Journal Article

Arrested Differentiation of Proplastids into Chloroplasts in Variegated Leaves Characterized by Plastid Ultrastructure and Nucleoid Morphology

Wataru Sakamoto, Yasuyuki Uno, Quan Zhang, Eiko Miura, Yusuke Kato and Sodmergen

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 50, issue 12, pages 2069-2083
Published in print December 2009 | ISSN: 0032-0781
Published online September 2009 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pcp127
Arrested Differentiation of Proplastids into Chloroplasts in Variegated Leaves Characterized by Plastid Ultrastructure and Nucleoid Morphology

More Like This

Show all results sharing these subjects:

  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

Leaf variegation is seen in many ornamental plants and is often caused by a cell-lineage type formation of white sectors lacking functional chloroplasts. A mutant showing such leaf variegation is viable and is therefore suitable for studying chloroplast development. In this study, the formation of white sectors was temporally investigated in the Arabidopsis leaf-variegated mutant var2. Green sectors were found to emerge from white sectors after the formation of the first true leaf. Transmission electron microscopic examination of plastid ultrastructures confirmed that the peripheral zone in the var2 shoot meristem contained proplastids but lacked developing chloroplasts that were normally detected in wild type. These data suggest that chloroplast development proceeds very slowly in var2 variegated leaves. A notable feature in var2 is that the plastids in white sectors contain remarkable globular vacuolated membranes and prolamellar body-like structures. Although defective plastids were hardly observed in shoot meristems, they began to accumulate during early leaf development. Consistent with these observations, large plastid nucleoids detected in white sectors by DNA-specific fluorescent dyes were characteristic of those found in proplastids and were clearly distinguished from those in chloroplasts. These results strongly imply that in white sectors, differentiation of plastids into chloroplasts is arrested at the early stage of thylakoid development. Interestingly, large plastid nucleoids were detected in variegated sectors from species other than Arabidopsis. Thus, plastids in variegated leaves appear to share a common feature and represent a novel plastid type.

Keywords: Arabidopsis thaliana; Chloroplast development; Electron microscopy; Leaf variegation; Plastid nucleoid; Thylakoid membrane

Journal Article.  7097 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.