iprodione, procymidone, vinclozolin)-resistant strains were also weakly resistant to aromatic hydrocarbon fungicides (e.g. chloroneb, dicloran, tolclofos-methyl) but remained sensitive to phenylpyrroles (e.g. fenpiclonil, fludioxonil). However, in some other dicarboximide-resistant strains, resistance was observed either as being restricted to dicarboximides or as extending weakly to phenylpyrroles. Towards anilinopyrimidines (e.g. cyprodinil, mepanipyrim, pyrimethanil), three resistant phenotypes have been identified. In the most resistant one, resistance was restricted to anilinopyrimidines, whereas in the others, resistance extended to various other groups of fungicides including dicarboximides, phenylpyrroles, sterol biosynthesis inhibitors (e.g. tolfanate, prochloraz, tebuconazole) and the hydroxyanilide derivative, fenhexamid. According to the pattern of cross-resistance, two phenotypes were characterized within these multifungicide-resistant strains. In vitro tests conducted with fenpropimorph, fenpropidin and spiroxamine, revealed the existence of strains highly susceptible to these sterol Δ14- reduction inhibitors. This property was correlated with a decreased sensitivity towards fenhexamid. 相似文献
15.
This work determined the sensitivity of field populations of Sclerotinia sclerotiorum (Lib.) de Bary before exposure to the fungicide fludioxonil (= baseline sensitivity) and assessed the risk of fludioxonil resistance. The mean EC50 (Effective Concentration) and Minimum inhibitory concentration (MIC) values for fludioxonil based on inhibition of mycelial growth of 120 wild-type isolates were 0.015 ± 0.005 μg/ml and <0.05 μg/ml, respectively. Positive cross-resistance was not detected between fludioxonil and benzimidazole fungicides but was detected between fludioxonil and dicarboximide fungicides which are considered as high resistance risk fungicides by FRAC, even though these fungicides have different molecular structures. By growing wild-type isolates on potato dextrose agar (PDA) containing sublethal concentrations of the fungicide, we obtained four fludioxonil-resistant mutants with resistance factors (EC50 resistant/EC50 sensitive phenotypes) >2000. The laboratory fludioxonil mutants were less fitter than their parental isolates in terms of mycelial radial growth, pathogenicity and sclerotial production. Moreover, on PDA amended with NaCl, the laboratory fludioxonil mutants grew more slowly than their fludioxonil-sensitive parents, especially at lower concentrations of NaCl. According to the fitness of mutants and the cross-resistance between fludioxonil and dicarboximide fungicides, phenylpyrroles can be considered to pose a moderate resistance risk. In a field trial, fludioxonil provided greater control (over 90% disease control) of S. sclerotiorum than iprodione. 相似文献
16.
The ascomycete fungus Sclerotinia sclerotiorum is a devastating necrotrophic plant pathogen with an unusually broad host range and worldwide distribution. The benzimidazole fungicide carbendazim has been widely used to control S. sclerotiorum in China for more than three decades and high levels of carbendazim resistance have been reported in eastern China. In this study, carbendazim sensitivity was assessed in a total of 5042 field isolates of S. sclerotiorum collected from different geographical regions of China from 2008 to 2013. Results showed that no carbendazim resistant isolates could be detected in northwestern and northeastern China. In 2013, 0.77% and 0.72% of the field isolates assayed were highly resistant to carbendazim in Hunan and Hubei provinces of central China, respectively. In Anhui province of eastern China, the frequencies of carbendazim resistance were 18.18%, 7.05% and 7.25% in 2008, 2011 and 2012, respectively. The decrease in frequency of carbendazim resistance in Anhui province from 2008 to 2012 was statistically significant (P = 0.001). Nevertheless, no significant differences (P ≥ 0.16) were found in fitness parameters such as mycelial growth on PDA media, virulence to oilseed rape plants and oxalic acid production between carbendazim resistant and sensitive isolates. A negative cross resistance pattern was detected between carbendazim and diethofencarb. Mixture of carbendazim and diethofencarb (4:1) applied at 200 μg/mL provided 100% and 91.5% preventive efficacy against carbendazim resistant and sensitive isolates, respectively, and 87.1% and 81.7% curative efficacy against resistant and sensitive isolates, respectively. 相似文献
17.
Fenhexamid is a hydroxyanilide fungicide with excellent performance against Botrytis cinerea but also effective against Monilinia spp. which cause brown rot disease in apple and stone fruit. A total of 75 Monilinia laxa field isolates were utilized to determine baseline sensitivity while a number of fenhexamid-resistant laboratory mutants were used to evaluate the resistance risk associated with the longevity of the effectiveness of fenhexamid. Fenhexamid was found to be highly effective against all field isolates. EC50 values ranged from 0.02 to 1 μg mL−1 and were distributed unimodaly around an average of 0.1 μg mL−1. M. laxa laboratory strains with moderate and high resistance levels to fenhexamid were isolated after UV mutagenesis. All fenhexamid-resistant strains showed parental sensitivity to carbendazim, iprodione, fludioxonil, pyraclostrobin, flusilazole and prochloraz. Interestingly, some of the mutant strains were also resistant to tridemorph, fenpropimorph and spiroxamine. Studies on fitness parameters of fenhexamid-resistant strains revealed a fitness cost on sporulation and pathogenicity but not on mycelial growth. These results suggest that fenhexamid should be a good alternative site-specific fungicide for the control of brown rot disease caused by M. laxa. However, appropriate anti-resistance strategies should be considered to ensure the successful commercial use of fenhexamid in the long run. 相似文献
18.
