海南芒果可可球二孢的致病力及其对多菌灵抗性

从海南5个芒果主产区采集分离芒果蒂腐病菌可可球二孢菌株,采用室内人工接种的方法对110个可可球二孢菌株进行致病力测定,采用区分剂量法和菌丝生长速率法测定其中106个菌株对多菌灵的抗性。结果表明:芒果蒂腐病自然发病率29.37%;人工接种的发病率100.00%,110株可可球二孢菌株中强致病力、中等致病力及弱致病力菌株分别占64.55%、25.45%和10.00%;在106株可可球二孢菌株中,抗性菌株发生频率为52.83%,其中高抗菌株可在含100 mg/L多菌灵培养基上生长,发生频率为45.28%,中抗菌株在含100 mg/L多菌灵培养基上不能正常生长,抗性频率为7.55%;没有发现低抗菌株。多菌灵对可可球二孢田间分离菌株EC_(50)的频率分布为不连续分布,研究结果表明海南地区危害芒果的可可球二孢对多菌灵抗性非常严重。     

辽宁稻瘟病病菌对戊唑醇的敏感性及抗性突变体生物学特性

采用菌丝生长速率法测定了辽宁省109株稻瘟病病菌对戊唑醇的敏感性,并对紫外线照射诱导的抗性突变体的主要生物学特性进行了研究。初步建立了辽宁省稻瘟病病菌对戊唑醇的敏感基线,为(0.383 3±0.026 3)μg/m L。6株抗性突变体的抗药倍数为6.5～19.2倍;相较于亲本菌株,突变体的菌丝生长速率、菌丝干重、产孢量和致病力均明显降低。辽宁省稻瘟病病菌对戊唑醇的敏感性较高,抗性突变体的适合度较低,抗性菌株在自然环境中不易形成稳定群体。     

拟轮枝镰孢对多菌灵的敏感性及抗性菌株生物学性状和交互抗性

为评价玉米穗腐病主要致病菌拟轮枝镰孢Fusarium verticillioides对多菌灵的敏感性，采用菌丝生长速率法测定了采自山东、河北、河南、四川、甘肃、辽宁及宁夏7省(自治区)的168株玉米穗腐病拟轮枝镰孢对多菌灵的敏感性，并对经药剂驯化获得的拟轮枝镰孢抗多菌灵菌株主要生物学性状和交互抗性进行了研究。结果表明:多菌灵抑制拟轮枝镰孢菌丝生长的EC₅₀值在0.013 2~0.774 0 mg/L之间，平均EC₅₀值为(0.220 8 ± 0.143 7) mg/L。敏感性频率分布显示，供试病原菌群体中已出现对多菌灵敏感性下降的亚群体，但其中仍有35.71%的菌株对多菌灵的敏感性频率呈正态分布，因此可将此部分菌株的平均EC₅₀值 (0.081 4 ± 0.028 9) mg/L作为拟轮枝镰孢对多菌灵的相对敏感基线。药剂驯化共获得6株抗性菌株，抗性倍数在5.05~12.22之间。抗性菌株的菌丝生长速率及菌丝干重均低于亲本菌株，表明其抗性菌株的生物适合度有所降低，同时发现其抗药性均不能稳定遗传。室内交互抗性测定结果表明，拟轮枝镰孢对多菌灵的抗性与咪鲜胺、戊唑醇、三唑酮及吡唑醚菌酯之间均不存在交互抗性关系。     

芒果炭疽病菌对多菌灵的抗药性

对来自广东和海南等不同果园的芒果炭疽病菌进行了对多菌灵的抗性测定.结果表明,敏感菌株的最小抑制浓度(MIC)为0.110μg/mL,而抗性菌株在多菌灵500μg/mL下仍生长良好.抗性菌株经继代培养10代后抗性几乎不变,说明其抗性稳定.对抗、感菌株的生物学特性进行测定,然后以产孢量和致病力分别用MIC做简单相关性分析,证明病菌的生物学特性、产孢量、致病力与抗药性无关,因此可以认为病菌对多菌灵的抗药性突变并不影响其正常的生理功能.抗性菌株对甲基硫菌灵、苯菌灵、噻菌灵表现正交互抗性,而对乙霉威和咪鲜胺敏感.病菌在含药培养基上测定的敏感性与在经多菌灵处理过的离体果实上的敏感性有较好的对应关系,可用于大田抗药性的初步检测.     

