Functional Analysis Of A Maize Plasma Membrane Intrinsic Protein ZmPIP2;6 Associated With Water Stress

Maize（Zea mays L.）as an important food,feed and economic crop,plays a crucial role in agricultural production of China.Drought and salinity have been the severe abiotic stress affecting maize production,developing maize with drought and salt resistance continues to be an important objective of increasing maize production.Plasma membrane Intrinsic Proteins（PIPs）exist widely in the membrane system of plant cells,which are essential to water transport and stress response in plant.In our study,functional analysis of ZmPIP2;6 in plant water stress tolerance has been proceed.The results were as follow:1)Amino acid sequences and protein structure of ZmPIP2;6 were analyzed.ZmPIP2;6 shares the same conserved structural domains and a conserved sequence as the other PIPs involved in water stress tolerance.2)ZmPIP2;6-GFP infusion vector was constructed and assessed using maize protoplasts isolated from leaves of maize seedlings.The result indicated ZmPIP2;6 was localized on the plasma membrane.3)Expression pattern analysis showed that ZmPIP2;6 was high abundance in tassel,whereas it was lowly expressed in endosperm.Treatment with PEG or NaCl resulted in induced expression of ZmPIP2;6 in root and leaves in maize.4)ZmPIP2;6 overexpression transgenic Arabidopsis has been developed and showed higher tolerance compared with wildtype under osmotic,drought and salt stress conditions.The root length of ZmPIP2;6 overexpression transgenic Arabidopsis was longer than that of wildtype under osmotic or salt stress simulated by MS medium.In soil culture,compared with wildtype,drought tolerance of ZmPIP2;6 overexpression transgenic Arabidopsis was enhanced.5)The expressions of stress responsive genes were changed in ZmPIP2;6overexpression Arabidopsis under drought or salt condition.6)ZmPIP2;6 overexpression and crispr-cas9 transgenic maize have been generated and identified.7)In BiFC experiment,ZmPIP2;6 interacted with ZmPIP1;1 might lead to the subcellular relocalized on the plasma membrane and chloroplast.In conclusion,under osmotic or salt stress condition,the expression of ZmPIP2;6was up-regulated.Overexpression of ZmPIP2;6 in transgenic Arabidopsis would increase the tolerance of osmotic,salt and drought stress.The expressions of genes in the Arabidopsis stress signaling pathway would be impacted by ZmPIP2;6 under drought or salt stress.These results suggested that ZmPIP2;6 might be related to the responsive approaches of plant water stress.Further research on the ZmPIPs interaction and CO₂ permeability of ZmPIP2;6 in maize should be helpful in understanding PIPs functions in plants.