The development of a plant leaf is a meticulously orchestrated sequence of events producing a complex organ comprising diverse cell types. The reticulate class of leaf variegation mutants displays contrasting pigmenta...The development of a plant leaf is a meticulously orchestrated sequence of events producing a complex organ comprising diverse cell types. The reticulate class of leaf variegation mutants displays contrasting pigmentation between veins and interveinal regions due to specific aberrations in the development of mesophyll cells. Thus, the reticulate mutants offer a potent tool to investigate cell-type-specific developmental processes. The discovery that most mutants are affected in plastid-localized, metabolic pathways that are strongly expressed in vasculature-associated tis- sues implicates a crucial role for the bundle sheath and their chloroplasts in proper development of the mesophyll cells. Here, we review the reticulate mutants and their phenotypic characteristics, with a focus on those in Arabidopsis thali- ana. Two alternative models have been put forward to explain the relationship between plastid metabolism and meso- phyll cell development, which we call here the supply and the signaling hypotheses. We critically assess these proposed models and discuss their implications for leaf development and bundle sheath function in C3 species. The characteriza- tion of the reticulate mutants supports the significance of plastid retrograde signaling in cell development and highlights the significance of the bundle sheath in C3 photosynthesis.展开更多
The Primacy question addressed in our study is: Is the difterntial expression of rbcL gene in mesophyll cells and in bundle sheath cells related to the sequence of the gene per se?An enzymatic approach was fist establ...The Primacy question addressed in our study is: Is the difterntial expression of rbcL gene in mesophyll cells and in bundle sheath cells related to the sequence of the gene per se?An enzymatic approach was fist established to separate the two groups of cells. Microscopic examination revealed satisfactory separation effect: minimal mutual contamination was found so that no mistake might be introduced into biochemical or molecular biological expeitments using such preparations. CpDNA were isolated from mesophyll cells and from bundle sheath cells and coding region of rbcL gene was obtained from each by PCR ampilfication.Cloning and sequencing were then done on them.Compartive analysis , however, revealed identical sequence, with a length of 1,368 bp, encoding 456 amino acids. Since sequences of the non-coding regions of rbcL gene in masephyll sad bundle sheath have not been obtained, it can not yet be concluded that the differential expression is not related to the sequence itself. Nevertheless,It sesems justifiable to infer that whatever difference there may be between the sequences of rbcL gene in two groups of cells can only be found in the non-coding regions(including promoter and the 3' down stream region).展开更多
文摘The development of a plant leaf is a meticulously orchestrated sequence of events producing a complex organ comprising diverse cell types. The reticulate class of leaf variegation mutants displays contrasting pigmentation between veins and interveinal regions due to specific aberrations in the development of mesophyll cells. Thus, the reticulate mutants offer a potent tool to investigate cell-type-specific developmental processes. The discovery that most mutants are affected in plastid-localized, metabolic pathways that are strongly expressed in vasculature-associated tis- sues implicates a crucial role for the bundle sheath and their chloroplasts in proper development of the mesophyll cells. Here, we review the reticulate mutants and their phenotypic characteristics, with a focus on those in Arabidopsis thali- ana. Two alternative models have been put forward to explain the relationship between plastid metabolism and meso- phyll cell development, which we call here the supply and the signaling hypotheses. We critically assess these proposed models and discuss their implications for leaf development and bundle sheath function in C3 species. The characteriza- tion of the reticulate mutants supports the significance of plastid retrograde signaling in cell development and highlights the significance of the bundle sheath in C3 photosynthesis.
文摘The Primacy question addressed in our study is: Is the difterntial expression of rbcL gene in mesophyll cells and in bundle sheath cells related to the sequence of the gene per se?An enzymatic approach was fist established to separate the two groups of cells. Microscopic examination revealed satisfactory separation effect: minimal mutual contamination was found so that no mistake might be introduced into biochemical or molecular biological expeitments using such preparations. CpDNA were isolated from mesophyll cells and from bundle sheath cells and coding region of rbcL gene was obtained from each by PCR ampilfication.Cloning and sequencing were then done on them.Compartive analysis , however, revealed identical sequence, with a length of 1,368 bp, encoding 456 amino acids. Since sequences of the non-coding regions of rbcL gene in masephyll sad bundle sheath have not been obtained, it can not yet be concluded that the differential expression is not related to the sequence itself. Nevertheless,It sesems justifiable to infer that whatever difference there may be between the sequences of rbcL gene in two groups of cells can only be found in the non-coding regions(including promoter and the 3' down stream region).