抗啶酰菌胺蔬菜灰霉病菌突变体的诱导及其生物学性状

为评价蔬菜灰霉病菌对啶酰菌胺的抗性风险,采用紫外线照射和药剂驯化相结合的诱导方法,对蔬菜灰霉病菌D9、L17、J9亲本敏感菌株进行了室内啶酰菌胺抗性诱导,并采用菌落直径法比较了抗、感菌株在生物学性状方面的差异。结果显示,共获得不同抗性水平的突变体23株,其中突变体D9-4的抗性倍数为253.76倍,达高抗水平。突变体菌丝生长速率较敏感菌株有所下降,抗、感菌株的适宜生长温度均为25 ℃,敏感菌株最适pH为5,突变体最适pH为7,突变体适应酸碱度和温度变化的能力较敏感菌株差;低抗突变体产孢量和孢子萌发率与敏感菌株无显著差异,但高抗突变体产孢量和孢子萌发率较敏感菌株显著降低;在无药条件下,敏感菌株致病力强于抗性突变体,而在药剂胁迫下,突变体表现出一定的耐药性,致病力强于敏感菌株;6株突变体无药继代培养15代后,突变体抗性稳定遗传。此外,蔬菜灰霉病菌对啶酰菌胺与其它5种杀菌剂之间没有交互抗性。研究表明,蔬菜灰霉病菌抗啶酰菌胺突变体适合度较低,但在药剂选择压力下容易形成啶酰菌胺抗性群体,在生产中需引起注意。     

绿僵菌Ma55抗多菌灵突变株的诱变及抑菌作用研究

在室内条件下测定了供试绿僵菌对多菌灵的抗性。结果表明, 供试菌株对多菌灵均表现为敏感, 其中, Ma55菌株对多菌灵最敏感。采用分生孢子定向筛选的方法获得了金龟子绿僵菌抗多菌灵突变株, 测定了抗性突变株对多菌灵的抗性差异。结果显示, 在获得的抗性突变株中, MC-2的EC50最大, 达到397.064 3μg/mL, 对多菌灵的抗性水平最高, 抗性水平指数达到102.35。对Ma55抗多菌灵突变株的菌丝生长速率、产孢量及对棉花枯萎病菌和棉花红腐病菌的抑制效果的研究结果表明, 抗性突变株的菌丝生长速率均比亲本菌株Ma55小, 但产孢量均比Ma55大, 其中, MC-2的产孢量最大, 为5.12×106个/mL; MC-5次之, 其产孢量为4.81×106个/mL, MC-8的产孢量在抗性突变株中最低。平板对峙培养结果显示, 金龟子绿僵菌抗多菌灵突变株对棉花枯萎病菌和棉花红腐病菌菌丝生长的抑制作用均达到显著水平, 其中, MC-2对棉花枯萎病菌、棉花红腐病菌菌丝生长的抑制作用最强, 与亲本对照菌株Ma55差异不显著。     

