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The use of crop varieties resistant or tolerant to insect pests or other stress factors is one approach in non‐chemical crop‐protection. Knowledge of the biochemical and molecular background of insect–plant interactions is a prerequisite for optimizing breeding for resistance. However, the resistance genes involved in plant–aphid interactions have so far only been identified and characterized in very few plant species. Our work aims to elucidate the molecular and biochemical mechanisms involved in resistance of apple trees, Malus domestica L. (Rosaceae), against its primary aphid pest, the rosy apple aphid, Dysaphis plantaginea (Passerini) (Homoptera: Aphididae), which is considered a serious economic pest of apple. Gene expression in both resistant and susceptible apple cultivars after infestation with rosy apple aphids was investigated by employing the cDNA‐AFLP method (cDNA–Amplified Fragment Length Polymorphism). From approximately 12 500 cDNA fragments detected on polyacrylamide gels, 21 bands were apparently up‐ or down‐regulated only in the resistant cultivar ‘Florina’ after aphid infestation compared to the susceptible cultivar ‘Topaz’ and/or mechanically wounded or non‐infested leaves. These fragments were cloned, sequenced, and the pattern of gene expression for six fragments was subsequently verified by virtual Northern blots. Sequence comparisons of these fragments to GenBank accessions revealed homologies to already known genes, most of them isolated from Arabidopsis thaliana L. Among them, a putative RNase‐L‐inhibitor‐like protein, a pectinacetylesterase, an inositol‐phosphatase‐like protein, a precursor of the large chain of the ribulose‐1,5‐biphosphate‐carboxylase, and defence‐related genes such as a vacuolar H(+)‐ATPase subunit‐like protein and an ADP‐ribosylating enzyme were identified. The results are discussed in relation to a putative role of these genes in conferring aphid resistance in apple trees. 相似文献
194.
Jacqueline Hirsch Sandhya Galidevara Stephan Strohmeier K. Uma Devi Annette Reineke 《Microbial ecology》2013,66(3):608-620
The entomopathogenic fungus Beauveria bassiana is widely used as a biological control agent (BCA) for insect pest control, with fungal propagules being either incorporated into the potting media or soil or sprayed directly onto the foliage or soil. To gain a better understanding of entomopathogenic fungal ecology when applied as a BCA to the soil environment, a case study using tag-encoded 454 pyrosequencing of fungal ITS sequences was performed to assess the fate and potential effect of an artificially applied B. bassiana strain on the diversity of soil fungal communities in an agricultural field in India. Results show that the overall fungal diversity was not influenced by application of B. bassiana during the 7 weeks of investigation. Strain-specific microsatellite markers indicated both an establishment of the applied B. bassiana strain in the treated plot and its spread to the neighboring nontreated control plot. These results might be important for proper risk assessment of entomopathogenic fungi-based BCAs. 相似文献
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Elizabeth Kecskeméti Arne Brathuhn Karl‐Heinz Kogel Beate Berkelmann‐Löhnertz Annette Reineke 《Journal of Phytopathology》2014,162(9):582-595
Transposons and infection of fungal strains with mycoviruses can have significant effects on distinctive phenotypic traits of phytopathogenic fungi such as mycelial growth and sporulation, pathogenicity or fungicide resistance. Two transposable elements (TE), Boty and Flipper, are known to be associated with the ubiquitous fungus Botrytis cinerea. In addition, the presence of two types of ssRNAsRNA viruses, BVX and BVF, has been reported in B. cinerea. In this study, we assessed the genetic diversity of B. cinerea isolates, all sampled within a small‐sized German viticultural area (‘Rheingau’) by examining and classifying them according to the presence of TEs and mycoviruses. A subset of the isolates was further analysed with microsatellite markers to determine the origin of particular isolates with or without one or both mycoviruses. Virtually all isolates (98%) sampled in two different years (2008 and 2010) were screened positive for the presence of a transposon. Presence of one or both B. cinerea mycoviruses was confirmed for 37% of the analysed isolates sampled in 2010, representing the first record of B. cinerea mycoviruses in German isolates. Assignment on individual B. cinerea isolates to different genetic groups was independent of the presence or absence of a mycovirus or a transposable element, respectively. Furthermore, we found no correlation between the presence of either a mycovirus or a transposable element and different viticultural management practices, soil properties or levels of nitrogen fertilization applied to the respective vineyards. However, mycelial growth of B. cinerea strains containing mycovirus BVF was significantly reduced at lower temperatures. 相似文献
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Background
The expression of glucocorticoid-receptor (GR) seems to be a key mechanism in the regulation of glucocorticoid (GC) sensitivity and is potentially involved in cases of GC resistance or hypersensitivity. The aim of this study is to describe a method for quantitation of GR alpha isoform (GRα) expression using real-time PCR (qrt-PCR) with analytical capabilities to monitor patients, offering standard-curve reproducibility as well as intra- and inter-assay precision. 相似文献199.
Abstract A Pseudomonas sp. strain WR401 was isolated for growth on 3-, 4-, and 5-methylsalicylate. The organism was capable of growth on o -toluate. The data on enzyme activities in cell-free extracts, DHB dehydrogenase and catechol 2,3-dioxygenase, as well as the cooxidation of the substrate analog 2-chlorobenzoate yielding 3-chlorocatechol indicated a pathway for o -toluate degradation through 6-methyldihydrodihydroxybenzoate, 3-methylcatechol and further through the meta -pathway. In contrast to other toluate dioxygenating enzymes found in m - and p -toluate degrading organisms, strain WR401 was able to dioxygenate a wider range of chlorobenzoates including 2-chlorobenzoate. 相似文献
200.
Walter Reineke Hans-Joachim Knackmuss 《Biochimica et Biophysica Acta (BBA)/General Subjects》1978,542(3):424-429
The dehydrogenation of substituted 3,5-cyclohexadiene-1,2-diol-1-carboxylic acids by dihydrodihydroxybenzoic acid dehydrogenases from benzoate grown cells of Alcaligenes eutrophus and Pseudomonas sp. B 13 and 3 -chlorobenzoate grown cells of the latter organism was examined. No significant differences (Km and Vrel values) were detected for the enzymes from both organisms. The same dihydrodihydroxybenzoic acid dehydrogenase is formed in Pseudomonas sp. B13 during growth on benzoate as well as on 3-chlorobenzoate. The lower turnover rates of 3- and 5-chlorodihydrodihydroxybenzoic acid compared to dihydrodihydroxybenzoic acid are counterbalanced by an increase in specific activity. With the exception of 4-substituted dihydrodihydroxybenzoic acids exhibiting relative high Km values, only slight sterical and electronic substituent effects are evident. Reaction rates were never reduced to a critical level. 相似文献