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Cucumber Leaves (cucumber + leaf)
Selected AbstractsGene Expression Analysis in Cucumber Leaves Primed by Root Colonization with Pseudomonas chlororaphis O6 upon Challenge-Inoculation with Corynespora cassiicolaPLANT BIOLOGY, Issue 2 2004M. S. Kim Abstract: Root colonization by Pseudomonas chlororaphis O6, a non-pathogenic rhizobacterium, induced systemic resistance in cucumber against target leaf spot caused by Corynespora cassiicola. A cDNA library was constructed using mRNA extracted from cucumber leaves 12 h after inoculation with C. cassiicola, using plants colonized by O6. To identify genes involved in O6-mediated induced systemic resistance (ISR), we employed a subtractive hybridization method using mRNAs extracted from pathogen-challenged cucumber leaves of plants lacking colonization. Differential screening of the cDNA library led to the isolation of six distinct genes encoding a GTP binding protein, a 60S ribosomal protein, a hypersensitive-induced reaction protein, a ubiquitin extension protein, a pyridine nucleotide-disulfide oxidoreductase, and a signal recognition particle receptor. Expression of these genes was not induced by O6 colonization alone. Rather, transcript accumulation of these genes increased significantly faster and stronger in the O6 colonized than in non-colonized plants after challenge infection. Therefore, O6-mediated ISR may be associated with an enhanced capacity for the rapid and effective activation of cellular defence responses after challenge inoculation. [source] Endopeptidase Isoenzyme Characteristics in Cucumis sativus Leaves During Dark-induced SenescenceJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 4 2007Peng Zhang Abstract The changes and characteristics of endopeptidase (EP) isoenzymes in cucumber (Cucumis sativus L.) leaves during dark-induced senescence were investigated by activity staining after gradient-polyacrylamide gel electrophoresis (G-PAGE) containing co-polymerized gelatin as substrate. The results showed that both the chlorophyll and the protein contents of leaves were decreased, and the protein degradation was correlated with the increase of proteolytic activity during the course of leaf senescence. Meanwhile, nine cucumber endopeptidases isoenzymes (CEP) with 140, 120, 106, 94, 76, 55, 46, 39 and 35 kDa molecular weights were detected. Four of these, CEP2, 3, 4 and CEP9 appeared all the time, but the changes of the activity were different during incubation. Another four CEPs (CEP5, 6, 7 and CEP8) whose activities increased with dark-induced time were only detected in senescent leaves. Furthermore, the biochemical properties of these nine CEP were also characterized. All the CEPs had high activities from 35 °C to 45 °C, and the optimum temperature was found to be 40 °C. However, the activities of CEPs were not detected below 25 °C or over 60 °C. The activity bands appeared at a wide range of pH from 5.0 to 9.0, but the optimum pH was found at 7.0. No CEPs were detected at pH 4 or pH 10. By inhibition analysis we concluded that CEP2, 3, 4 and CEP9 were serine endopeptidases and CEP6 was a kind of cysteine protease. It is suggested that serine endopeptidases might play a major role in cucumber leaf senescence, and for the first time, six senescence-related endopeptidases (CEP1, 5, 6, 7, 8 and 9) were found in cucumber leaves. [source] Effect of additives in aqueous formulation on the foliar uptake of dimethomorph by cucumbersPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 4 2009Ju-Hyun Yu Abstract BACKGROUND: The efficacy enhancement of dimethomorph formulation by several adjuvants is thought to be through increased foliar uptake. In order to identify the most effective adjuvants, the adjuvancy of 36 additives was examined in aqueous formulations in relation to the absorption of dimethomorph by cucumber leaves. RESULTS: Polyethylene glycol monohexadecyl ethers with ethylene oxide (EO) contents of between 7 and 20, polyethylene glycol monooctadecyl ethers with EO contents of between 10 and 20 and polyethylene glycol monooctadecenyl ethers with EO contents of between 6 and 20 were effective adjuvants for promoting dimethomorph uptake from both aqueous acetone solutions and aqueous wettable powder (WP) suspensions into cucumber leaves. Polyethylene glycol monododecyl ethers with EO contents of between 7 and 9 were effective in promoting dimethomorph uptake from aqueous WP suspensions but less effective relative to the other adjuvants tested with aqueous acetone solutions. Foliar uptake of dimethomorph was also facilitated by the addition of methyl hexadecanoate, methyl octadecenoate and methyl octadecadienoate. CONCLUSIONS: Although the foliar uptake of dimethomorph from both aqueous WP suspensions and aqueous acetone solutions was greatest in the presence of fatty alcohol ethoxylates generally having a C16 or C18 lipophile, uptake from aqueous surfactant,acetone solutions was, on average, 7.6-fold greater than that from aqueous WP suspensions containing surfactant. Copyright © 2009 Society of Chemical Industry [source] Influence of foliar and systemically applied azadirachtin on host-plant evaluation behaviour of the sweetpotato whitefly, Bemisia tabaciPHYSIOLOGICAL ENTOMOLOGY, Issue 1 2009JI-HUI WEN Abstract The behaviour of female adult Bemisia tabaci is observed for a period of 20 min after initial contact with untreated cucumber leaves, or leaves either foliar or systemically treated with azadirachtin, to determine whether application of azadirachtin affects the host-evaluation behaviour and whether the behaviour on treated leaves differs between application methods. Application of azadirachtin deters settling of the whiteflies on host plants. The whiteflies probe for shorter duration and less frequently but spend longer and engage more frequently in labial grooming on treated leaves than on untreated leaves. Behavioural transition between probing and other behavioural elements is less common, and that between labial grooming and other behavioural elements more common, on both treated leaves than on untreated leaves. No difference is detected in the host-evaluation behaviour of B. tabaci between leaves foliar treated and systemically treated with azadirachtin. [source] Gene Expression Analysis in Cucumber Leaves Primed by Root Colonization with Pseudomonas chlororaphis O6 upon Challenge-Inoculation with Corynespora cassiicolaPLANT BIOLOGY, Issue 2 2004M. S. Kim Abstract: Root colonization by Pseudomonas chlororaphis O6, a non-pathogenic rhizobacterium, induced systemic resistance in cucumber against target leaf spot caused by Corynespora cassiicola. A cDNA library was constructed using mRNA extracted from cucumber leaves 12 h after inoculation with C. cassiicola, using plants colonized by O6. To identify genes involved in O6-mediated induced systemic resistance (ISR), we employed a subtractive hybridization method using mRNAs extracted from pathogen-challenged cucumber leaves of plants lacking colonization. Differential screening of the cDNA library led to the isolation of six distinct genes encoding a GTP binding protein, a 60S ribosomal protein, a hypersensitive-induced reaction protein, a ubiquitin extension protein, a pyridine nucleotide-disulfide oxidoreductase, and a signal recognition particle receptor. Expression of these genes was not induced by O6 colonization alone. Rather, transcript accumulation of these genes increased significantly faster and stronger in the O6 colonized than in non-colonized plants after challenge infection. Therefore, O6-mediated ISR may be associated with an enhanced capacity for the rapid and effective activation of cellular defence responses after challenge inoculation. [source] | ||||||||||