Ethylene Is Involved In Hydrogen Gas-induced Adventitious Root Development In Cucumber And Its Analysis Of Differential Protein Expression

Adventitious root development is affected by many factors.In order to improve the efficiency of plant roots,studying the adventitious rooting mechanism is one of the key aspects,which is important to promte some good varieties‘ vegetative propagation and the development of agriculture,forestry and gardening.Several researchers have reported that hydrogen(H2)plays roles as a physiological signal molecule and a bioactive small molecule in plant cells,including the regulation of root development.As a gaseous phytohormone,ethylene(ETH)plays important physiological actions in diverse developmental processes and it is also involved in response to biotic and abiotic stimuli and stresses in plants.Also,it may act on root development and growth at different levels.It is well known that H2 and ETH function as important signaling molecules involved in plant adventitious rooting.However,relatively little work about the ―cross-talk‖ be-tween H2 and ETH during adventitious root development has been done.Therefore,to elucidate the molecular network between H2 and ETH in plants,we investigate the roles and relationship of ETH and NO dturing adventitious rooting process in cucumber(Cucumis sativus ?Xinchun 4‘).The main experimental results as follows:1.When compared with the control,HRW and ethylene donor Ethrel promoted the formation of adventitious root in cucumber and increased the root number.The effects of ETH on adventitious rooting in cucumber explants were dose-de-pendent.The most effective concentrations of HRW and Ethrel aqueous solution under our experimental conditions are 50%,0.5 μmol · L-1,respectively.ETH inhibitors,aminoethoxy vinylgly-cine(AVG)and(Ag NO3),could inhibite adventitious root formation in cucumber and reverse the promo-tive effects of H2 partly.Thus,it indicates that ETH may be a downstream messenger for H2 to promote adventirious rooting in cucumber.2.PH 4–7 immobilized p H gradient(IPG)strips(17 cm,nonlinear;Bio-Rad),800 μg sample loading volumes and 12% separation gel concentration are most suitable condition for isoelectric focusing of the explants‘ total protein in cucumber.3.Proteomics showed that 26 differentially expressed protein spots could be identified treat with 50% HRW;14 differentially expressed protein spots could be identified treat with 0.5 μmol · L-1 Ethrel;15 differentially expressed protein spots could be identified treat with 0.5 μmol · L-1 Ethrel treat with 50% HRW+0.5 μmol · L-1 Ethrel;11 differentially expressed protein spots could be identified treat with 50% HRW+0.3 μmol · L-1 AVG.4.A total of 60 protein spots that showed significant changes were selected to for MALDI TOF/TOF MS/MS.Among these,53 proteins were successfully identified.The rest of the seven proteins are unknown.The 60 proteins were classified according to its function,which is divided into nine categories: photosynthesis-related proteins,energy metabolism-related proteins,stress and defence response,translation and transcription-related proteins,protein folding,modification and degration-related proteins,amino and metabolism-related proteins,signal transduction1-related proteins,cellular cytoskeleton-related proteins,and unknown proteins.5.Ethylene is involved in hydrogen gas-induced adventitious root development in cucumber by indicating photosynthesis-related proteins,protein folding,modification and degration-related proteins,translation and transcription-related proteins,amino and metabolism-related proteins.Taken together,we investigated that the mechanism of HRW and ETH promoted the formation of adventitious root in cucumber from the pharmacological and proteome aspects,and indicated the relationship between H2 and ETH during adventirious rooting.The research provided an important theoretical basis for further study of signaling molecules involved in adventitious rooting and has a vital significance for the mechanism research on adventitious roots of plants.