Os04g0682800
AM1 encoded a putative KEA in chloroplast[1].
Contents
Annotated Information
Function
- KEAs were involved in chloroplast development and played important roles in drought tolerance. Mutation of the AM1 gene causes an albino midrib phenotype and enhances tolerance to drought in rice[1].
- AM1 functioned at the plastid membrane to control K+/H+ exchange. AM1 played an important role in chloroplast development in rice leaves. It also played an important role in regulating the expression of genes associated with chlorophyll biosynthesis, chloroplast development, and photosynthesis in the first few seedling leaves. Am1 show enhanced sensitivity to KCL at germination[1].
GO assignment(s): GO:0006812,GO:0006813, GO:0006885, GO:0008324, GO:0015299, GO:0016021
Mutation
am1 mutants[1]:
- Sheng et al. isolated a rice mutant, albino midrib 1 (am1). In the paddy filed, the am1 mutant displayed green- and white-variegation in the first few leaves, and the variegation appeared to be randomly distributed on the surface of the mutant leaves and predominantly near the leaf margins.
- Chloroplast gene expression and proteins accumulation were affected during chlorophyll biosynthesis and photosynthesis in am1 mutants.
- Accumulation of H2O2 in am1 mutants probably underlied the increased stomatal closure conferring the drought tolerance. The accumulation of most photosynthetic proteins was affected in am1 mutants due to defective chloroplast development.
Expression
- AM1 was most highly expressed in the L3 section at the early chloroplast and leaf development stage. AM1 was highly expressed in leaves, while lowly in roots[1].
- AM1 was induced by salt and PEG, and am1 showed enhanced sensitivity to salinity in seed germination and increased tolerance to drought[1].
Subcellular localization
Green fluorescent signals of AM1-GFP colocalized with the autofluorescent signals of chlorophyll indicating that AM1 targeted the rice chloroplasts[1].
Evolution
- AM1 contained twenty exons and nineteen introns. The open reading frame (ORF) of AM1 encodes a polypeptide of 1,155 amino acids with a calculated molecular mass of approximately 123 KD. Analysis of the AM1 protein sequence by ChloroP suggested a 41 amino acid chloroplast transit peptide (CTP) in the N-terminus[1].
- AM1 was grouped into the KEAIa family[2]. AM1 shares very high peptide identity (65%, 68%) and similarity (76%, 78%) with both of KEA proteins. Phylogenetic tree analysis showed that AM1 homologs were well differentiated and exhibited a clear evolutionary linkage from unicellular green algae to angiosperms[1].
Knowledge Extension
- KEA family remained relatively constant at 3–7 genes from unicellular algae to flowering plants suggesting conserved roles and its functions are largely unknown. The KEA family was categorized into three types: KEAIa, KEAIb and KEAII[2].
- KEAIa and KEAIb contain a C-terminal KTN domain which is lost in the KEAII. Clades Ia and Ib can be distinguished by its N-terminal domain. Clades Ia has a long hydrophilic N-terminal domain of about 570–770 amino acids, while clades Ib does not have and its C-terminus is slightly longer than the other sequence[1].
Labs working on this gene
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- National Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 Sheng P, Tan J, Jin M, et al. Albino midrib 1, encoding a putative potassium efflux antiporter, affects chloroplast development and drought tolerance in rice[J]. Plant cell reports, 2014, 33(9): 1581-1594.
- ↑ 2.0 2.1 Chanroj S, Wang G, Venema K, et al. Conserved and diversified gene families of monovalent cation/H+ antiporters from algae to flowering plants[J]. Frontiers in plant science, 2012, 3.
