The Transcriptome And Proteome Research For Selenium Tolerance Of Hyperaccumulator Plant Cardanime Hupingshanensis

Selenium is an essential and beneficial mineral element for animal and plant,and it also play an important part in our human health,but excessive selenium is toxic.Iodinated thyroidine deiodinase,thioredoxin reductase,glutathione peroxidase and selenoprotein family protein are involved in the physiological process of maintaining the dynamic equilibrium of redox,anti-oxidation,normal thyroid hormone metabolism,prevention neurodegenerative lesions and cancer,optimizing the immune response,cell proliferation and survival.Selenium and sulfur have similar chemical properties,so it can participate in the metabolism process of sulfur within the cell.Though high concentration of selenium is toxic to plants,our human also need the organic selenium enriched by plants for the supplement of selenium.Development of selenium hyperaccumulation plants and research on the mechanism of selenium enrichment and tolerance are hotspot of selenium research.Cardamine hupingshanensis is a kind of selenium-hyperaccumulation plants that were found in hupingshan of Hunan province and yutangba of Enhsi city.As the fact that it's a newly discovered plant,there are still disputes about its name,the research on its genetic background is not deep enough and the lack of product research and development theory foundation,we did the molecular phylogenetic analysis,determined the selenium tolerance ability and studied the selenium accumulation dynamics as well as the general physiological changes with the selenium treatment.We got its partial genetic information by transcriptome sequencing and studied the change of transcriptome and proteome under different selenium environment.Finally,we got the following results:1.The 11 plant samples from Wuling mountain area belong to 3 species.The samples from yutangba and lianteiwan of Shanghe village of Xingtang township of Enshi city,diaoshiuya in Bengjiazi natural reserve of Changyang county,huangjiahe of Liziping village of Wufeng town of Wufeng,Dadongping village in Hupingshan national nature reserve of Shimen of Hunan province,zhushan,tangjiaping and zengjia of Waduanshan village of Chunmuying township of Xuanen county were the same species,and they are proved to be a new species-C.hupingshanensis.2.The maximal tolerate concentration of selenium in C.hupingshanensis seedlings was 80000 ?g.L-1,and the accumulation of selenium in C.hupingshanensis increased rapidly within 8-24 hours.24 hours later,the accumulation of selenium continued to be increased but the increase rate slowed down,which were not reach the degree of poisoning after 96 hours.The content of soluble protein,polysaccharide and total free amino acid reach to the top after a week when the treatment concentration were at 60,000? g.L-1,while the content decreased rapidly when treatment concentration exceed 80,000?g.L-1.The main form of selenium in C.hupingshanensis is selenocystine(SeCys2)which increased significantly at the concentration of 80,000 ? g.L-1.3.5.2 Gb and 4.8 Gb sequence data were generated from the Chupingshanensis leaves and roots respectively,After assemble,48989 and 78471 genes weregot in leaves and roots respectively.The average content of GC was 41.18%.Acquiring the Sequence Read Archive(SRA)number SRP097726 inNCBI.In addition,26273 and 23357 peptides were identified by using isobaric tags for relative and absolute quantitation(iTRAQ)quantitative techniques in the root and leaves,in which had 59 and 81 selenium containing peptide separately,and 5 of them both expressed in the roots and leaves.The transcriptome and proteome correlation analysis demonstrated that 4 genes co-expressed up-regulated,1 gene co-expressed down regulated,5 genes expressed the opposite,and 10 metabolic pathways responsed to selenium in common.4.The analysis of gene and protein expression variance demonstrated that selenium existed in the form of selenium,selenide,selenite in the biological molecules of C.hupingshanensis,which were the same with the results of RT-qPCR and RNA Seq.In the conditions of selenium treatment,the expression of SUL1A gene significantly increased illustrated that selenide was a an important mechanism of plant tolerance to selenium;the expression of Aat and PLR1 gene increased indicated that the transamination of selenocysteine and its derivatives was an important mechanism of plant tolerance to selenium;The up regulation of E2,E3,VHA-a2,CTP and CPI may explained the mechanism of selenuim tolerance,for the misfolded and malformed seleprotein can be degraded by the ubiquitin-proteasome and lysosomal degradation pathway,and the cysteine proteinase and cysteine protease inhibitor both rose,which may guarantee the stability of selenoprotein together.In addition,the expression of GST12,GST-u4 were both up-regulation in the root,and the same of ABCC1 and ABCC2,which may illustrate that the function of vacuolar storage had also played an important role in the selenium tolerance.