title: Identification and Characterization of a Chloroplast-Targeted Obg GTPase in Dendrobium officinale.
abstract: Bacterial homologous chloroplast-targeted Obg GTPases (ObgCs) belong to the plant-typical Obg group, which is involved in diverse physiological processes during chloroplast development. However, the evolutionarily conserved function of ObgC in plants remains elusive and requires further investigation. In this study, we identified DoObgC from an epiphytic plant Dendrobium officinale and demonstrated the characteristics of DoObgC. Sequence analysis indicated that DoObgC is highly conserved with other plant ObgCs, which contain the chloroplast transit peptide (cTP), Obg fold, G domain, and OCT regions. The C terminus of DoObgC lacking the chloroplast-targeting cTP region, DoObgCΔ1-160, showed strong similarity to ObgE and other bacterial Obgs. Overexpression of DoObgCΔ1-160in Escherichia coli caused slow cell growth and an increased number of elongated cells. This phenotype was consistent with the phenotype of cells overexpressing ObgE. Furthermore, the expression of recombinant DoObgCΔ1-160enhanced the cell persistence of E. coli to streptomycin. Results of transient expression assays revealed that DoObgC was localized to chloroplasts. Moreover, we demonstrated that DoObgC could rescue the embryotic lethal phenotype of the Arabidopsis obgc-t mutant, suggesting that DoObgC is a functional homolog to Arabidopsis AtObgC in D. officinale. Gene expression profiles showed that DoObgC was expressed in leaf-specific and light-dependent patterns and that DoObgC responded to wounding treatments. Our previous and present studies reveal that ObgC has an evolutionarily conserved role in ribosome biogenesis to adapt chloroplast development to the environment.
authors.affiliation: 1 Agronomy College, Sichuan Agricultural University , Chengdu, China .
authors.forename: Ji
authors.initials: J
authors.lastname: Chen
authors.affiliation: 1 Agronomy College, Sichuan Agricultural University , Chengdu, China .
authors.forename: Feng
authors.initials: F
authors.lastname: Deng
authors.affiliation: 1 Agronomy College, Sichuan Agricultural University , Chengdu, China .
authors.forename: Mengsheng
authors.initials: M
authors.lastname: Deng
authors.affiliation: 1 Agronomy College, Sichuan Agricultural University , Chengdu, China .
authors.forename: Jincheng
authors.initials: J
authors.lastname: Han
authors.affiliation: 1 Agronomy College, Sichuan Agricultural University , Chengdu, China .
authors.forename: Jianbin
authors.initials: J
authors.lastname: Chen
authors.affiliation: 1 Agronomy College, Sichuan Agricultural University , Chengdu, China .
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: 1 Agronomy College, Sichuan Agricultural University , Chengdu, China .
authors.forename: Shen
authors.initials: S
authors.lastname: Yan
authors.affiliation: 1 Agronomy College, Sichuan Agricultural University , Chengdu, China .
authors.forename: Kai
authors.initials: K
authors.lastname: Tong
authors.affiliation: 1 Agronomy College, Sichuan Agricultural University , Chengdu, China .
authors.forename: Fan
authors.initials: F
authors.lastname: Liu
authors.affiliation: 2 Institute for New Rural Development, Sichuan Agricultural University , Yaan, China .
authors.forename: Mengliang
authors.initials: M
authors.lastname: Tian
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D060365:Chloroplast Proteins / Q000235:genetics* / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D017124:Conserved Sequence; D031667:Dendrobium / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D000072417:Protein Domains; D017510:Protein Folding; D021382:Protein Sorting Signals / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D016415:Sequence Alignment; D013307:Streptomycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D060365:Chloroplast Proteins; D010940:Plant Proteins; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; C078737:chloroplast transit peptides; D020558:GTP Phosphohydrolases; D013307:Streptomycin
keywords: Arabidopsis thaliana; Dendrobium officinale; Obg; cell susceptibility; chloroplast