Functional Analysis Of Arabidopsis LOH1 Gene In Embryogenesis And Postembryonic Development

Embryogenesis is the basis of plant growth development. People carried out researches on plant embryogenesis and identified genes function in this process. Some of the genes are involved in the early embryonic morphogenesis. These genes are associated with cell growth, metabolism, transport and transcriptional process.In this study, we identified a function unknown gene LOH1(LAG ONE HOMOLOGUE 1) from the transcriptome analysis of somatic enbryogenesis, which was highly expressed in the initiated somatic embryos (SEs) relative to the SE surronding tissues. We analyzed the phenotypes of LOH1 loss-of-fuction mutants to understand the function of LOH1 in embryogenesis and postembryonic development. The results were as follows:(1) The embryogenesis of lohl mutant was defective from early embryo development compared with the wild type plants.(2) The development of lohl mutant was slower than the wild type plants. The number of rosette leaves was reduced in vegetative growth. During reproductive development, flowering and senescence were later than wild type, lohl mutant displayed aberration in the configuration of both male and female gametes. The ratio of pollen germination was reduced in lohl mutant. Scanning electron microscopy showed that pollen had aberrant morphology. In addition, the female gametes were enlongated.(3) Mutations in the LOH1 gene caused abnormal development of shoot and root apical meristems. Shoot apical meristems of lohl mutants were significantly reduced in size. As well, the quiescent center cells in the root apical meristems had abnormal cell divisions.(4) Through analyzing the expression patterns of LOH1, we found that LOH1 expressed in various tissues, especially in the ovules, two-cell embryos, heart-shaped embryos, cotyledons, shoot apical meristem, root tip and pollen grains.(5) LOH1 protein was probably localized in the plastids and ribosomes. LOH1 may be involved in the chloroplast group ? intron splicing and chloroplast development.These results suggest that the loss-of-function LOH1 gene can lead to abnormal embryogenesis and postembryonic development. Further studies are required for understanding the biological function of LOH1 gene whether through chloroplast group ? intron splicing.