First application of PCR-Luminex system for molecular diagnosis of fungicide resistance and species identification of fungal pathogens

Fungicide resistance in plant pathogens is often caused by a single point mutation in a gene encoding fungicide target proteins. Such is the case for resistance to MBI-D (inhibitors of scytalone dehydratase in melanin biosynthesis) fungicides in rice blast fungus (Magnaporthe oryzae), which is caused by a mutation in the scytalone dehydratase gene that results in a replacement of valine with methionine at codon 75 of the fungicide target protein. PCR-Luminex, a novel system developed for high-throughput analysis of single nucleotide polymorphisms (SNPs) was successfully introduced to diagnose MBI-D resistance using specific oligonucleotide probes coupled with fluorescent beads. The PCR-Luminex system was further tested for its potential in identifying species causing Fusarium head blight on wheat. Four major pathogens, Fusarium graminearum (=F. asiaticum), F. culmorum, F. avenaceum, and Microdochium nivale, known to cause the disease, were tested, and the species were identified using the PCR-Luminex method. So far, this report is the first on the application of the DNA-based PCR-Luminex system in the area of crop protection and/or agricultural sciences.     

不同药剂对绿豆轮纹病菌的室内毒力测定

对16种化学药剂和5种生物药剂进行了室内毒力测定,筛选出3种抑制病菌菌丝生长效果 较好的药剂：世高、施保克和多菌灵。世高的有效中浓度最小(EC50=40． 04) ,其抑制菌丝生长的 效果是最好的,其次是多菌灵(EC50=67． 76) ,最后是施保克(EC50=95． 50) 。方差分析结果表 明,3种药剂在不同时间、不同浓度下的抑菌效果明显,5种生物药剂的抑菌效果较差。     

6种杀菌剂对马铃薯枯萎病菌的室内毒力测定

选择75%百菌清可湿性粉剂(WP)、36%甲霜灵锰锌悬浮剂(SC)、70%恶霉灵可湿性粉剂(WP)、50%甲基硫菌灵可湿性粉剂(WP)、6%春雷霉素可湿性粉剂(WP)、22.5%抑霉唑乳油(EC)6种杀菌剂对3种马铃薯枯萎病病原菌进行室内毒力测定。结果表明:6种药剂对病原菌菌丝生长的抑制效果差异很大,50%甲基硫菌灵(WP)和22.5%抑霉唑(EC)对3种病原菌的抑菌效果均很好,EC50分别为1.69、5.59、5.03μg/mL和3.60、5.17、1.58μg/mL。     

豇豆轮纹病病原鉴定及其室内药剂筛选

从海南三亚豇豆设施棚内采集具典型轮纹病病斑的豇豆叶片,采用组织分离法分离到1株致病菌,根据病害症状特点、病原菌形态特征、培养性状、ITS序列分析,鉴定豇豆轮纹病的病原菌为多主棒孢霉[Corynespora cassiicola (Berk. & Curst.) Wei];利用生长速率法,对12种药剂进行室内筛选,结果表明：10%苯醚甲环唑(WP,可湿性粉剂)和50%异菌脲(WP)对病原菌具有强烈抑制作用,其EC50分别为2.709 46和9.093 27 mg/L,而75%百菌清(WP)和50%多菌灵(W     

块茎类植物酯酶对有机磷农药残留的检测

采用酶抑制法,选用五种块茎土豆、红薯、茨菇、芋头、莲藕提取植物酯酶,测定了总酯酶活力和比活力大小,结果显示土豆、茨菇、莲藕的酯酶活力分别高达8.462 3、8.743 7、7.491 0,显著高于其他几种。探索其检测有机磷农药的最佳条件,对5种有机磷农药进行了敏感性试验,并测定3种植物酯酶对这5种有机磷农药的最低检测限(LOD)。3种植物酯酶对受试的5种有机磷农药均有良好的敏感性,且最低检测限远低于国家规定的最大残留限量(MRL)。因此,这几种酶可作为有机磷农药残留检测用酶。     

5种药剂对2株立枯丝核菌的室内毒力测定

采用生长速率法,在室内测定了w=25%丙环唑、w=12.5%戊唑醇、w=80%乙蒜素、w=25%咪鲜胺和w=5%井冈霉素5种杀菌剂对R-HKB和R-DZC两株立枯丝核菌(Rhizoctonia solani)的毒力。结果表明:丙环唑对R-HKB的毒力和戊唑醇对R-DZC的毒力均最大,其EC50值分别为0.0132mg·L-1和0.4131mg·L-1;井冈霉素对R-HKB和R-DZC的毒力均最小,其EC50值分别为714.4948mg·L-1和663.4171mg·L-1。其毒力倍数分别比丙环唑和戊唑醇小(54128.4倍和1606.0倍)。提示:丙环唑和戊唑醇对R-HKB和R-DZC两株立枯丝核菌有很好的抑制效果。     

