Comparison Of Growth, Physiological Characteristics And Agronomic Traits Of Transgenic Maize With BADH Gene And The Receptor

Maize(Zea mays L.),which plays a considerable role,is important food crops in China.Nowadays,it’s extremely urgent to cultivate drought and salt resisting maize due to present soil status.Betaine is an effective osmoprotectant,which contributes to drought tolerance by maintaining osmotic balance.It is of great significance to gain drought-tolerant maize by transforming BADH(Betaine aldehyde dehydrogenase)gene into maize genome.In this study,the BADH maize of T4 that obtained by the method of pollen-mediated method,were used as materials.We investigated the growth,physiological and metabolism characteristics,agronomic trait of transgenic maize seedlings with BADH gene and their untransgenic counterparts under well-irrigated conditions and drought stress.The aim of the study is to provide some basic knowledge for the genetically modified crops via this transformation method,which will benefit to understand the substantial equivalence of the genetically modified crops and their untransformed receptor.The results were as follows:1.Under drought stress,the contents of soluble sugar,soluble protein,proline and glycinebetaine of transgenic seedlings were significantly higher than the untransformed receptor;the contents of superoxide anion free radical,malondialdehyde and electrical conductivity of transgenic seedlings were significantly lower than the untransformed receptor;SOD and POD activity of transgenic maize were higher than the untransformed receptor.2.Under drought stress,the contents of soluble sugar,soluble protein,proline and glycinebetaine of transgenic seedlings were33.45%,92.65%,690% and 220% higher than the untransformed control,respectively,indicating that the BADH maize performed superior drought tolerance.Under normal water conditions,the contents of soluble sugar,proline and glycinebetaine were 4.42%,21.72% and 9.5% higher than the control,respectively.And the content of soluble protein of transgenic seedlings was 67.69%lower than the untransformed receptor.We owe it to a self-regulation mechanism where these plants maintain normal metabolism where these plants maintain normal metabolism by re-establishing the cellular homeostasis.3.Under drought stress,the electrical conductivity,superoxide anion free radical content and malondialdehyde content were 66%,138% and 127% lower than the untransformed control,respectively,indicating suffering less damage from lipid peroxidation of BADH maize leaves.Under normal water conditions,the electrical conductivity and superoxide anion free radical content were 185%and 91.3% higher than the control,respectively,and malondialdehyde content was 127% lower than the control,indicating that BADH maize leaves suffered more damage from lipid peroxidation.4.Under drought stress,SOD and POD activity of transgenic maize were 33% and 36% higher than the untransformed control,respectively;under normal water conditions,SOD and POD activity of transgenic maize were 80% and 9.8% higher than the untransformed control,respectively,reflecting that BADH maize has superior ability of scavenging reactive oxygen.5.We observed and analyzed characteristics of maize ears between transgenic maize and their untransformed control,the results showed no significant difference of agronomic trait between2 lines.6.No significant difference exhibited for the quantity of bacteria,actinomycetes and fungi from rhizosphere soil of transgenic maize and the untransformed control,which preliminary verified that the same influences on rhizosphere soil microbial diversity from 2 lines seedings.7.The results of semi-quantitative RT-PCR and real-time PCR analysis showed that BADH gene has already expressed in transgenic plants.And under drought stress,the relative expression of BADH gene was higher than under that under well-irrigation conditions.