Developmental regulation of the gibberellin biosynthetic gene GA1 in Arabidopsis thaliana.

Journal Article (Journal Article)

The GA1 gene of Arabidopsis thaliana encodes ent-kaurene synthase A (KSA), which catalyzes the first committed step in the biosynthetic pathway of the plant hormone gibberellin (GA). Its location in the GA biosynthetic pathway has led to speculation that KSA regulation is one of the controlling steps. However, because KSA activity is so low that it is only measurable in Arabidopsis siliques, GA1 promoter-GUS reporter gene fusions and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) were used to examine the expression pattern of GA1. The results from this study indicate that GA1 gene expression is highly regulated during growth and development, and it is restricted to specific cell types at the sites of expression. GA1 promoter activity is highest in rapidly growing tissues, e.g. shoot apicas, root tips, developing flowers and seeds. It is also active in the vascular tissue of some non-growing organs, such as expanded leaves, suggesting that these leaves may be a site of GA synthesis for transport to other organs. It was also found that the first one or two introns in the GA1 gene are required for proper expression. Because of the high degree of regulation, GA1 may act as a gatekeeper, controlling the flow of metabolites into the GA biosynthetic pathway, while the levels of specific bioactive GAs are controlled by other downstream steps.

Full Text

Duke Authors

Cited Authors

  • Silverstone, AL; Chang, C; Krol, E; Sun, TP

Published Date

  • July 1997

Published In

Volume / Issue

  • 12 / 1

Start / End Page

  • 9 - 19

PubMed ID

  • 9263448

Electronic International Standard Serial Number (EISSN)

  • 1365-313X

International Standard Serial Number (ISSN)

  • 0960-7412

Digital Object Identifier (DOI)

  • 10.1046/j.1365-313x.1997.12010009.x


  • eng