Generation and properties of ascorbic acid-deficient transgenic tobacco cells expressing antisense RNA for L-galactono-1,4-lactone dehydrogenase

Citation
K. Tabata et al., Generation and properties of ascorbic acid-deficient transgenic tobacco cells expressing antisense RNA for L-galactono-1,4-lactone dehydrogenase, PLANT J, 27(2), 2001, pp. 139-148
Citations number
42
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Plant Sciences","Animal & Plant Sciences
Journal title
PLANT JOURNAL
ISSN journal
0960-7412 → ACNP
Volume
27
Issue
2
Year of publication
2001
Pages
139 - 148
Database
ISI
SICI code
0960-7412(200107)27:2<139:GAPOAA>2.0.ZU;2-I
Abstract
In higher plants, the terminal step Of L-ascorbic acid (AsA) biosynthesis i s catalyzed by the enzyme L-galactono-1,4-lactone dehydrogenase (EC 1.3.2.3 , GalLDH). We generated AsA-deficient transgenic tobacco BY-2 cell lines by antisense expression of the GalLDH cDNA that was amplified from BY-2 cells using PCR. Two transgenic cell-lines, AS1-1 and AS2-2, having a marked exp ression of antisense RNA were analyzed. Antisense suppression of GalLDH mRN A led to a significant decline in the GalLDH activity. The AsA levels in th e transgenic cell lines were found to be 30% lower than the wild-type BY-2 cells. In synchronous cultures, division of AS1-1 and AS2-2 cells was restr ained with a concomitant decrease in mitotic index that was probably due to a decline in AsA levels. The rate of cell growth was also found to be less than that of the wild-type cells. Interestingly, there was a significant p henotypic difference between the transgenic and wild-type cells. The calli of AS1-1 and AS2-2 appeared to be sticky and soft. Back extrusion method al so showed that AsA-deficient BY-2 callus was rheologically oft. Furthermore , microscopic analysis revealed that AS1-1 and AS2-2 cells were abnormally slender, suggesting a potential for a significant and a uni-axial elongatio n. Thus, we observed that decline in the AsA levels has an adverse effect o n the division, growth and structure of a plant cell.