Functional Analysis Of GmUPL1 And GmUPL2 In Soybean (Glycine Max )under Aluminum Stress

In acid soil,Aluminum toxicity is one of main limiting factors which can restrict the growing and production of crops.E3 Ubiquitin ligating enzymes have been reported to involve in various metabolic processes in plant cells.Their correlation with Al toxicity or Al resistnce process need to be further clarified..Our earlier transcriptional profile in soybean root apices under Al stress has revealed the upregulation of two E3 Ubiquitin ligating enzymes Glyma.10G156500 ?GmUPL1?and Glyma.13G072800 ?GmUPL2?.Present study aimed to examin the functions of GmUPL1 and GmUPL2 under Al stress by bioinformatics analysis,subcellular localization,expression pattern analysis,overexpression in soybean hairy roots and arabidopsis.GmUPL1 and GmUPL2 showed about 12%similariy.They highly conserved in the RING areas,but varied at other regions.Quantification real-time PCR showed that the transcription abudance of GmUPL1 and GmUPL2 increasedunder Al stress especially at 24 h.The expression of GmUPL2 was also increased under Cu²⁺or La³⁺stress.The expression of GmUPL1 was increased under Cu²⁺stress but not respond to La³⁺treatment.The vectors carrying CaMV 35S::GmUPL1:GFP and CaMV 35S::GmUPL2:GFPwas transiently transformed into arabidopsis protoplast and showed that both GmUPL1 and GmUPL2 located in cytoplasm.Genes will reduce the Al tolerance of transgenic soybean`s roots.Overexpressing GmUPL1 and GmUPL2 genes into soybean`s roots can not change the expression pattern of genes and the citric acid secretion rates of the roots are also no significant difference.With CaMV 35S as promoter,GmUPL2 was successfully transformed into Arabidopsis to produce the T3 homozyous lines?GmUPL2-OE?.GmUPL2-OE showed similar relative root elongation compared with the vector-transformed or col-4 arabidopsis.GmUPL2-OE also showed similar germination rates under mannitol stress or salt stress with the vector-transformed or col-4 arabidopsisGmUPL1 and GmUPL2 was respectively overexpressed in soybean hairy roots?GmUPL1-OE,GmUPL2-OE?with 35S as promoter.Their overexpression didn't change the expression pattern of Al resistance related genes such as GmAACT1?GmSTOP1?GmFRDL?GmME1 under+Al or-Al conditions.But,theheavier hematoxylin staining on GmUPL1-OE and GmUPL2-OE hairy roots showed suffered more Al toxicity.The mechanism that GmUPL1 and GmUPL2 in regulated Al toxicity in soybean need further clarifying.