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991.
Teruo NONOMURA Yoshinori MATSUDA Mikako TAKASUGI Takashi OOTANI Tomoya HASEGAWA Kazutomo MIYAJIMA Tetsuya HATASA Hideyoshi TOYODA 《Journal of General Plant Pathology》2001,67(4):273-280
Using melon seedlings at the cotyledon stage and genetically marked fungi, a system for monitoring pathogenic and nonpathogenic
Fusarium oxysporum was devised in the present study. Protoplasts were prepared from three formae speciales (melonis, radicis-lycopersici and fragariae )of F. oxysporum and transformed with a synthetic gene for green fluorescence protein. Transformants were primarily isolated in the presence
of hygromycin B and then screened by the emission of bright green fluorescence. Roots of melon seedlings were inoculated with
fluorescing microconidia of these fungi, and fungal infection behavior was traced. Using fluorescence microscopy, we directly
observed not only the fungus at the root surface, but also the mycelia elongating in the trachea of roots. Both pathogenic
and nonpathogenic fungi germinated and hyphae elongated superficially on the surface of root. Only pathogenic fungi caused
root necrosis at the inoculation site. Hyphae grew within the stem to induce constriction or cracking of lower hypocotyls,
then causing wilting of the seedlings. Infection behavior of genetically marked pathogenic and nonpathogenic F. oxysporum could be successfully monitored after inoculation of cotyledons of seedlings.
Received 6 June 2001/ Accepted in revised form 3 August 2001 相似文献
992.
Permethrin resistance in 16 field populations of Colorado potato beetle was established by bioassay. Permethrin-resistant genotypes were detected using two genotyping techniques, bidirectional polymerase chain reaction amplification of specific alleles (bi-PASA) and single stranded conformational polymorphism (SSCP). The bi-PASA technique was 86% and SSCP was 95% reliable. In terms of accuracy, bi-PASA determined the correct genotype compared to the actual sequencing data 98% and SSCP 93% of the time. There was marked correlation between increasing survivorship (increasing LD50values) and increasing proportions of resistant genotypes (increasing percentage of resistant allele). These techniques allowed the detection of a resistant allele 98% of the time when sampling only 384 beetles from an overwintering adult population (4995 beetles/ha) that possessed a 1% resistant allele frequency at a cost of $500/ha, substantiating the cost effectiveness of the genotyping approaches to monitoring. 相似文献
993.
佳多虫情测报灯和普通黑光灯对草地螟种群监测与防治效果比较 总被引:5,自引:0,他引:5
2004-2006年连续3年应用佳多自动虫情测报灯和传统普通黑光灯对草地螟种群监测和诱杀结果表明,两种诱虫灯均可有效监测草地螟种群动态,自动虫情测报灯对高密度草地螟种群诱杀效果显著,诱蛾量明显高于普通黑光灯的,而普通黑光灯对低密度种群诱杀较为有效。两种灯光诱捕器监测的草地螟种群动态变化趋势基本一致,每天诱蛾数呈极显著相关(r2004=0.973、r2005=0.990和r2006=0.981,p<0.01),但黑光灯下草地螟种群始见期较早而终见期较晚。两种灯下诱捕的草地螟雌蛾数均大于雄蛾数,但灯光诱捕器之间诱捕的草地螟雌雄性比差别不大。 相似文献
994.
995.
湖北省甜菜夜蛾田间种群抗药性监测 总被引:20,自引:0,他引:20
2006年采用浸叶法监测了湖北武汉、荆州、宜昌、襄樊和麻城5个地区甜菜夜蛾田间种群对10种药剂的抗药性。结果表明,5个种群对氯氰菊酯均已产生了高水平抗性(抗性倍数50.5~263.6);对毒死蜱属中—高水平抗性(抗性倍数36.0~371.5);对灭多威属低—中水平抗性(抗性倍数7.8~20.7);对虫酰肼、氟啶脲、多杀菌素和甲氨基阿维菌素苯甲酸盐的抗性都处于敏感—中水平抗性;除武汉种群对茚虫威的抗性达到高抗水平外,各种群对甲氧虫酰肼、虫螨腈和茚虫威的抗性都处于敏感—低水平抗性。5个甜菜夜蛾田间种群中以武汉种群和宜昌种群抗性水平相对较高。 相似文献
996.
997.
998.
C. Thrane D. Funck Jensen A. Tronsmo 《European journal of plant pathology / European Foundation for Plant Pathology》2000,106(3):215-225
The antagonistic Trichoderma spp. isolates P1 and T3 differed in their ability to colonize and to compete in sphagnum peat moss and on wood chips. In peat supplemented with straw, isolate T3 produced twice as many colony forming units (cfu) as isolate P1. On wood chips, the two isolates formed a similar number of cfu. When the two Trichoderma isolates were cultivated together approximately 85–90% of the cfu were from T3 on both substrates. The presence of Pythium ultimum in peat amended with straw did not influence the number of Trichoderma cfu formed. The two Trichoderma isolates produced different amounts of hydrolytic enzymes both in liquid cultures and in peat. Seven different enzyme activities were tested. Enzyme production by T. harzianum isolate T3 was less influenced by the type of carbon source amendment than that of isolate T. atroviride P1. Culture filtrates of isolate P1 grown on complex carbon sources were high in endochitinase activity, whereas cellulase and endo-1,3--glucanase activities were more pronounced in filtrates of isolate T3. There was no significant difference between the two isolates in their ability to protect cucumber seedlings against P. ultimum while the combination of the two fungi resulted in significantly less biocontrol than each isolate alone. 相似文献
999.
1000.
Yoshinori MATSUDA Hideyoshi TOYODA Yasunari KATO Koji KAKUTANI Takayuki NAKANISHI Miki BINGO Teruo NONOMURA Seiji OUCHI 《Journal of General Plant Pathology》2000,66(1):59-63
A nonpathogenic mutant of Ralstonia solanacearum was produced by the insertion of transposon Tn4431. The mutagenized gene was then cloned from a genomic DNA library by the
gene tagging method, using the labeled lux operon located on Tn4431 of pUCD623 as a hybridization probe. From nucleotide sequence analysis of the transposon-inserted
genomic clone, the hrpB gene was shown to be disrupted by the inserted transposon. Tomato plants were inoculated with the hrpB-disrupted mutant bacteria, for which multiplication and translocation were then monitored using the colony hybridization
method. In addition, the original pathogenic bacteria in which the lux operon had been functionally ligated with the genomic promoter were also used for inoculation and traced by their bioluminescence.
Multiplication of the hrpB-disrupted mutant was suppressed initially in the invaded root tissues and then in upper hypocotyl after translocation, suggesting
that the pathogenic strain of R. solanacearum overcomes at least two steps of host responses expressed in root and hypocotyl tissues. Thus, our approach for molecular
monitoring of the bacteria enabled us to precisely analyze the infection behavior of the pathogenic bacteria in planta.
Received 16 April 1999/ Accepted in revised form 10 August 1999 相似文献