Study On The Role Of Ethylene In Silicon Reducing Damage And Anthocyanin Accumulation In Arabidopsis Under Salt Stress

Silicon(Si)is not only the important elements,but also plays an important role in physiological activities and metabolism regulation in plants.A large number of studies have shown that Si can alleviate damage of plants in salt stress.However,many studies only analyzed at physiological and metabolic level,including Si decreases the damage of membrane lipid peroxidation caused by salt stress through enhancing the activities of antioxidant enzymes.The mechanism of Si alleviated damage of plant in salt stress remains to be further studied.Ethylene is an important gas hormone in plants.It plays a key role in the regulation of plant life activities.In addition,ethylene can promote fruit ripening and also involve in regulation of plant response to abiotic stress injury.And the interaction between ethylene and other regulators also regulates abiotic stress in plant.In order to study whether ethylene is involved in the progress of Si reducing salt stress damage,we use wild type of Arabidopsis(Col-0)and ethylene insensitive mutants as material and change of anthocyanin content as the injury index to study the role and mechanism of ethylene in Si alleviated the damage of salt stress and anthocyanin accumulation in Arabidopsis.The results showed that the contents of anthocyanin were significantly accumulated under NaCl stress in Col-0 and the damage caused by NaCl stress was relieved by Si.Under NaCl stress,Co2+(ethylene synthesis inhibitor)or Ag+(ethylene receptor inhibitor)could block the relieved effect of Si on the injury of salt stress.In the presence of ACC,Si can reduce the content of anthocyanin in Col-0 under Co2++NaCl treatment,but it can not reduce the accumulation of anthocyanin in Ag+NaCl treatment.Therefore,it is speculated that ethylene synthesis and ethylene signaling are all involved in Si reduced the damage of salt stress.And ethylene signaling may play an important role in this process.The further study using ethylene receptor mutants etrl-3 and etr2-1,ethylene insensitive mutants ein2-1 and ein3/eill showed that Si can not alleviate anthocyanin accumulation in all the mutants under salt stress.On the contrary,Si can partially reduce anthocyanin accumulation in EIN3ox.The analysis of gene expression of ethylene signaling in Col-0 under different treatment conditions indicated that the expression of ETR1-3,ETR1-2,EBF1 and EBF2 under salt stress can be down regulated by Si,but Si was almost no effect on the expression of EIN2 under salt stress.Thus,the relieved effect of Si on the damage of salt stress may be obtained from maintaining the stability of EIN3 gene of ethylene signaling.