Functional Analysis Of E3 Ubiquitin Ligase SINA Gene In Growth And Development And Drought Stress Of Soybean

Soybean,as an important grain and oil crop,plays an irreplaceable role in the national life.However,soybean production in our country can not satisfy its own demand by far.Atthe same time,the domestic and even the world’s arable land drought has greatly affected the soybean yield.In order to change this situation,high yield breeding of soybean and related work to increase soybean yield are becoming more and more important without affecting the proportion of domestic crop land.The key to solve this problem is to select high-yield and drought-tolerant genes and apply them to soybean breeding.SINA(SEVEN IN Absentia)is a typical member of the Ring-type E3 ubiquitin ligase subfamily of the TRAF(tumor necrosis factor-related factor)protein family.They play an important role in plant growth,development,and stress response.However,their role in soybean growth,development,and stress response remains unclear.In this study,we expressed AtSINA2 in the constitutive form of soybean.Through phenotype observation,seedling drought experiment and field planting experiment,we found that compared to wild type,transgenic soybean produced greater shoot biomass and grain yield,and showed improved seed oil and drought tolerance.Physiological analyses exhibited that the increased drought tolerance of transgenic plants was accompanied with a higher chlorophyll content,and a lower malondialdehyde accumulation and water loss during drought stress.Further transcriptomic analysis showed that AtSINA2 expression up-regulated the expressions of endogenous E3 ubiquitin ligase GmSINA5,blue light signaling pathway related genes and stress stress-related genes.In order to explore the response of endogenous SINA gene to drought and yield in soybean,12 endogenous GmSINAs genes were screened based on transcriptomic analysis results.Phylogenetic tree analysis showed that different SINA genes were distributed in different subgroups,suggesting different gene functions.Tissue expression pattern analysis of 9 GmSINAs clones showed that these genes were expressed in roots,stems,leaves,flowers and pods in response to 15% PEG treatment,and the expression gradient of GmSINA5 increased in the early stage of stress.Transcriptome analysis also showed that GmSINA5 was not only affected by AtSINA2,but also responded to drought stress.The upstream promoter elements of GmSINA5 were analyzed and found to contain ABA response elements and dehydration response elements.The results of yeast dihybrid experiment showed that GmSINA5 could form homologous dimers,or heterodimers with GmSINA1,GmSINA2,GmSINA3 and GmSINA9.The expression of GmSINA5 in Arabidopsis thaliana delayed the flowering stage and improved the resistance to osmotic stress.The root length and biomass of the transgenic Arabidopsis thaliana were higher than those of the control under osmotic stress.In conclusion,E3 ubiquitin ligase AtSINA2 gene can improve drought resistance and yield of soybean.We have obtained a new strain of transgenic soybean with drought tolerance and high yield.The preliminary study of endogenous GmSINA5 gene in soybean showed that it could regulate the flowering period and respond to osmotic stress,and could be used as a candidate gene in soybean resistance breeding.