The T‐region of Ti plasmids codes for an enzyme synthesizing indole‐3‐acetic acid

Abstract

Gene 2 from the T region of Ti plasmids appears to be expressed both in eucaryotic and in procaryotic systems. In transformed plant cells it participates in auxin-controlled growth and differentiation, and in bacteria it is expressed into a defined protein of M, 49000. We investigated the possibility that it codes for an enzyme involved in auxin bi osynt hesis .Only extracts from Escherichia coli cells expressing gene 2 hydrolyzed indole-3-acetamide into a substance which was unambiguously identified as indole-3-acetic acid. The same reaction was found in Agrobacteria containing gene 2, but not in strains lacking the gene. Extracts from tobacco crown gall cells, but not from non-transformed cells, showed the same enzyme activity, and the reaction product was also identified as indole-3-acetic acid. The results indicate that gene 2 of the T region, which participates in tumorous growth of plant cells, codes both in bacteria and in plants for an amidohydrolase involved in the biosynthesis of the plant hormone indole-3-acetic acid.

The transfer of DNA from Agrobacterium tumefaciens into plants: a feast of fundamental insights

“…4. Novel pathways for plant hormone synthesis: T-DNA encoded genes for auxin and cytokinin biosynthesis responsible for tumor phenotype (Akiyoshi et al, 1984;Barry et al, 1984;Buchmann et al, 1985;Inze et al, 1984;Schro È der et al, 1984;Thomashow et al, 1984). 5.…”

Altered Growth and Wood Characteristics in Transgenic Hybrid Aspen Expressing Agrobacterium tumefaciens T-DNA Indoleacetic Acid-Biosynthetic Genes

“…The endogenous concentration of IAA can be altered by transforming plants with the Agrobacterium tumefaciens T-DNA IAA-biosynthetic genes iaaM and iaaH, encoding Trp-2-mono-oxygenase (Thomashow et al, 19 86;Van Onckelen et al, 1986) and indole-3-acetamide hydrolase (Schroder et al, 1984;Thomashow et al, 1984), respectively. These two enzymes catalyze a two-step biosynthesis of IAA from Trp via indole-3-acetamide.…”

Hormonal Characterization of Transgenic Tobacco Plants Expressing the rolC Gene of Agrobacterium rhizogenes TL-DNA

“…The iaaH and iaaM genes from Agrobacterium tumefaciens encode enzymes involved in the biosynthesis of IAA from tryptophan (Inzé et al, 1984;Schroder et al, 1984;Tomashow et al, 1984). The ipt gene product, also originating from A. tumefaciens, mediates the synthesizes of iPA-P from isopentenyl pyrophosphate and AMP (Akiyoshi et al, 1984;Bany et al, 1984), and the iaaL gene product from Pseudomonas savastanoi conjugates IAA to Lys (Glass et al, 1986;Hutzinger et al, 1986;Roberto et al, 1990).…”