Cucurbit downy mildew caused by the oomycete pathogen Pseudoperonospora cubensis is a devastating disease that is distributed worldwide and affects cucumber in open fields and greenhouses. Fluopicolide, which was a novel systemic fungicide and was released in 2008, it is very effective in controlling downy mildew on cucumber and grape, potato late blight and pepper Phythophthora blight and reduces the loss caused by the diseases, but so far the potential for P. cubensis to develop resistance to fluopicolide has not been investigated. Hence, a laboratory study was undertaken to assess the risk of P. cubensis developing resistance to fluopicolide. Baseline sensitivity to fluopicolide was determined by using 75 P. cubensis isolates collected from cucumber-growing greenhouses in Hebei province, where no fluopicolide had been used for control of cucumber downy mildew before. Values of effective concentrations for 50% inhibition (EC50) of sporulation ranged from 0.02 to 0.40 μg ml−1 and were distributed as a unimodal curve, indicating that all 75 isolates were sensitive to fluopicolide. Sporangia of nine sensitive isolates were ultraviolet (UV)-irradiated, and four fluopicolide-resistant mutants were acquired at a mutation frequency of 7.4 × 10−7. Seven mutants resistant to fluopicolide were obtained from seven isolates by sporangia adaptation on fluopicolide-treated leaves of cucumber. The EC50 values for all eleven fluopicolide-resistant mutants ranged from 3.37 to 13.06 μg ml−1 with mean resistance factors of 7.9–118.0. After 10 sporangia transfers on fungicide-free leaves of cucumber, all eleven resistant mutants remained resistant to fluopicolide with mean resistance factors of 8.2–81.3. Seven resistant mutants from the selection for resistance and one resistant mutant from UV mutagenesis exhibited stable resistance; however, the other three resistant mutants from UV irradiation became significantly less resistant. Compared to their respective sensitive parents, the eleven resistant mutants exhibited diversity in latent period, infection frequency, lesion extension and sporulation ability. Five out of the eleven resistant mutants exhibited prolonged latent period and three out of the eleven resistant mutants provided decreased infection frequency (IF) compared to their respective parents, indicating that in some cases, resistance mutation might affect the latent period and IF of P. cubensis. There were significant differences in pathogenicity and ability to produce sporangia, but this seemed not to be caused by resistance mutation. No cross-resistance was detected between fluopicolide and azoxystrobin, metalaxyl, dimethomorph, or cymoxanil. In all, there could be a moderate to high risk of field populations of P. cubensis developing resistance to fluopicolide, and populations of P. cubensis should be monitored regularly for their shift of sensitivity over years of application. 相似文献
19.
核盘菌接种不同抗性油菜后致病力分化的研究 总被引：1，自引：0，他引：1
为了解核盘菌致病力分化与寄主油菜品种抗性的关系,采用茎秆牙签接种法将单一核盘菌菌株接种至46份抗性表现不同的油菜品种茎秆上,再从46个接种茎秆内收集形成的菌核进行纯化和培养,获得46株核盘菌菌株,进而采用两种方法(室内离体叶片接种法和离体茎秆接种法),分别测定这46株核盘菌菌株对甘蓝型油菜品种黔油16号的致病能力。结果表明:不同核盘菌菌株在黔油16号上所致的病斑长度明显不同;相同来源菌株经两种接种方法所致病斑在长度上反映出的致病趋势一致,基本表现为中感﹥高感﹥低感﹥抗性。即来自油菜品种为"抗"类型上的对应菌株其致病力最弱,而来自"中感"类型上的对应菌株其致病力最强。结果说明核盘菌致病力强弱分化与油菜品种的抗性有关系。 相似文献
20.
Oxathiapiprolin is a new fungicide active against oomycetes. In vitro assays and field studies were conducted to examine the effect of oxathiapiprolin on Phytophthora nicotianae (Pn), the causal agent of black shank. The efficacy of oxathiapiprolin on mycelial growth, sporangia production, zoospore motility, and zoospore germination was assessed with four Pn isolates. EC50 values were low ranging from 0.0039 to 0.0049 μg a.i./mL for mycelial growth, 0.00052–0.00081 μg a.i./mL for sporangia production, 0.0035–0.0051 μg a.i./mL for encysted zoospore germination, and 0.0055–0.0166 μg a.i./mL for zoospore motility. Sixty six Pn isolates, 60 from tobacco and six from ornamental plants were examined for sensitivity to oxathiapiprolin at 1 μg a.i./mL. Mycelial growth at 1 μg a.i./mL was observed in only one isolate from tobacco whereas the six Pn isolates from ornamental plants five of which were resistant to mefenoxam at 100 μg a.i./mL, were found to be sensitive to oxathiapiprolin. The efficacy of oxathiapiprolin against black shank was assessed in three field studies in North Carolina. Treatments of oxathiapiprolin were equal or superior to mefenoxam against black shank in each field study. Our results suggest that oxathiapiprolin is a highly efficacious fungicide against P. nicotianae, and will be a useful tool in controlling black shank of tobacco. 相似文献