抗氰烯菌酯假禾谷镰孢突变体的诱导及其生物学特性

为评估引起小麦茎基腐病的病原菌假禾谷镰孢Fusarium pseudograminearum对氰烯菌酯的抗性风险,对5株敏感菌株进行了室内药剂驯化,获得33株抗性突变体,突变频率为16.5%,其对氰烯菌酯的抗性水平范围为7.39～1 665.76倍,3株表现低抗,4株表现中抗,26株表现高抗;发现在myosin-5基因上存在11种抗性突变类型,其中217位的丝氨酸突变为亮氨酸(S217L)、420位的谷氨酸突变为赖氨酸(E420K)和135位的丙氨酸突变为苏氨酸(A135T)为主要突变类型,其比例分别为45.5%、15.2%和9.1%。S217L型抗性突变体的产孢量显著下降,菌丝生长速率和致病力与亲本菌株无显著差异。E420K型抗性突变体的菌丝生长速率和致病力显著下降,产孢量与亲本菌株无显著差异。A135T型抗性突变体的菌丝生长速率和产孢量与亲本菌株无显著差异。研究结果表明假禾谷镰孢在药剂选择压力下易形成氰烯菌酯的抗性群体,对氰烯菌酯存在中到高等的潜在抗性风险,其myosin-5的点突变与其对氰烯菌酯的抗性相关。     

大豆胶孢炭疽菌对苯醚甲环唑的抗性机制及其抗性突变体的适合度

为明确大豆胶孢炭疽菌Colletotrichum gloeosporioides对苯醚甲环唑的抗性风险及其抗性机制,采用药剂驯化法诱导获得其抗性突变体,并测定抗性突变体的适合度和交互抗性,同时分析抗性突变体和敏感菌株cyp51A和cyp51B基因的cDNA序列、启动区序列及相对表达量。结果表明:从大豆胶孢炭疽菌2株敏感菌株中筛选获得7株低抗苯醚甲环唑的突变体,突变频率为1.75×10^-4,其抗药性可以稳定遗传。抗性突变体与亲本敏感菌株在对温度的敏感性、菌丝生长速率、产孢量和致病力方面均存在一定差异。苯醚甲环唑与丙环唑之间存在中等交互抗性(相关系数为0.80,P<0.05),苯醚甲环唑与咪鲜胺锰盐、多菌灵、氟啶胺和吡唑醚菌酯之间无交互抗性。抗性突变体cyp51A和cyp51B基因的cDNA序列未发生核苷酸突变,cyp51A和cyp51B基因的启动区无插入片段。经苯醚甲环唑处理后,4株抗性突变体lq27-7-1、lq27-7-2、lq30-2-1和lq30-2-2的cyp51A基因相对表达量被诱导上调倍数显著高于亲本敏感菌株;3株抗性突变体lq27-7-2、lq...     

抗氟吡菌胺辣椒疫霉菌株的诱导及其生物学特性的研究

 采用菌丝生长速率法, 测定了采自泰安、平谷、杭州和昆明4个地区的42株辣椒疫霉病菌对氟吡菌胺的敏感性, 结果表明, 其EC₅₀值在0.618 ~0.927 μg·mL^-1之间, 平均EC₅₀ =(0.743±0.067 7) μg·mL^-1。 42个菌株对氟吡菌胺的敏感性分布呈单峰曲线, 未出现抗性的病原菌亚群体, 可将其单峰曲线作为辣椒疫霉对氟吡菌胺的敏感性基线。采用药剂驯化和紫外照射对辣椒疫霉敏感菌株TA进行诱变处理, 获得了2株辣椒疫霉抗氟吡菌胺菌株;利用菌落直径法测定抗氟吡菌胺菌株的遗传稳定性、菌丝生长速率及对其它杀菌剂的交互抗性;通过活体叶盘法测定抗氟吡菌胺菌株和敏感菌株的致病力及产孢子囊能力, 分析抗性和敏感菌株之间生物学特性差异。结果表明, 敏感菌株TA经过氟吡菌胺 48代连续汰选, 其抗性达58.0倍, 获得中抗菌株TA-R;紫外照射获得了抗性达260.6倍的高抗菌株TA-UV, 且其抗性均能稳定遗传;TA-R和TA-UV对甲霜灵、霜脲氰表现出正交互抗性, 对烯酰吗啉、百菌清、代森锰锌和丙森锌无交互抗性;抗氟吡菌胺菌株TA-R、TA-UV与敏感菌株在活体叶盘上的致病力、离体产孢能力均差异不显著(P＜0.05), 但其菌丝生长速率、菌丝干重均低于敏感菌株。     

