Study On OsMT Gene Resistance Characteristics Of Heavy Metals

MT?metallothionein,MT?is a kind of small molecule protein and polypeptide which can be combined with heavy metal and rich in cysteine.It is widely distributed in the biology.In recent years,the study of metallothionein has been deepened.Many evidence suggests that metallothionein is not only involved in the storage,transport and metabolism of trace elements in the body,but also has the effects of antagonizing ionizing radiation,scavenging oxygen free radicals and heavy metal detoxification,Delaying aging and certain diseases.At present,the plant metallothionein than the animal metallothionein due to the small amount and easy to oxidize,making the study lagging behind.In this study,four rice metallothionein?OsMT?genes with cis-acting elements associated with heavy metal stress were selected in the promoter region by bioinformatics analysis.The mechanism of response and tolerance to heavy metal stress was explored by means of yeast complement,atomic spectroscopy and infrared spectroscopy.The results are as follows:The expression of OsMT gene was detected by heavy metal?Cd,Cu,Zn?,salt stress?NaCl?,osmotic stress?mannitol?,oxidative stress?H2O2 and methyl violet?and plant hormone JA.Rice root,but not in rice leaves,it is assumed that OsMT genes mainly respond to adverse stress in the root.Construction of PYES260-OsMT vector and expression of four OsMT genes in metal-deficient yeast ?zrc1,?ycf1 and ?cup2.The results showed that OsMT gene had complementary effects on three?Cd,Cu,Zn?metal-deficient yeasts.The results showed that under the control of 0.1 mM Cd,the OsMT gene deficient yeast was higher than that of the untreated yeast.And the growth status of yeast under heavy metal stress was measured.The results showed that transgenic yeast could increase the growth of mutant,Suggesting that the OsMT gene increases the tolerance of yeast to heavy metals.The OsMT-GST protein expression vector was constructed by PGEX4T-3,and four proteins were successfully induced and purified.By measuring the growth status of Rossetta strain under heavy metal stress,the experiment showed that the strainsexpressing four kinds of proteins could improve the tolerance to heavy metals.The GST-OsMT-4c and Cd²⁺ chelate were analyzed by UV spectroscopy.The results showed that the peaks were observed at 250 nm,and the fluorescence spectra of GST-OsMT-4c and Cd²⁺ chelate were observed.The analysis showed a significant change in the peak at 2493 cm^-1,The prediction is that the GST-OsMT-1-4c and the Cd²⁺chelate are the combination of the sulfhydryl and Cd²⁺ in OsMT-1-4c protein.