Bioinformatics And Expression Analysis Of Apple MdGLRs Family Genes

In this paper, MdGLRs genes and their coding proteins were briefly investigated usingbioinformatics methods. We analyzed the expression of genes in response to chilling injury.MdGLRs were predicted based on apple genomic database. It is necessary to characterize theirfunctions in plant physiological and metabolistic processes. The preliminary researches in thispaper established the foundation for cloning MdGLRs genes and identifying their biologicalfunctions. The main research results were shown as follows:1. We blasted the apple genome database based on the sequences of Arabidopsis AtGLRsand as a result got32apple MdGLRs. They are similar to AtGLRs both in nucleic acid andamino acid sequences. All apple MdGLRs were divided into three sub-families, i.e.Ⅰ,Ⅱ, Ⅲ.Finally, all members were numbered.2. Twenty-two MdGLRs contained6domains, i.e. S1, M1, M2, M3, S2and M4, whichare high conserved in Arabidopsis. MdGLR3.9, MdGLR3.11, MdGLR3.13and AtGLR2.6arelack of M2domain, while MdGLR2.2, MdGLR3.5, MdGLR3.13contain incomplete M3domain, which is similar to AtGLR2.4and AtGLR2.6. Meanwhile, MdGLR3.14does nothave M4domain.3. With SMART online software, it was predicted that all MdGLRs are membraneproteins, generally containing a internal PBPs domain which had exogenous glutamate-gatedion channels activity, and can bind exogenous glutamate to ion channels complex, then madesthe channels open and finally facilitates ion transport across the membrane. Using TMHMMServer v.2.0software, it was found that transmembrane domains are generally localizedbetween500and800amino acids, where are also rich in conserved functional domains.Using SOPMA software, it was predicted that the secondary structures of MdGLRs aremainly Alpha helix, random coil and extended strand. Using PSORT, it was predicted thatMdGLRs are mainly located in endoplasmic reticulum and plasma membranes.4. Genes in the same sub-family showed different expressions in root, stem and leaf.5. MdGLR1.4expressed in root, stem, leaf, fruit skin and fruit flesh. It expressed at thehighest level in leaf. Expression level in leaves was: mature leaves> young leaves>old leaves.6. Low temperature induced MdGLR1.4expression in root, stem and leaf. Combinationof low temperature and LaCl3treatment decreased MdGLR1.4expression in stem and leaf.Meanwhile, ABA treatment did not change the expression of MdGLR1.4.