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991.
将指形管装的粟锈菌夏孢子和纸袋装的病叶保存在冰箱中,10个月后夏孢子仍有一定的发芽率,用其接种谷子可引起发病。随着保存时间的推移,夏孢子的发芽率及其接种发病程度也降低。寄主范围试验表明,该菌可侵染狗尾草属中的几种狗尾草,但不侵染金色狗尾草。 相似文献
992.
Peter G. Markham Ian D. Bedford Sijun Liu Marion S. Pinner 《Pest management science》1994,42(2):123-128
The cosmopolitan whitefly species, Bemisia tabaci (Gennadius) and Trialeurodes taporariorum (Westwood) have always been regarded as pests to a large range of worldwide crops. Both species are capable of transmitting plant viruses, with T. vaporariorum being the vector of only a few ‘clostero’-like viruses and B. tabaci the vector of viruses in several groups. The largest group of viruses transmitted by B. tabaci are the geminiviruses and B. tabaci is known to transmit around 60 members. Until recently, B. tabaci had been associated with only a limited range of host plants within any one region, although its total potential host range was large. Virus transmission was confined within the plant host range of each regional population of B. tabaci. The emergence of the polyphagous ‘B’ biotype of B. tabaci with its increased host range of more than 600 plant species, has resulted in geminiviruses infecting previously unaffected crops. As the ‘B’ biotype spreads further into Europe, European field and glasshouse crops have been shown to be susceptible to whitefly-transmitted viruses already endemic to other parts of the world. More than 20 colonies of B. tabaci, including both ‘B’ and non-‘B’ biotypes from disparate global locations have been compared for their ability to transmit more than 20 geminiviruses. All but two highly host-specific colonies were capable of transmitting most geminiviruses tested. However, some viruses were transmitted more efficiently than others. The virus coat protein or capsid is essential for vector recognition and transmission. By comparing transmissible viruses at the molecular level to viruses that are no longer whitefly-transmissible, the active epitope on the virus coat protein could be identified for designing future virus control strategies. 相似文献
993.
紫外光诱导灰葡萄孢产生抗多菌灵菌株的研究 总被引:10,自引:1,他引:10
测得多菌灵对Botrytis cinerea野生菌株B_2的最低抑制生长浓度(MIC)值为0.5ppm。然而,经紫外光照射定向诱导,从B_2获得了突变频率为I/0.9—4.5×10~4的抗多菌灵突变菌株。这种抗性菌株在含多菌灵1000ppm的马铃薯蔗糖琼脂培养基上,菌丝生长很少受到抑制,在多菌灵2000ppm情况下仍能生长,难以测定MIC值。诱变抗性菌株(B-UV1)在无药培养基上连续培养8个月,抗性程度仍未下降,但生长速率降低。 B-UV1菌株对苯来持、托布津杀菌剂表现高度的交互抗性,但对克菌丹等4种测试药剂的敏感性,与野生菌株相似。接种草莓时,B-UV1菌株引起的发病率为野生菌株的77.8%,而且病情较轻。 相似文献
994.
Shelton GD Liu LA Guo LT Smith GK Christiansen JS Thomas WB Smith MO Kline KL March PA Flegel T Engvall E 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2001,15(3):240-244
The most common form of muscular dystrophy in dogs and humans is caused by mutations in the dystrophin gene. The dystrophin gene is located on the X chromosome, and, therefore, disease-causing mutations in dystrophin occur most often in males. Therefore, females with dystrophin deficiency or other forms of muscular dystrophy may be undiagnosed or misdiagnosed. Immunohistochemistry was used to analyze dystrophin and a number of other muscle proteins associated with muscular dystrophy in humans, including sarcoglycans and laminin alpha2, in muscle biopsy specimens from 5 female dogs with pathologic changes consistent with muscular dystrophy. The female dogs were presented with a variety of clinical signs including generalized weakness, muscle wasting, tremors, exercise intolerance, gait abnormalities, and limb deformity. Serum creatine kinase activity was variably high. One dog had no detectable dystrophin in the muscle; another was mosaic, with some fibers normal and others partly dystrophin-deficient. A 3rd dog had normal dystrophin but no detectable laminin alpha2. Two dogs could not be classified. This study demonstrates the occurrence of dystrophin- and laminin alpha2-associated muscular dystrophy and the difficulty in clinical diagnosis of these disorders in female dogs. 相似文献
995.
Obermeier C Sears JL Liu HY Schlueter KO Ryder EJ Duffus JE Koike ST Wisler GC 《Phytopathology》2001,91(8):797-806
A soilborne disease of lettuce, associated with necrosis and dieback, has been found with increasing frequency in California and Arizona over the last 10 years. An isometric virus, serologically related to Tomato bushy stunt virus (TBSV), was consistently isolated from lettuce plants with these disease symptoms. Back-inoculation to healthy lettuce plants and subsequent reisolation of the virus from symptomatic lettuce leaves suggested that this virus was the causal agent of this disease. A tombusvirus was also associated with a necrosis disease of greenhouse-grown tomatoes in Colorado and New Mexico. Complementary DNA representing the 3' end of viral genomic RNAs recovered from diseased lettuce and tomato plants had identical nucleotide sequences. However, these sequences were divergent (12.2 to 17.1%) from sequences of the previously described strains of TBSV, Petunia asteroid mosaic virus (PAMV), Artichoke mottled crinkle virus, and Carnation Italian ringspot virus. Additional tombusvirus isolates were recovered from diseased lettuce and tomato plants and these were most closely related to the TBSV-cherry strain (synonymous with PAMV) and to Cucumber necrosis virus based on comparison of 3'-end sequences (0.1 to 0.6% and 4.8 to 5.1% divergence, respectively). Western blot analysis revealed that the new tombusvirus isolated from diseased lettuce and tomato plants in the western United States is serologically distinct from previously described tombusvirus species and strains. Based on genomic and serological properties, we propose to classify this virus as a new tombusvirus species and name it Lettuce necrotic stunt virus. 相似文献
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999.
侵染观赏南瓜的黄瓜绿斑驳花叶病毒的初步鉴定 总被引:26,自引:2,他引:26
从广西某农业展示中心观赏南瓜上分离到一种直杆状病毒,长约300nm,该病毒分离物P-3(NN)在测试的葫芦科作物上表现为系统花叶、褪绿斑及明脉症状,在曼陀罗上为局部褪绿斑,在测试的其它茄科作物及豆科和藜科作物上无任何症状反应.其致死温度为95~100℃.经DAC-ELISA测定,P-3(NN)与黄瓜绿斑驳花叶病毒有密切的血清学关系.根据以上结果,初步鉴定P-3(NN)为黄瓜绿斑驳花叶病毒(CGMMV)的一个分离物. 相似文献
1000.
对广东省鹤山和东莞莲花山自然保护区的小蛾类昆虫进行调查,计有8科35属43种。其中广东新记录种14种。 相似文献