高温胁迫对禾谷镰孢生长和致病力的影响

为探究高温胁迫对禾谷镰孢生长和致病力的影响, 本研究测定了禾谷镰孢5株耐高温菌株和4株温度敏感型菌株在25℃和30℃下的菌丝生长速率、产孢量、孢子萌发率以及不同胁迫压力下的生长速率、致病力和DON毒素含量等。结果表明, 不论耐高温菌株还是温度敏感型菌株, 30℃高温对其菌丝生长均有抑制作用, 但对产孢量和孢子萌发有促进作用;30℃高温能减轻NaCl和CaCl2胁迫对禾谷镰孢生长的抑制, 但是不影响KCl、刚果红, SDS和H2O2对病原菌的抑制作用;在30℃下, 大部分耐高温菌株的致病力不变或降低, 而大部分温度敏感型菌株的致病力反而增加, 30℃对大部分菌株的DON毒素产量有一定促进作用。研究结果可为研究气候变化下小麦赤霉病的流行和预测提供理论基础。     

水稻恶苗病菌田间抗咪鲜胺菌株的适合度及其交互抗性

恶苗病是水稻生产上较为严重的种传真菌病害,咪唑类广谱内吸性杀菌剂咪鲜胺是目前防治该病害的主要药剂。以对咪鲜胺抗性及敏感的田间水稻恶苗病菌为试材,研究了其适合度及对几种常用杀菌剂的交互抗性。结果显示:抗性菌株的抗药性可稳定遗传,其温度敏感性与敏感菌株无明显差异,部分抗性菌株在菌丝生长速率、产孢量、孢子萌发率和致病力方面显著高于田间敏感菌株;咪鲜胺与三唑类及2-氰基丙烯酸酯类杀菌剂之间均无交互抗性。研究表明,对咪鲜胺产生抗性的水稻恶苗病菌具有较强的适合度,在田间自然条件下有可能形成优势群体,因此需合理轮换使用不同作用机制的杀菌剂,以延缓其抗药性的发展。     

Vegetative compatibility grouping in Botrytis cinerea using sulphate non-utilizing mutants

Twenty-one strains of Botrytis cinerea isolated from six plant species on ten sites throughout Israel, as well as a strain from France, were tested for vegetative and mycelial incompatibility, pathogenicity, resistance to the fungicides carbendazim and iprodione, and colony morphology. Selenate-resistant mutants were isolated from the strains as spontaneous, fast-growing sectors arising from restricted colonies on medium amended with sodium selenate with a mean frequency of 0.04 sectors/colony; 81% of the sectors were sulphate non-utilizing (sul) mutants. One hundred and four sul mutants were divided into two complementary groups: resistant (66 mutants) and sensitive to chromate. Based on compatibility reactions between chromate-resistant and chromate-sensitive sul mutants, 12 strains were compatible only with themselves and were each classified as belonging to different vegetative compatibility groups (VCGs). Nine strains were each compatible with one to three other strains, and were assembled into three multi-member VCGs. Mycelial incompatibility between wild-type strains (barrage), in the form of a zone of dark pigmentation or sparse mycelium with or without dark pigmentation of the agar along the line of confrontation, was observed for 70% of the inter-strain pairings. There was no correspondence in compatibility between strains revealed by two approaches: strains in different VCGs did not necessarily produce a barrage. However, self-compatibility was observed both as heterokaryon formation between complementary sul mutants and as an absence of barrages between mycelia of wild-type strains; wild-type strains belonging to the same VCG did not exhibit strong barrages, although weak antagonistic reactions were observed. Strains in two multi-member VCGs showed the same patterns of resistance to carbendazim and iprodione; the third multi-member VCG contained isolates with different patterns of resistance. Four morphological types were revealed among wild-type strains: conidial (five strains), sclerotial (six strains), intermediate (ten strains), and mycelial (one strain). On bean leaves, conidial strains were more aggressive than sclerotial strains.     

