Effects Of AcAPX On Root Morphology Establishment Of Arabidopsis Under Drought Stress

Vitamin C is also known as L-ascorbic acid(AsA).And it is biologically important to plants and animals.Studies have shown that AsA has been effectively used in plants to eliminate free radicals which produced in plants due to external environmental factors or autogenic respiration and photosynthesis,to ensure the internal balance of plants.Animals cannot synthesize AsA by themselves,so they need to absorb enough AsA from external sources to ensure their bodies keep nutrition balance.Ascorbate peroxidase(APX)also plays an important role in the AsA cycle in plants.Asa hemeprotein,it is distributed in different organelles and has a variety of isoenzymes in plants.It is the key enzyme for scavenging reactive oxygen species and the main antioxidant enzyme in the process of cell metabolism,as well as the main enzyme for AsA metabolism.At present,there are many researches on the scavenging of reactive oxygen species by APX,but few researches on the effect of APX on the growth and development of plant roots under abiotic stress conditions.Here,overexpressed AcAPX transgenic Arabidopsis thaliana plants(generation T₃)was used as the experimental material to observe the root phenotype,determined the AsA content in roots as well as he determination of the enzyme activity,and relative expression level of AcAPX was determined by real-time quantitative PCR.The main research results are as follows:1.There's no obvious difference of root hair number and length was observed on 1/2MS medium.However,on the 150 m M mannitol medium,through observation,AcAPX1,AcAPX2,AcAPX3,AcAPX4 strain,AcAPX5,AcAPX6 expression compared with WT per unit length(1mm)number of root hair and hair length increased significantly.2.q RT-PCR showed that the relative expression levels of overexpressed Arabidopsis thaliana lines AcAPX1,AcAPX2,AcAPX3,AcAPX4,AcAPX5 and AcAPX6 under drought stress were higher than those of the normal overexpressed Arabidopsis thaliana lines growing on 1/2MS medium.3.APX activity assay results showed that APX activity was significantly increased in the overexpressed strains under drought stress compared with the normal growth on 1/2MS medium.4.The AsA measurement results showed that there was no significant difference in the overall AsA content between the overexpressed lines and WT,but the ratio of reduced AsA to total AsA content in the overexpressed lines under drought stress was significantly decreased compared with that in the normal growth medium in 1/2MS,and the proportion of reduced AsA in the overexpressed lines was less than that in WT.In conclusion,Acorbate Peroxidase(AcAPX)has a positive regulation effect on root hair growth and development under drought stress.This study provides a new direction for the study of APX function in plants.