Investigation On The Function Of AtZntB1 Gene In Arabidopsis

Magnesium is the fourth largest element in plant growth except for nitrogen,phosphorus,and potassium.It is the only metal element present in chlorophyll molecules.It is also an activator for many enzymes.It is involved in numerous physiological and biochemical reactions during plant growth and development.In order to investigate the relationship between Mg2+ transporter and AtZntB1 genes of Arabidopsis,we cloned the AtZntB1 gene and performed a preliminary identification of its function.First,we amplified the AtZntB1 gene from the entire gene sequence of Arabidopsis thaliana by ordinary PCR technology,and analyzed its gene sequence and corresponding amino acid sequence.Secondly,we analyzed the expression change of AtZntB1 gene in wild-type Arabidopsis under different conditions of magnesium deficiency and high magnesium induction.Next,We constructed the gene into yeast expression vector pAUR123 and bacterial expression vector pTrc99a,and transfer them into yeast ZHY3 and Salmonella typhimurium MM281,respectively.Based on two homozygous atzntb1 mutants and wild-type Arabidopsis thaliana,we analyzed the phenotypic,root length,and fresh weight of atzntb1 Arabidopsis mutant in 2.5 mM Mg2+ and the absence of different divalent metal ions(Ca2+、Fe2+、Zn2+、Mn2+、Mg2+)conditions,and low and high magnesium.Finally,we tested the expression of Marker genes(ACA13,ARD3,CAX3,WRKY46,CML37,NDB2,AtDTX3,AtDTX1,UGT72E4)associated with low magnesium response in wild-type and two atzntb1 mutant Arabidopsis under 0 mM and 2.5 mM Mg2+ treatment conditions.Through analysis,we draw the following five conclusions:1.AtZntB1 has a similar structure to CorA protein,with two transmembrane regions at the C-terminus,which may be related to Mg2+ transport.2AtZntB1 gene can be expressed in the aboveground and underground part of Arabidopsis thaliana at the same time,under the conditions of magnesium deficiency and high magnesium,its expression will increase or decrease accordingly,so we speculate that the expression of AtZntB1 gene will be affected by magnesium deficiency and high magnesium,it may be related to the Mg2+ stress response.3.AtZntB1 gene was not related to Zn2+transport,but related to Mg2+.4.The growth of the two atzntb1 mutant plants was weaker than that of the wild type under the conditions of lack of Ca2+,especially Mg2+.The same is true of growth under low and high magnesium conditions.5.Magnesium deficiency stress induced increased expression of marker genes associated with low magnesium response in two atzntb1 mutants.The above results preliminarily prove that AtZntB1 may have the function of Mg2+transport in Arabidopsis.