Effect of Phenylpyrrole-resistance Mutations on Ecological Fitness of <Emphasis Type="Italic">Botrytis cinerea</Emphasis> and their Genetical Basis in <Emphasis Type="Italic">Ustilago maydis</Emphasis>

Mutants of Botrytis cinerea and Ustilago maydis highly resistant to fludioxonil were isolated at a high frequency, after nitrosoguanidine or UV mutagenesis, respectively, and selection on media containing fludioxonil. Tests on the response of mutant strains to high osmotic pressure resulted in the identification of two fludioxonil-resistant phenotypes (FLD_osm/s and FLD_osm/r), regarding the sensitivity to high osmolarity. Approximately 95% of fludioxonil-resistant mutants were found to be more sensitive to high osmotic pressure than the wild-type parent strains. Genetic analysis of phenylpyrrole-resistance in the phytopathogenic basidiomycete U. maydis, showed that fludioxonil-resistance was coded by three unlinked chromosomal loci (U/fld-1, U/fld-2 and U/fld-3), from which only the U/fld-1 mutation coded an osmotic sensitivity similar to that of the wild-types. Cross-resistance studies with fungicides from other chemical groups showed that the mutations for resistance to phenylpyrroles affect the sensitivity of mutant strains to the aromatic hydrocarbon and dicarboximide fungicides, but not to the benzimidazoles, anilinopyrimidines, phenylpyridinamines, hydroxyanilides or the sterol biosynthesis inhibiting fungicides. A study of fitness parameters in the wild-type and fludioxonil-resistant mutants of B. cinerea, showed that all osmotic sensitive (B/FLD_osm/s) isolates had significant reductions in the characteristics determining saprophytic fitness such as mycelial growth, sporulation, conidial germination and sclerotial production. Contrary to that, with the exception of mycelial growth, the fitness parameters were unaffected or only slightly affected in most of the osmotic resistant (B/FLD_osm/r) isolates. Tests on cucumber seedlings showed that the osmotic-sensitive strains were significantly less pathogenic compared with the wild-type and B/FLD_osm/r strains of B. cinerea. Preventative applications of the commercial products Saphire 50 WP (fludioxonil) and Rovral 50 WP (iprodione) were effective against lesion development on cotyledons by the wild-type and the mutant strains of B. cinerea that were resistant to the anilinopyrimidine cyprodinil (B/CPL-27) and to the hydroxyanilide fenhexamid (B/FNH-21), but ineffective, even at high concentrations, against disease caused by the fludioxonil-resistant isolates (B/FLD) and a mutant strain resistant to the dicarboximide iprodione (B/IPR-1). Experiments on the stability of the fludioxonil-resistant phenotype showed a reduction of resistance, mainly in osmotic-sensitive isolates, when the mutants were grown on inhibitor-free medium. A rapid recovery of the high resistance was observed after mutants were returned to the selection medium. Studies on the competitive ability of mutant isolates against the wild-type parent strain of B. cinerea, by applications of a mixed conidial population, showed that, in vitro, all mutants were less competitive than the wild-type strain. However, the competitive ability of osmotic-resistant mutants was higher than the osmotic-sensitive ones. Furthermore, competition tests, in planta, showed a significant reduction of the frequency of both phenylpyrrole-resistant phenotypes, with a respective increase in the population of the wild-type strain of the pathogen.     

