Preparation Of P_ObgC1-GUS Transgenic Rice And Expression Analysis Of Selenium Treatment

Selenium is a trace element essential to animals and plants.As an important food crop in China,the quality of rice is closely related to selenium content in the grain.Selenium-enriched rice has higher nutritional value than ordinary rice.Treatment with appropriate concentration of selenium can increase photosynthesis efficiency and promote rice growth.In this study,we found that treatments with different concentrations and different valences of selenium significantly affected the transcription levels of the key gene for chloroplast development,OsObgC1.In order to further analyze the molecular mechanism of selenium-regulated OsObgC1 gene expression,selenium treatment of wild-type rice was carried out in different light/dark conditions,and both root and leave applications of selenium wereinvestigated.It was found that low concentrations（10,20,30,40μmol/L）could increase the expression of OsObgC1;the regulation of OsObgC1 transcription by selenium was not limited by the light factor,and leave application of selenium also altered OsObgC1 transcription levels.To further validate these results,we constructed P_ObgC1-GUS transgenic rice.Transgenic rice seedlings were treated with selenate or selenite and then used for GUS tissue staining.It was found that 10μmol/L selenate or selenite treatment increased the expression of OsObgC1,however,application of 100μmol/L selenate or selenite caused a decrease in the expression of OsObgC1.Wild type rice was treated with different concentrations of selenium and selenium at different concentrations.Through phenotypic observations,chlorophyll fluorescence and chlorophyll content were determined and selenate and selenite were promoted（10,20,30,40μmol/L）.In rice growth,selenate and selenite（50,60,70,80,90,100μmol/L）inhibited rice growth.10μmol/L selenate and selenite increased chlorophyll fluorescence and chlorophyll content,and 50 and 100μmol/L selenium treatment decreased chlorophyll fluorescence and chlorophyll content.Our data revealed the mechanism of selenium-promoted rice chloroplast development at molecular level and may provide theoretical support for selenium fertilizer application and slelnium-enriched rice production.