Fungal disease suppression by inorganic salts: A review

This paper reviews the scientific literature on the topic of fungal disease suppression by applications of inorganic salts as alternatives to synthetic fungicides on a global scale for both protected and field crops. Where data were available, the comparative efficacy of inorganic salts with conventional fungicide products is discussed. In total, published evidence was found for 34 inorganic salts (mainly bicarbonates, phosphates, silicates, chlorides and phosphites) that were able to reduce the severity of 49 fungal diseases (of the foliage, stem, fruit, tuber, root and post-harvest) in 35 plant species (vegetables, cereals, fruit crops, root/tuber crops, ornamentals and native plants). The most studied and best controlled disease with inorganic salts was powdery mildew of cucurbits [Sphaerotheca fuliginea (Schltdl.) Pollacci 1913 or Erysiphe cichoracearum DC. 1805; up to 99% efficacy], wheat [Blumeria graminis (DC.) Speer 1975 (f. sp. tritici)] and grapes [Uncinula necator (Schwein.) Burrill 1892]. The next best evidence for disease control was for wheat septoria blotch (Septoria tritici Berk. & M.A. Curtis 1874), rice blast [Magnaporthe grisea (T.T. Hebert) M.E. Barr 1977], potato late blight [Phytophthora infestans (Mont.) de Bary 1876] and several other Phytophthora spp. The published evidence suggests that these 34 inorganic salts are generally less effective than conventional fungicides and could not fully replace them. However, their integration in a disease management strategy may enable a reduction in the number of conventional fungicide applications required. The potential for the inclusion of inorganic salts in fungal disease management programmes merits further investigation and greater regulatory innovation in the near future.     

木薯新叶斑病病原鉴定及其生物学特性

2008和2009年在对木薯主产区病害的普查中,发现了一种新的叶斑病,命名为离孺孢叶斑病。形态观察结果表明,该病原菌分生孢子梗丛生,褐色,基细胞膨大呈半球形,成熟的分生孢子长椭圆形,两端钝圆,具5～8个隔膜,表明其为狗尾草离孺孢。ITS序列分析结果表明其和一株狗尾草离孺孢(EF452444)的序列同源性为99%。生物学特性研究结果表明,PDA培养基、28℃、pH7和光暗交替是菌落生长最适条件,D-葡萄糖和硝酸钠是其最适碳氮源,孢子萌发最适温度和致死温度分别为28℃和55℃5min。10种杀菌剂的室内筛选结果表明,咪鲜胺(25%咪鲜胺EC)的EC50值最小,抑菌效果最好。     

A single amino acid substitution in the SdhB protein of succinate dehydrogenase determines resistance to amicarthiazol in Xanthomonas oryzae pv. oryzae

BACKGROUND: Xanthomonas oryzae pv. Oryzae Ishiyama, a causal agent of rice bacterial leaf blight, was found to be sensitive in vitro to the systemic fungicide amicarthiazol (2‐amino‐4‐methylthiazole ‐5‐carboxanilide), which is a potent inhibitor of succinate dehydrogenase (SDH, EC 1.3.99.1). This paper aimed to determine the molecular resistance mechanism of X. oryzae pv. oryzae to amicarthiazol. RESULTS: UV‐induced resistant mutants of X. oryzae pv. oryzae to amicarthiazol were isolated. The activity of SDH in wild‐type X. oryzae pv. oryzae was strongly inhibited by amicarthiazol, while that in resistant mutants was insensitive, although their SDH activity was decreased compared with the wild‐type sensitive strain without amicarthiazol. A mutation of Histidine₂₂₉ (CAC) to Tyrosine₂₂₉ (TAC) was identified in sdhB, which encoded the iron–sulfur protein subunit of SDH. The sdhB from the mutant was ligated into a cosmid, pUFR034, to generate pUFR034RAX, which conferred resistance to amicarthiazol when transformed into the wild‐type sensitive strain. CONCLUSION: A mutation of His₂₂₉ (CAC) to Tyr₂₂₉ (TAC) in SdhB was responsible for determining amicarthiazol resistance. Copyright © 2010 Society of Chemical Industry     

新型植物源农药0.5%大黄素甲醚水剂对黄瓜白粉病菌的毒力测定及田间药效

0.5%大黄素甲醚水剂是湖北省农科院植保土肥所和内蒙古清源保生物科技有限公司联合创制的一种新颖的植物源杀菌剂,其化学结构式为1,8-二羟基-3-甲氧基-6-甲基蒽醌。室内孢子萌发抑制试验结果表明,大黄素甲醚对黄瓜白粉病菌孢子萌发的抑制中浓度EC50为0.37μg/mL;田间药效试验结果表明,0.5%大黄素甲醚水剂对黄瓜白粉病菌具有良好的保护和防治效果,有效成分用量18~45 g/hm2的防治效果明显高于15%三唑酮可湿性粉剂135 g/hm2的防效。