Morphological and physiological characteristics of dicarboximide-sensitive and resistant isolates of Botrytis cinerea1

Various morphological and physiological characteristics, such as mycelial colour and appearance, mycelial growth rates, sporulation, pathogenicity on different hosts, activity of cell-wall degrading enzymes, competitive ability and osmotic sensitivity of five dicarboximide-resistant isolates of Botrytis cinerea were compared to those of their sensitive parent strains. There were only small reductions in mycelial growth rates of resistant strains as compared to the sensitive ones, whereas all of them showed greatly reduced rates of sporulation. With only one exception, the pathogenicity of the resistant isolates was reduced by varying extents compared with the sensitive parent strains. While the proteolytic activity of resistant strains tended to be higher, the activities of peclolytic enzymes were often lower than those of the sensitive isolates. In competition tests, resistant conidia often completely disappeared after a few passages on untreated plants. In only one of the resistant isolates tested so far was dicarboximide resistance related to a high osmotic sensitivity.     

灰葡萄孢多药抗性菌株的筛选和鉴定

从浙江杭州市售草莓上分离得到83个灰葡萄孢菌株,测定了这些菌株对苯醚菌酯、多菌灵和异菌脲的敏感性,筛选出对这3种药剂同时产生了抗性的两个菌株HZ021和HZ054,其在马铃薯葡萄糖琼脂(PDA)平板上的菌丝生长和产孢量与敏感菌株相比无显著差异,在黄瓜叶片上均表现出很强的致病力。结果表明,HZ021和HZ 054有很高的适合度。通过对抗性菌株中细胞色素b (CYT b)、双组份组氨酸激酶(OS-1)和β-微管蛋白(TUB 2)基因序列进行分析发现,HZ021和HZ054对多种药剂的抗性是由于其药剂靶标基因上的点突变所致。     

Sexual recombination of carbendazim resistance in Fusarium graminearum under field conditions

BACKGROUND: Carbendazim has been the major fungicide for control of Fusarium head blight (FHB) caused by Fusarium graminearum Schwade in China. However, the effectiveness of carbendazim has been threatened by the emergence of resistant pathogen populations in the field. RESULTS: Five isolates, representing three phenotypes of different carbendazim sensitivity levels (S, MR and HR), were randomly selected to study the inheritance of carbendazim resistance by three genetic crosses under field conditions. Each parent in all crosses was marked with a different class of nitrate non‐utilizing (nit) mutation. The presence of sexual recombinants indicated that outcrossing had occurred in the crosses. Over 100 putative self‐crossing or outcrossing perithecia for each cross were randomly sampled on the surface of the haulms of dead rice for each pair of parents. Results showed that 5.7–20.9% outcrossing frequency occurred in the three crosses and confirmed sexual recombination under field conditions. There were no significant differences in mycelial linear growth and pathogenicity between the selected recombinants and their parents, but they differed in sporulation ability and capacity to produce perithecia. Nevertheless, most of the sexual recombinants possessed fitness levels comparable with those of their parents. CONCLUSION: Outcrossing between carbendazim‐sensitive and ‐resistant isolates did occur under field conditions, and sexual recombination must play a role in the development of carbendazim resistance in the field. Copyright © 2009 Society of Chemical Industry     

Identification of a novel point mutation in the <Emphasis Type="Italic">β</Emphasis>-tubulin gene of <Emphasis Type="Italic">Botrytis cinerea</Emphasis> and detection of benzimidazole resistance by a diagnostic PCR-RFLP assay

