共查询到20条相似文献，搜索用时 31 毫秒
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The sensitivity of Venturia inaequalis field isolates to inhibitors of the cytochrome bc1 complex at the Qo site (QoIs) was characterised at the molecular, biochemical and physiological level, and compared to other respiration inhibitors. Comparison of a sensitive and a QoI-resistant isolate revealed very high resistance factors both in mycelium growth and spore germination assays. Cross-resistance was observed among QoIs such as trifloxystrobin, azoxystrobin, famoxadone, strobilurin B and myxothiazol. In the mycelium growth assay, antimycin A, an inhibitor of the cytochrome bc1 complex at the Qi site, was less active against the QoI-resistant than against the sensitive isolate. The mixture of QoIs with salicylhydroxamic acid (SHAM), an inhibitor of the alternative oxidase, exerted synergistic effects in the spore germination but not in the mycelium growth assay. Thus, the cytochrome and the alternative respiration pathways are assumed to play different roles, depending on the developmental stage of the fungus. Induction of alternative oxidase (AOX) by trifloxystrobin was observed in mycelium cells at the molecular level for the sensitive but not the resistant isolate. Following QoI treatment, respiration parameters such as oxygen consumption, ATP level, membrane potential and succinate dehydrogenase activity were only slightly reduced in Qo-resistant mycelium cells, and remained at much higher levels than in sensitive cells. In contrast, no difference was observed between sensitive and resistant isolates when NADH consumption was measured. Comparison of the cytochrome b (cyt b) gene of the sensitive and resistant isolates did not reveal any point mutations as is known to occur in resistant isolates of other plant pathogens. It is assumed that QoI resistance in V inaequalis may be based on a compensation of the energy deficiency following QoI application upstream of the NADH dehydrogenase of the respiratory chain. 相似文献
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Tian‐Rui Ren Hong‐Wei Yang Xu Gao Xin‐Ling Yang Jia‐Ju Zhou Fu‐Heng Cheng 《Pest management science》2000,56(3):218-226
The paper describes the biophore models of sulfonylurea, imidazolinone, triazolopyrimidinesulfonamide and 5‐pyrimidyltriazolo‐3‐sulfonamides established by the Apex‐3D method. A series of N‐phenylsulfonyl‐N ′‐(thiadiazol‐2‐yl)oxamides and three types of triazolopyrimidinesulfonamide were synthesised and their herbicidal activities determined to assess the validity of the model. In general, the model gave useful leads to activity, although the actual level was not always predicted accurately. In only a few cases did compounds predicted as being active prove to be inactive in the bioassay, and compounds with little or no activity were clearly indicated. As a result of this work, the compound N,N ′‐[1‐(5,7‐dimethyl‐1,2,4‐triazolo[1,5‐a]pyrimidin‐2‐yl‐thio)butane‐2,3‐di‐imino]bis(2‐chlorobenzenesulfonamide) was selected as showing good activity against a range of species, and will be used as a lead for further development. © 2000 Society of Chemical Industry 相似文献
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Repeated use of ACCase‐ and ALS‐inhibiting herbicides in northern Greece has resulted in the evolution of a population of Lolium rigidum resistant to diclofop and chlorsulfuron. The biotype from Athos was highly resistant to diclofop and also exhibited differential cross‐resistance to clodinafop, fluazifop, tralkoxydim and sethoxydim. Assay of ACCase activity confirmed that the resistant biotype was tenfold more resistant to diclofop than the susceptible biotype, suggesting that the resistance mechanism could involve an altered target site. The diclofop‐resistant biotype has also exhibited multiple resistance to chlorsulfuron and the mechanism for this is unknown. Seed‐bioassay was found to be a rapid, cheap and reliable method to identify populations of L rigidum resistant to ACCase inhibitors and chlorsulfuron. Moreover, root elongation in the seed bioassay was more sensitive to ACCase inhibitors and chlorsulfuron than shoot elongation. © 2000 Society of Chemical Industry 相似文献
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V Kati L Scarabel D Thiery‐Lanfranchi V Kioleoglou S Liberopoulou C Dlye 《Weed Research》2019,59(5):367-376
