Cloning Of IRT1 Homologs From Sedum Alfredii And Physiological Analysis Of NfSOD Transgenic Sedum Alfredii Under Various Stresses

Due to industrial production,mineral extraction,waste emissions,China's environmental heavy metal pollution situation is grim,which seriously impact on crop yield and quality.Heavy metals can also be enriched in the human body through the food chain,causing distortion of the human body,cancer and even death.Phytoremediation is currently an important emerging technology in the treatment of heavy metal pollution,favoured by the world's governments and researchers of all ages,which uses plants to absorb heavy metals polluted environment,and through mowing,and focused approach to the transfer of the plant,in situ cleaning up the environment,an effiicient,economical,and no secondary pollution.Cloning important genes related to plants absorbing and withstanding heavy metal enrichment,is important to the genetic improvement of plants,the development of phytoremediation of heavy metal pollution in the environment.Mines ecotype Sedum alfredii Hance zinc/cadmium hyperaccumulator,with a strong tolerance to cadmium and enrichment capabilities found in China,has broad application prospects in phytoremediation of heavy metal contamination of the environment.In this paper,a method using RACE and TAIL method,respectively,cloned NSaIRT1 of non-hyperaccumulating ecotype S.alfredii and SaIRTI of hyperaccumulating ecotype S.alfredii cloned genes.Full-length of SaIRTI is 1930bp,its coding region is 1091bp,with a 859bp intron.Full-length of NSa1RT1 gene is 1616bp,its coding region is 1091 bp,with a 545bp intron.The consistency of the coding region of the nucleotide sequence of the gene SaIRTlandNSaIRT1 is 94.12%?The consistency of the predicted amino acid residue sequence of the gene SaIRT1 and NSaIRT1 is 96.08%?Though Bioinformatic analysis,SaIRT1 and NSaIRT1 transporter protein is likely cell membrane protein.After Cd treatment,SaIRTI gene is mainly expressed in the roots of hyperaccumulating ecotype S.alfredii,in the stem has weak expression,the expression is not detected in leaves.NSaIRT1 gene expression in the main roots of non-hyperaccumulating ecotype S.alfredii,expression has not been detected in the stems and leaves Thus,the difference of introns between SaIRT1 and NSaIRT1 gene can be used to identify hyperaccumulating ecotype S.alfredii and non-hyperaccumulating ecotype S.alfredii.In addition,introns may have important functions in the in the process of evolving into hyperaccumulating ecotype S.alfredii.Application of transgenic phytoremediation of heavy metal pollution in the environment is an important strategy for the development of phytoremediation technology.SOD has a clear role of reactive oxygen species,transfered SOD gene can improve plant resistance to abiotic stresses such as heat,drought,etc..In this paper found that transfered drought-tolerant cyanobacteria Nostoc NfSOD gene hyperaccumulating ecotype S.alfredii,at high temperature and osmotic stress,the growth of transgenic plants is slow,photochemical efficiency(Fv/Fm)decreased,and the accumulation of heavy metals cadmium efficiency also declined.In addition,transfered NfSOD gene hyperaccumulating ecotype is in severe chlorosis under high temperature stress,and loss of green under osmotic stress is not obvious.The experiments show that the transfered NfSOD gene hyperaccumulating ecotype S.alfredii have low resistance which may accumulate and particularity of type belonged to the crassulaceae reliated to its mechanism remains to be further explored.