Use of 4-methylindole or 7-methyl-DL-tryptophan in a Transformant Selection System Based on the Feedback-insensitive Anthranilate Synthase Alpha-subunit of Tobacco (ASA2)

Overview

Journal Plant Cell Rep

Publisher Springer

Date 2007 Dec 7

PMID 18060408

Citations 2

Authors

P Barone

Jack M Widholm

Affiliations

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Abstract

Effective selectable markers are needed for basic research and commercial applications that do not involve antibiotic or herbicide resistance. A novel selection system based on a feedback-insensitive anthranilate synthase alpha-subunit of tobacco (ASA2) as selectable marker using either 4-methylindole (4MI) or 7-methyl-DL-tryptophan (7MT) as the selection agent was developed. We found that these two components were able to discriminate better between ASA2 expressing and untransformed lines than the most commonly used analog 5-methyltryptopan (5MT) in the seedling growth inhibition test. We successfully integrated an expression cassette containing an ASA2 cDNA driven by a cauliflower mosaic virus 35S promoter into tobacco leaf discs by A. tumefaciens and selected transgenic plants on medium supplemented with 300 microM of 7MT or 4MI. Due to the expression of the feedback-insensitive ASA2, the transgenic lines produced showed higher free tryptophan (Trp) concentrations than the untransformed WT control. These results demonstrate the feasibility of the selection system with the ASA2 gene in combination with the use of Trp or indole analogs as selective agent.

Citing Articles

Tobacco plastid transformation using the feedback-insensitive anthranilate synthase [alpha]-subunit of tobacco (ASA2) as a new selectable marker.

Barone P, Zhang X, Widholm J J Exp Bot. 2009; 60(11):3195-202.

PMID: 19553372 PMC: 2718221. DOI: 10.1093/jxb/erp160.

Tissue culture specificity of the tobacco ASA2 promoter driving hpt as a selectable marker for soybean transformation selection.

Zernova O, Zhong W, Zhang X, Widholm J Plant Cell Rep. 2008; 27(11):1705-11.

PMID: 18679686 DOI: 10.1007/s00299-008-0589-7.

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