Effects Of The Effector Protein PIIN＿05330 Of The Endophytic Fungus Piriformospora Indica On Drought Resistance Of Arabidopsis Thaliana

Abiotic stress is a key constraint to global crop failure.Once plants are subjected to these abiotic stresses or combined stresses,the stability of plant membranes and cell homeostasis will be destroyed.Drought stress is a serious abiotic stress form determined by long-term water shortage.Therefore,unavailable or limited water supply minimizes productivity and yield,and restoration of drought resistance of crops has become a top priority for food security.In this paper,we cloned the PIIN＿05330 gene of Piriformospora indica to obtain transgenic Arabidopsis lines,and used medium and soil culture methods to create drought stress conditions to study the effect of PIIN＿05330 protein on the drought resistance of Arabidopsis.The main results are as follows:(1)In terms of growth and development,under drought stress,PIIN＿05330 gene is very sensitive during the Arabidopsis bud stage,and the germination rate is significantly reduced.The root surface area,root diameter,root volume and root length of the transgenic lines are higher than those of the control group.The relative root elongation and root tip number were significantly higher than WT and VT.In addition,under drought conditions,PIIN＿05330 protein has a positive regulatory effect on the aboveground biomass and chlorophyll content of Arabidopsis thaliana,which can maintain the relative water content of Arabidopsis thaliana,reduce the relative conductivity,and cannot compensate for the decrease in the number of fruit pods.(2)In terms of antioxidant system,the SOD,POD and CAT of Arabidopsis strains all increased to varying degrees under drought conditions.Among them,the transgenic plant lines performed better in terms of CAT activity,which was about twice that of the control group under drought conditions.Under drought stress,PIIN＿05330 protein can increase proline content,significantly increase soluble sugar and soluble protein content,and significantly reduce MDA content,indicating that it can effectively reduce plant damage and protect plant cell membrane system.In addition,the drought stress made the ASA and GSH content of the transgenic line significantly higher than the control group,and the hydrogen peroxide content was much lower than the control group.It shows that under drought stress conditions,PIIN＿05330 protein can effectively clean up the hydrogen peroxide produced during plant metabolism,maintain cell homeostasis,avoid plant oxidative damage,and improve the drought resistance of transgenic Arabidopsis.