The Construction Of Transgenic Maize And Arabidopsis With ZmNAC And ZmCCaMK Genes

It has been proved that ZmNAC and ZmCCaMK involved in the antioxidant defense by using the transiently overexpressed or silenced system in mesophyll protoplasts in our lab.To further study their functions under abiotic stresses.two systems of transformation were used for these genes:one is using maize callus as the transformation target,while the other one is using embryos.The results showed that when used the callus as target,the totipotency is much higher than other tissues.especially the type ? callus which can regenerate and differentiate more easily;but this transgenic system performed high proportion of callus browning,and this resulted in few resistant callus and regenerate plants,only 3 regenerate plants were transplanted successfully;the vegetative growth period of regeneration plants were shortened,while the tassel were not developed.Finally,the PCR identification showed that no positive plants were obtained.This system from immature embryos dissection to plant regeneration took about 160 days.On the contrary,using embryos as target came to be more easily and reduced the loss of callus from browning.Totally,58 resistant plants were regenerated successfully,in which 52 plants were transplanted to greenhouse,and then 44 plants were identified positive.Now,the TO seeds were harvested.It took about 70 days for regeneration and showed higher transgenic rate.Thus the maize transgenic system was established already.Because it takes so much time to obtain homozygous transgenic maize,in this paper we also constructed the transgenic Arabidopsis thaliana that overexpress the ZmCCaMK and ZmNAC,and studied the functions of these genes in response to abiotic stresses.To analysis the functions of the ZmCCaMK and ZmNAC in Arabidopsis under salt and drought stress,the WT and transgenic plants were exposed to NaCl and PEG-6000 treatment,then the germination rate,root length,relative water content,MDA content,conductivity and proline content were measured and analysized.The results showed that,transgenic plants' germination rate,root length,relative water content and proline content were higher than WT,while MDA content and conductivity is lower than WT.These indicated that ZmCCaMK and ZmNAC involved in the response to salt and drought stresses,and can decrease the effect of hurt induced by salt stress and drought stress,even more they can improve the resistance to salt and drought stresses of plants.