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Ethylene-releasing Compound (ethylene-releasing + compound)
Selected AbstractsThe role of olfactory stimuli in the location of weakened hosts by twig-infesting Pityophthorus spp.ECOLOGICAL ENTOMOLOGY, Issue 1 2001Pierluigi Bonello Summary 1. Senescing, shade-suppressed, or broken branches of Monterey pine Pinus radiata are infested by twig beetles in the genus Pityophthorus (Coleoptera: Scolytidae). The studies reported here tested whether twig beetles can discriminate between healthy and pitch canker-diseased branches, whether diseased branch tips produce more ethylene than undamaged controls, and whether ethylene and other volatiles, produced by the plant in response to tissue damage, are utilised by twig beetles in host location. 2. Significantly greater numbers of twig beetles were reared from pitch canker-symptomatic than from pitch canker-asymptomatic branches of Monterey pine collected in the field. 3. Needles of Monterey pine branches inoculated with the pitch canker fungal pathogen Fusarium circinatum produced significantly higher levels of ethylene than needles of control branches, and this was evident just prior to, and during, symptom expression. 4. In trapping studies in which pheromone production was prevented, there was no evidence of attraction of twig beetles to a source of ethylene alone, to cut host branches, or to cut branches treated with the ethylene-releasing compound, ethephon. The results suggest that twig beetles identify weakened branches after landing. [source] Expression of a transcription factor (FsERF1) involved in ethylene signalling during the breaking of dormancy in Fagus sylvatica seedsPHYSIOLOGIA PLANTARUM, Issue 3 2005Jesús Angel Jiménez By means of reverse transcriptase-polymerase chain reaction, using degenerate oligonucleotides conserved among ethylene-responsive transcription factors, we have isolated and characterized a cDNA clone encoding a protein involved in ethylene signalling during the breaking of dormancy in Fagus sylvatica L. seeds. This clone, named FsERF1, exhibits high homology to ethylene-responsive factors (ERFs) from several plant species. The expression of FsERF1 as a fusion protein in Escherichia coli confirmed that it was able to bind to the GCC box, a cis element present in the promoters of several ethylene-responsive genes, corroborating its role as a DNA-binding protein. Northern analysis showed that the transcript levels increased when dormancy was broken by ethephon (an ethylene-releasing compound), or by moist prechilling pretreatment at restricted water content, and were almost undetectable when seeds remained dormant by the addition of abscisic acid, aminooxyacetic acid (an ethylene biosynthesis inhibitor) or warm pretreatment, and when seeds were artificially dried, suggesting that FsERF1 function may be more closely related with the transition from seed dormancy to germination than with responses to drought stress mediated by ethylene. [source] Exogenous ethylene stimulates the long-term expression of genes related to anthocyanin biosynthesis in grape berriesPHYSIOLOGIA PLANTARUM, Issue 2 2003Ashraf El-Kereamy The treatment of grape berries (Vitis vinifera L. cv. Cabernet Sauvignon) with the ethylene-releasing compound, 2-chloroethylphosphonic acid (2-CEPA), at veraison is a method known to enhance grape skin colour. We observed that it produced a 6-fold increase, up to 30 pmol g,1 FW, of the cluster internal ethylene compared to untreated controls within the 24 h following treatment. This ethylene upsurge was associated with increased levels of chalcone synthase (CHS) and flavanone 3-hydroxylase (F3H) transcripts, which persisted over the following 20 days. Transcript levels of leucoanthocyanidin dioxygenase (LDOX) and UDP glucose-flavonoid 3- O -glucosyl transferase (UFGT) were similarly enhanced by 2-CEPA, although to a lesser extent. The effect on UFGT was confirmed at the protein level by an immunoblot analysis. The transcript accumulation of dihydroflavonol 4-reductase (DFR) was unaffected by 2-CEPA treatment. Examination of the levels of CHS, F3H and UFGT mRNAs in berries during bunch exposure to ethylene, revealed elevated levels of each transcript within the first 6 h of treatment when compared to nonethylene-treated controls. HPLC analyses of berry skin extracts showed that levels of each of the anthocyanins analysed (delphinidin, cyanidin, petunidin, peonidin and malvidin) increased over the 10 days following the ethylene burst, and decreased thereafter. However, anthocyanin levels at harvest were still higher in ethylene treated grapes than in controls. This data is the first evidence that ethylene triggers gene expression related to anthocyanin synthesis in grapes, and in addition, our results also confirm the existence of other regulatory modes in the anthocyanin biosynthetic pathway. [source] The application of ethephon (an ethylene releaser) increases growth, photosynthesis and nitrogen accumulation in mustard (Brassica juncea L.) under high nitrogen levelsPLANT BIOLOGY, Issue 5 2008N. A. Khan Abstract Ethephon (2-chloroethyl phosphonic acid), an ethylene-releasing compound, influences growth and photosynthesis of mustard (Brassica juncea L. Czern & Coss.). We show the effect of nitrogen availability on ethylene evolution and how this affects growth, photosynthesis and nitrogen accumulation. Ethylene evolution in the control with low N (100 mg N kg,1 soil) was two-times higher than with high N (200 mg N kg,1 soil). The application of 100,400 ,l·l,1 ethephon post-flowering, i.e. 60 days after sowing, on plants receiving low or high N further increased ethylene evolution. Leaf area, relative growth rate (RGR), photosynthesis, leaf nitrate reductase (NR) activity and leaf N reached a maximum with application of 200 ,l·l,1 ethephon and high N. The results suggest that the application of ethephon influences growth, photosynthesis and N accumulation, depending on the amount of nitrogen in the soil. [source] The immediate-early ethylene response gene OsARD1 encodes an acireductone dioxygenase involved in recycling of the ethylene precursor S -adenosylmethionineTHE PLANT JOURNAL, Issue 5 2005Margret Sauter Summary Methylthioadenosine (MTA) is formed as a by-product of ethylene biosynthesis from S -adenosyl- l -methionine (AdoMet). The methionine cycle regenerates AdoMet from MTA. In two independent differential screens for submergence-induced genes and for 1-aminocyclopropane-1-carboxylic acid (ACC)-induced genes from deepwater rice (Oryza sativa L.) we identified an acireductone dioxygenase (ARD). OsARD1 is a metal-binding protein that belongs to the cupin superfamily. Acireductone dioxygenases are unique proteins that can acquire two different activities depending on the metal ion bound. Ectopically expressed apo-OsARD1 preferentially binds Fe2+ and reconstituted Fe-OsARD1 catalyzed the formation of 2-keto-pentanoate and formate from the model substrate 1,2-dihydroxy-3-ketopent-1-ene and dioxygen, indicating that OsARD1 is capable of catalyzing the penultimate step in the methionine cycle. Two highly homologous ARD genes were identified in rice. OsARD1 mRNA levels showed a rapid, early and transient increase upon submergence and after treatment with ethylene-releasing compounds. The second gene from rice, OsARD2, is constitutively expressed. Accumulation of OsARD1 transcript was observed in the same internodal tissues, i.e. the meristem and elongation zone, which were previously shown to synthesize ethylene. OsARD1 transcripts accumulated in the presence of cycloheximide, an inhibitor of protein synthesis, indicating that OsARD1 is a primary ethylene response gene. Promoter analysis suggests that immediate-early regulation of OsARD1 by ethylene may involve an EIN3-like transcription factor. OsARD1 is induced by low levels of ethylene. We propose that early feedback activation of the methionine cycle by low levels of ethylene ensures the high and continuous rates of ethylene synthesis required for long-term ethylene-mediated submergence adaptation without depleting the tissue of AdoMet. [source] | ||||||||||