Functional Analysis Of The High-affinity Potassium Transporter Gene ZmHAK1in Maize

Potassium must be a large amount of mineral elements, played an important rolein the physiological function of plant. So far, K+in the soil which could be directlyabsorbed and utilized by plant was few, and the problem of potassium content in soilwas also much more serious. K+was absorbed by the low affinity absorption systemand high affinity absorption system, which could be named potassium channel and thehigh-affinity potassium transporter. Under the condition of low potassium, plantsabsorbed exogenous potassium ion by the high affinity potassium transporterFunctional analysis of the high-affinity potassium transporter gene ZmHAK1washelpful to improve absorbtion of potassium ion and adaption to low potassium inmaize, so that these could increase crop yields and to improve plant resistance to lowpotassium features.In this study, Bioinformatical analysis showed that this gene encoded a86.63KDprotein with771amino acids, it was a hydrophobic stable protein that the isoelectricpoint was8.63. This domain was predicted to located on the cell membrane with thefunction of the membrane protein. By sequence analysis showed that the protein washomology and conservative preferably with many other plants. This gene had ahighest homology to the high-affinity potassium from Sorghum bicolor, and the genehad a highly similar with the high-affinity potassium gene of the horse grass, reedsand rice. This result implied that this gene had a high resistance and responded to lowpotassium stress reaction under K+deficiency.The experimental bioinformatics analysis was a theoretical basis for thefunctional verification of the high-affinity potassium transporter gene ZmHAK1.Constructed expression vector of pCambia1301-ZmHAK1had transfered to theAgrobacterium tumefaciens EHA105. The transgenic Arabidopsis had acquired byinfectd Arabidopsis with Agrobacterium. The transgenic Arabiodopsises were screened preliminarily with a certain concentration of glufosinate. Then the screenedseedings were validated by PCR of the target gene and bar gene. T3Arabidopsiseswere obtained that was stability with T1transgenic Arabidopsises breeding. T3transgenic Arabidopsises could be stably inherited and had been obtained by themethod of Basta screening and Bar gene and the target gene PCR validation.Based on the analysis of the gene bioinformatics, the function of this gene wouldbe verified by using the T3generation of Arabidopsises. The transgenic Arabidopsiseswere able to adapt to the condition of low potassium stress by the comparison of somephysiological and biochemical parameters in T3transgenic Arabidopsises andwildtype. These parameters included germination rate, root elongation and potassiumuptake and MDA, and index determination of SOD, POD and CAT. By comparativeanalysis of germination under high salt conditions, we had found that transgenicArabidopsises had higher resistance than wildtype.On the whole, according to bioinformatics analysis of the high-affinity potassiumtransporter gene ZmHAK1and function prediction.This results revealed that the geneof ZmHAK1belonged to the family of high-affinity potassium transporter, andoverexpression of this gene could absorb external potassium in hypokalemiaconditions, and responsed to low potassium stress in transgenic Arabidopsis,...