The issue of cross‐ or multiple resistance to acetolactate synthase (ALS) inhibitors and the auxinic herbicide 2,4‐D was investigated in Papaver rhoeas L., a common and troublesome weed in winter cereals, in a broad‐scale study across four European countries. A combination of herbicide sensitivity bioassays and molecular assays targeting mutations involved in resistance was conducted on 27 populations of P. rhoeas originating from Greece (9), Italy (5), France (10) and Spain (3). Plants resistant to the field rate of 2,4‐D were observed in 25 of the 27 populations assayed, in frequencies ranging from 5% to 85%. Plants resistant to ALS‐inhibiting herbicides (sulfonylureas) were present in 24 of the 27 populations, in frequencies ranging from 4% to 100%. Plants resistant to 2,4‐D co‐occurred with plants resistant to sulfonylureas in 23 populations. In four of these, the probability of presence of plants with cross‐ or multiple resistance to 2,4‐D and sulfonylureas was higher than 0.5. ALS genotyping of plants from the field populations or of their progenies, identified ALS alleles carrying a mutation at codon Pro197 or Trp574 in 2,4‐D‐sensitive and in 2,4‐D‐resistant plants. The latter case confirmed multiple resistance to 2,4‐D and ALS inhibitors at the level of individual plants in all four countries investigated. This study is the first to identify individual plants with multiple resistance in P. rhoeas, an attribute rarely assessed in other weed species, but one with significant implications in designing chemical control strategies. 相似文献
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1,5‐Diphenyl‐1‐pentanone (A) and 1,5‐diphenyl‐2‐penten‐1‐one (B) are natural products extracted for the first time from Stellera chamaejasme. Laboratory bioassay showed that the two products have strong contact activity and very good anti‐feedant activity against Aphis gossypii and Schizaphis graminum. Both products showed dose‐dependent relationships for both forms of activity against the two aphids, the contact activity of B being about twice that of A. Both products were inferior to methomyl in contact activity but superior in anti‐feedant activity against the two aphids. This is the first report of aphicidal activity in these two compounds, which may represent a new class of aphicide. © 2001 Society of Chemical Industry 相似文献
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A glycoprotein α‐amylase inhibitor from Withania somnifera differentially inhibits various α‐amylases and affects the growth and development of Tribolium castaneum 
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下载免费PDF全文 Sainath S Kasar Kiran R Marathe Amey J Bhide Abhijeet P Herwade Ashok P Giri Vijay L Maheshwari Pankaj K Pawar 《Pest management science》2017,73(7):1382-1390
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Callose and β‐1,3‐glucanase inhibit Phytophthora cinnamomi in a resistant avocado rootstock 下载免费PDF全文
下载免费PDF全文 N. van den Berg J. B. Christie T. A. S. Aveling J. Engelbrecht 《Plant pathology》2018,67(5):1150-1160
Phytophthora root rot (PRR) of avocado, caused by Phytophthora cinnamomi, is a significant threat to sustainable production wherever the crop is grown. Resistant rootstocks in combination with phosphite applications are the most effective options for managing this disease. Recently, the mechanisms underpinning PRR resistance have been investigated by the avocado community. Here, biochemical assays and confocal and scanning electron microscopy were used to investigate early defence responses in PRR resistant and ‐susceptible avocado rootstocks. Zoospore germination and subsequent hyphal growth for the pathogen were significantly inhibited on the surface of resistant avocado roots. When penetration occurred in the resistant R0.06 rootstock, callose was deposited in the epidermal cells, parenchyma and cortex of roots. In addition, β‐1,3‐glucanase was released early (6 h post‐inoculation, hpi) in response to the pathogen, followed by a significant increase in catalase by 24 hpi. In contrast, susceptible R0.12 roots responded only with the deposition of lignin and phenolic compounds incapable of impeding pathogen colonization. In this study, PRR resistance was attributed to a timely multilayered response to infection by P. cinnamomi. 相似文献