In present paper, one of the T-DNA insertional embryonic lethal mutant of Arabidopsis is identifled and designated as acd mutant. The embryo development of this mutant is arrested in globular stage. The cell division ...In present paper, one of the T-DNA insertional embryonic lethal mutant of Arabidopsis is identifled and designated as acd mutant. The embryo development of this mutant is arrested in globular stage. The cell division pattern is abnormal during early embryogenesis and results in disturbed cellular differentiation. Most of mutant embryos are finally degenerated and aborted in globular stage. However, a few of them still can germinate in agar plate and produce seedlings with shorter hypocotyl and distorted shoot meristem. To understand the molecular basis of the phenotype of this mutant, the joint fragment of T-DNA/plant DNA is isolated by plasmid rescue and Dig-labeled as probe for cDNA library screening. According to the sequence analysis and similarity searching, a 936bp cDNA sequence (EMBL accession#: Y12555) from selected positive clone shows a 99.8 % (923/925bp) sequence homology with Alanyl-tRNA Synthetase (A1aRS) gene of Arabidopsis thaliana. Furthermore, the data of in sitll hybridization experiment indicate that the expression of AlaRS gene is weak in early embryogenesis and declines along with globular embryo ’development’ in this mutant.Accordingly, the reduced expression of AlaRS gene maybe closely related to the morphological changes in early embryogenesis of this lethal mutant.展开更多
文摘In present paper, one of the T-DNA insertional embryonic lethal mutant of Arabidopsis is identifled and designated as acd mutant. The embryo development of this mutant is arrested in globular stage. The cell division pattern is abnormal during early embryogenesis and results in disturbed cellular differentiation. Most of mutant embryos are finally degenerated and aborted in globular stage. However, a few of them still can germinate in agar plate and produce seedlings with shorter hypocotyl and distorted shoot meristem. To understand the molecular basis of the phenotype of this mutant, the joint fragment of T-DNA/plant DNA is isolated by plasmid rescue and Dig-labeled as probe for cDNA library screening. According to the sequence analysis and similarity searching, a 936bp cDNA sequence (EMBL accession#: Y12555) from selected positive clone shows a 99.8 % (923/925bp) sequence homology with Alanyl-tRNA Synthetase (A1aRS) gene of Arabidopsis thaliana. Furthermore, the data of in sitll hybridization experiment indicate that the expression of AlaRS gene is weak in early embryogenesis and declines along with globular embryo ’development’ in this mutant.Accordingly, the reduced expression of AlaRS gene maybe closely related to the morphological changes in early embryogenesis of this lethal mutant.
