Study On Salicylic Acid Production And Iron Metabolism Characteristic And The Relationship To NO Signal Transduction In Chorispora Bungeana Under Low Temperature Condition

Chorispora bungeana fisch & C.A.Mey(C.bungeana)is an alpine subnival plant species that is highly capable of resisting freezing environment.This research tested the way of the NO production,production of salicylic acid and effect of nitric oxide on content of salicylic acid and CbFer,FRO1 expression signal tansduction in Chorispora bungeana under low temperature condition(4℃,0℃,-4℃)systematically,The special cold resistance ability of Chorispora bungeana shows in the following aspects:1.The NO content was increased under cold stress.The research shows that NO is produced by NOS way and NR way under cold stress with the cold time and cold intension in suspension cells of Chorispora bungeana.2.The results showed that the SA content was increased under cold stress with the cold time and cold intension then dropped to a higher level than that in normal suspension cells.3.This research showed that SNP can induce the production of SA under different temperature.Correspondingly,LNNA and PTIO inhibited the production of SA,but the SA content remained relatively stable under the treatment of NAN₃.Chorispora bungeana under cold stress presented higher levels of SA compared with normal temperature condition.Under compound treatment of SNP,LNNA,PTIO and NaN₃,the inhibition of LNNA,PTIO to SA was weakened by SNP.These results suggest that maybe the SA acts as a download signal moleculer to enhance the tolerance to low temperature of Chorispora bungeana.4.FRO1,FRO2 core sequence were cloned in Chorispora bungeana using reverse transcription-PCR method.Sequence analysis revealed that FRO1 and FRO2 were highly homologous to At FRO1(90%)and At FRO2(83%).Real-time PCR analysis revealed that CbFer,FRO1 expression has a close relationship with cold stress.CbFer and FRO1 play an important role in the signal transduction to resist cold stress in Chorispora bungeana.This phenomenon reflects fitly that Chorispora bungeana has the ability to adapt to acute temperature change in the growth environment.5.It is revealed that both in shorten and additional Fe nutrition condition,CbFer and FRO1 expression can be enhanced.This result indicates that iron is a main factor in the regulating of CbFer and FRO1 gene expression. 6.The results of Real-time PCR revealed that LNNA,PTIO,NaN₃ inhibited the CbFer and FRO1 expression.And SNP induced the CbFer and FRO1 expression.Those indicated NO may play key roles in Fe metabolism.In conclusion,the NO producted by NR and NOS can induce the tolerance of cold stress of Chorispora bungeana.The SA and the CbFer,FRO1 expression induced by NO is a very important component part of low temperature tolerance.