The Molecular Mechanism Underlying Functional Switch Of The Aquaporin PIP1;3 Between Transport Of Carbon Dioxide And Translocation Of Bacterial Type ? Effectors In Rice

Aquaporins are widely present on plant cell membranes and participate in plant growth,development and photosynthesis by transporting small molecules such as water and carbon dioxide.AQPs not only have previously unknown physiological functions,the substrate selectivity far exceeds the original concept of "water channel",but also affect the pathogenicity and resistance in the plant.At present,there are few studies on how aquaporins are involved in the pathogenicity of pathogens.Some studies have shown that the interaction of T3 translocator Hpal and OsPIP1;3 of Xoo helps the translocation of PthXo1 from bacteria to rice cells.PthXo1 increase the experssion of the OsSWEET11 gene in the host cell,and promotes sugar transport in favor of pathogen infection.Our lab have created OsPIP1;3-knockout(KO)and OsPIP1:3-overexpressing(OE)transgenic lines under background of the rice variety Nipponbare,and plant them in Taian and Haikou to show the effect on plant physiological functions.The result show that plant biomass gained 27.0%increase in OE lines and incurred 30.5%decrease in KO lines.Moreover,OsPIP1;3 overexpression conferred a fruitful trait on rice,allowing more grains to be produced.On average,grain weight gained 21.3%increase in OE lines and incurred 14.5%decrease in the KO lines.By measuring the net photosynthetic rate AN and mesophyll conductance gm of the leaves in WT,OE#8 and KO#9 plants growing in the field,it was found that AN in KO lines was reduced in average of 25%,and OE lines increased in average of 27%compared to WT.The gm increased by 25.56%on OE#8 and decreased by 21.50%on KO#9,which indicated that the photosynthetic function of OsPIP1;3 relies on its role in CO2 transport.I detected the translocation of effector PthXol,AN and gm within 0-96 hours after inoculation after each line were inoculated with PX099A and ?pthXo1/pthXo1-cya,OsPIP1;3 was found that function lossing transporting CO2 by infection in turn to mediates the translocon effector PthXo1 to rice cells,which increase expression of SWEET11 and induce bacterial toxicity and rice disease.In order to effectively control Xoo infection,we studied the T3 effector translocation interference.I construct hpal,hrpF knockout mutant and the results showed that the translocon of PthXo1 decreased significantly without hpa1 and hrpF gene.The prokaryotic expression of the transposon genes hpa1,hrpF and their functional domains,and interference recognition of rice interface receptors with phosphatidylinositol inhibitors.After inoculation with PXO99A and ?pthXo1/pthXo1-cya strains,it was found that the decreasing in effector translocon and reducing the length of the lesion,this result shows the application value of T3 effector translocation interference in the control of rice leaf blight.