Identification Of BpANN Genes Family And Function Analysis Of Salinity Tolerance In Betula Platyphylla

The Ca²⁺-dependent membrane-bound protein ANN is essential for many aspects of life,including oxidative activity,stress reaction,and plant development.To investigate the functions of ANN proteins in the woody plant Betula platyphylla（Betula platyphylla Suk）,In this study identified BpANNs genes in the genome by bioinformatics,analyzed the structural characteristics and expression properties of their family members,and investigated the role of Bp ANN1,Bp ANN2,Bp ANN3,and Bp ANN5 genes in saline and alkaline stress.The research result as follows:（1）A total of 10 Bp ANN genes,named Bp ANN1～10,were identified in the whole genome of Betula,and multiple sequence alignments revealed the presence of four repetitive ANN structural domains with type II Ca²⁺binding sites,F-actin binding sites and GTP binding motifs.10 genes were distributed on five chromosomes,and cis-activities related to stress response,phytohormone and light response were present in the promoter region.The phylogenetic analysis showed that the BpANNs genes were closely related to the Pt ANNs genes in Populus trichocarpa.（2）The expression of Bp ANN1～10 genes was analyzed,and 10 genes were tissue-specific,among which 7 genes were more expressed in leaves than in roots and stems,and the expression increased in roots,stems and leaves after induction by 4℃,37℃,drought,Na Cl and Na HCO₃.（3）The CDS of four genes,Bp ANN1,Bp ANN2,Bp ANN3,and Bp ANN5,with full lengths of 951,951,957,and 954 bp,encoding 316,316,318,and 317 amino acids,respectively,were cloned.The construction of overexpression recombinant vectors and fusion expression vectors for subcellular localization was successful.The fusion expression vectors were injected into the inner epidermis of onions using vacuum infiltration,and fluorescence microscopy revealed that all four genes were localized in the cell membrane.（4）The overexpression recombinant vectors of Bp ANN1,Bp ANN2,Bp ANN3,and Bp ANN5 genes were transferred into Agrobacterium,and transgenic plants were obtained by the genetic transformation of birch conidia embryos,and the transformation efficiency of the four genes in conidia embryos ranged from 5.33%to 8.28%.4,5,6,and 3 overexpression（OE）birch strains were obtained by genomic DNA and q RT-RCR.（5）In terms of growth and development,OE plants significantly outgrew the control in terms of plant fresh weight and root development.Malondialdehyde content was assessed after salt and alkali stresses were applied to WT and OE birch,respectively,and phenotypic alterations were noticed.The OE plants grew well under stress and had considerably less MDA content than the control,whereas the control leaves turned yellow and even wilted and fell off,showing that BpANNs genes are involved in plant growth and development as well as response to salt and alkali stresses.