Proteomic Study On Response Of Maize Roots To Low Potassium Stress And Physiological Verification

Potassium uptake efficiency determines the ability of plants to take up K under low soil K availability.It is important to cultivate maize with higher K uptake efficiency.We focused on the low potassium tolerant mechanisms,with poassim-efficient maize（90-21-3）and potassium-inefficient maize（D937）as materials.The maize were treated with low potassium for 3 days at three leaf stages.And then,the biomass,characteristics of potassium nutrient response and the root proteome were compared analysis among the two maizes in response to low potassium stress.The following conclusions are drawn.1.GO analysis,KEGG pathway enrichment and protein interaction analysis of differential proteins between 90-21-3 and D937 under low potassium stress showed that the changes involved in the following pathways made 90-21-3 more resistant to low potassium than D937.（1）:Metabolism changes enhance the acclimation to low potassium stress in maize.Under low potassium stress,carbohydrates and amino acids in corn were continuously synthesized and metabolized,which can not only activate the potassium absorption and transport system but also achieve efficient utilization of potassium ions.（2）:Adapt to low potassium stress by decreasing reactive oxygen species in maize.Under low-potassium stress,differential proteins related to reactive oxygen species scavenging in K-efficient maize90-21-3 were increased significantly.It can prevent the cell from damage caused by reactive oxygen species in 90-21-3 in response to low potassiu stress.（3）:Improve maize tolerance to low potassium environment through low potassium-induced transcription and translation process.Proteins related to ribosomes were increased under low potassium stress.It can regulate cellular metabolism.In other hand,HEAT shock protein 90-5 were synthesized to cope with low potassium stress.2.Under low potassium stress,the relative electrical conductivity of potassium inefficient maize was significantly increased.Wihle the relative electrical conductivity of potassium effiienty maize has no singificnat difference under low potassium for 1 and 3 days as compred to the control.These results indicated that potassium effiienty maize can better maintain the interity of the plasma membrane under low potassium stress.The malondialdehyde content of both maize were increased increased in response to low potassium for 1 and 3 days,but with no significantly difference.Superoxide increased anion were significantly in both maize in response to low potassium.However,there was no significantly diffenrence between the two maize.The H₂O₂increased significantly in D937but not in potassium effiienty maize 90-21-3 in response to low potassium for 1 and 3 days.The activities of POX and CAT in D937 also showed higher than that of 90-21-3.