The molecular basis of resistance to benzimidazole fungicides with laboratory and field mutant isolates of Botrytis cinerea was investigated. After chemical mutagenesis with N-methyl-N-nitrosogouanidine (NMNG) two different benzimidazole-resistant phenotypes were isolated on media containing carbendazim or a mixture of carbendazim and diethofencarb. The mutant isolates from the fungicide-mixture-containing medium were moderately resistant to carbendazim with wild-type tolerance to diethofencarb while mutant isolates from carbendazim-containing medium were highly resistant to carbendazim but sensitive to diethofencarb. The studied field isolates were highly resistant to benzimidazoles and sensitive to diethofencarb. Study of fitness characteristics of benzimidazole highly-resistant isolates showed that the resistance mutation(s) had no apparent effect on fitness-determining parameters. Contrary to this, the moderately benzimidazole-resistant strains, with no increased diethofencarb sensitivity, had a significant reduction in certain ecological fitness-determining characteristics. Analysis of the sequence of the β-tubulin gene revealed two amino acid replacements in the highly benzimidazole-resistant mutants compared to that of the wild-type parent strain. One was the glutamic acid (GAG) to alanine (GCG) change at position 198 (E198A), identified in both laboratory and field highly benzimidazole-resistant isolates, a mutation previously implicated in benzimidazole resistance. The second was a novel benzimidazole resistance mutation of glutamic acid (GAG) to glycine (GGG) substitution at the same position 198 (E198G), identified in a highly benzimidazole-resistant laboratory mutant strain. Molecular analysis of the moderately benzimidazole-resistant strains revealed no mutations at the β-tubulin gene. A novel diagnostic PCR-RFLP assay utilising a BsaI restriction site present in the benzimidazole-sensitive (E198) but absent in both resistant genotypes (E198G and E198A) was developed for the detection of both amino acid replacements at the β-tubulin gene.     

番茄灰霉病菌对咯菌腈的抗性诱变及抗药突变体的生物学特性

为评估番茄灰霉病菌Botrytis cinerea对咯菌腈的抗性风险,就室内经紫外照射获得抗药突变体的方法及抗性突变体的生物学性状进行了研究。结果表明:番茄灰霉病菌分生孢子的紫外照射亚致死时间为90~120 s;经亚致死时间紫外照射后,4个亲本菌株中有2个菌株共产生了6个抗咯菌腈的突变体,其EC50值是亲本菌株的310倍以上,抗性突变频率为3.13×10-7;经紫外照射诱变获得的所有抗性突变体在菌丝生长速率、产孢量、产菌核能力及其在番茄果实上的致病性方面均比其亲本菌株明显降低。相关分析显示,所得抗咯菌腈突变体对氟啶胺、啶菌唑、啶酰菌胺和嘧霉胺无交互抗性。表明番茄灰霉病菌对咯菌腈的抗药性风险较低。     

西瓜蔓枯病菌啶酰菌胺抗性突变体的生物学特性研究及其Sdh B基因位点检测

为评价西瓜蔓枯病菌对啶酰菌胺的抗性风险,了解其抗性机理,室内通过药剂驯化方法获得2株啶酰菌胺的抗性突变体XF21-3和YC60-1,测定了抗性突变体的生物学特性,并通过对Sdh B基因片段的测序比对,分析了西瓜蔓枯病菌对啶酰菌胺的抗性机理。生物测定结果表明:啶酰菌胺对2株抗性突变体的EC50值分别为108和124 μg/mL,抗性倍数（RR）分别为1 007和1 347,均为高抗菌株;抗性突变体的菌丝生长速率和产孢量均大于亲本菌株,但其致病性与亲本菌株无显著差异,对外界环境渗透压的敏感性低于亲本菌株;此外,啶酰菌胺与萎锈灵、戊唑醇、乙霉威及醚菌酯之间均不存在交互抗性,但与噻呋酰胺之间存在交互抗性。Sdh B基因片段测序及比对结果表明,高抗性突变体中Sdh B亚基277位上的氨基酸所对应的碱基由CAC突变为TAC,即由组氨酸（His）突变为酪氨酸（Tyr）。研究表明,西瓜蔓枯病菌在药剂选择压力下容易形成啶酰菌胺的抗性群体,且抗性突变体的离体适合度高于亲本菌株,此外,啶酰菌胺与同类型杀菌剂噻呋酰胺之间存在交互抗性,因此认为西瓜蔓枯病菌对啶酰菌胺具有中等抗性风险;同时进一步验证了Sdh B亚基277位上的氨基酸突变（His→Tyr,CAC→TAC）是西瓜蔓枯病菌对啶酰菌胺产生抗性的原因。