Evaluation Of Salt Tolerance Of TaRBOHF1s-RNAi Transgenic Wheat Plants

Wheat(Triticum aestivum L.)is an important food crop widely planted in northern China.Wheat will be subjected to all kinds of abiotic stresses during its growth period,among which high salt stress is the main environmental factor of wheat yield reduction in China.High salt stress not only seriously restricted wheat yield,but also limited the planting area of wheat.Studying the salt tolerance mechanisms of wheat is an effective way to solve this problem.Plant respiratory burst oxidase homologue(RBOH),also known as NADPH oxidase(NOX),is a key enzyme in the generation of reactive oxygen species(ROS)in plant cells.Excessive ROS will cause oxidative damage to plants,and the signal transduction involved by ROS is an important signal pathway in cells.Numerous studies have found that RBOH is mainly involved in the regulation of plant growth and development,biological stress and abiotic stress.In the previous study,we obtained TaRBOHF1s-RNAi transgenic wheat plants,which showed significantly increased tiller number and lower ROS content compared to Fielder control plants.In this study,we mainly systematically evaluated the salt tolerance of TaRBOHF1s-RNAi transgenic wheat,and the main results are as follows:(1)Compared with Fielder control plants,the germination rate of TaRBOHF1s-RNAi transgenic wheat was significantly improved,which indicated that the down-regulation of TaRBOHF1s gene expression level could improve the vigor of wheat seeds vigors.(2)Under the salt stress environment,the growth status of TaRBOHF1s-RNAi transgenic wheat was better than that of Fielder control plant at all stages,and the root length,plant height,effective tiller number were higher than that of Fielder control plant,which indicated that TaRBOHF1s-RNAi transgenic wheat plants had better salt tolerance.(3)Physiological indexes related to salt tolerance of wheat were determined.The results showed that TaRBOHF1s-RNAi transgenic wheat plants contained lower levels of ROS and malondialdehyde(MDA).In the determination of osmotic adjustment substance content,proline content and Na~+/K~+of TaRBOHF1s-RNAi transgenic wheat plants,the contents of soluble sugar,soluble protein and proline were higher than those of Fielder control plants,and the change of Na~+/K~+was lower than that of Fielder control plants.The results showed that TaRBOHF1s-RNAi transgenic wheat plants had stronger osmotic adjustment ability,lower oxidative damage and stronger photosynthesis under salt stress.(4)To further study the molecular mechanism of TaRBOHF1s gene stress resistance,the transcriptome data of axillary buds of TaRBOHF1s-RNAi transgenic wheat were analyzed.The results showed that the down-regulation of TaRBOHF1s gene expression caused the up-regulation of P5CS,CNGC,MYB and other stress-resistance related genes,thus improving the tolerance of wheat to salt stress.TaRBOHF1s-RNAi transgenic wheat has better salt tolerance than Fielder control wheat.This experiment provides reference for studying the role and application of TaRBOHF1s gene in plant stress resistance,improving salt-tolerant varieties is of great significance.