Arabidopsis TPPF Gene And Analysis Of Drought Resistance Mechanism

Trehalose is a non-reducing disaccharide composed of two glucose molecules connected by a glucosidic bond.Its physicochemical properties make it a special kind of sugar molecule.Compared with other sugars,it has high stability,strong hygroscopicity and a certain degree of corrosion resistance.Trehalose-6-phosphate synthase(TPS)catalyzes UDP-glucose and glucose-6-phosphate to form into 6-phosphate trehalose,which will be further dephosphorylated by trehalose-6-phosphate phosphatase.(Trehalose-6-phosphate Phosphatase,TPP)to trehalose.The Arabidopsis TPP gene family consists of 10 members.Previous studies have found that transforming rice TPP1 gene into maize can significantly increase corn yield and improving drought resistance.In this study,we found that TPP1 gene in rice is highly homologous with TPPF in Arabidopsis thaliana through the bioinformatics analysis.We cloned the gene and transfected Arabidopsis thaliana to obtain a highly expressed transgene homozygous lines called TPPF-OE lines.As for the homozygous lines,we verified the drought resistance phenotype using the soil drought experiment,and explored the possible regulating mechanism of TPPF gene with the fluorescent quantitative experiment of stress-related marker genes,hoping to provide the basis for molecular breeding of crops.(1)In this experiment,Arabidopsis thaliana TPPF gene was over-expressed.Soil drought experiment and detached leaves loss rate experiment showed that over-expression of TPPF could significantly improve the drought resistance of the plant although there was no significant difference on the detached leaves loss experiment between the wild-type and the TPPF-OE plants.(2)TPPF-OE plants has lower ion permeability under drought conditions.At the same time,the content of trehalose in the plant was also tested.Over-expression of TPPF has a higher trehalose concentration,indicating that overexpression of TPPF gene can increase the trehalose content in the plant,thereby regulating the osmotic pressure inside and outside the cell and protecting the integrity of the cell membrane,reducing drought damage on plant cells and improving plant drought resistance.(3)By qRT-PCR experiments with marker genes,we have screened that DREB1A may be an upstream regulatory gene of Arabidopsis thaliana TPPF.The bioinformatics analysis of 2kb upstream of the TPPF gene revealed that there is a DREB1A-specific core sequence within the 2kb region,further demonstrating that DREB1A is an upstream regulator of TPPF,which will need further experiments to confirm.Intrestingly,the DREB1A gene pathway is involved in non-ABA-dependent drought response pathway,which corroborates the above-mentioned results of the detached leaves loss rate experiment.