Modifying fatty acid profiles through a new cytokinin‐based plastid transformation system. (13th November 2014)

• Record Type: Journal Article
• Authors: Dunne, Aisling; Maple‐Grødem, Jodi; Gargano, Daniela; Haslam, Richard P.; Napier, Johnathan A.; Chua, Nam‐Hai; Russell, Rosalind; Møller, Simon Geir
• Is Part Of: Plant journal. Volume 80:Number 6(2014:Dec.)
• Page Start: 1131
• Page End: 1138
• Publication Date: 2014-11-13
• Subjects: Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.12684
• Languages: English
• ISSNs: 0960-7412

Abstract

<abstract abstract-type="main" id="tpj12684-abs-0001"> <title>Summary</title> <p>The widespread use of herbicides and antibiotics for selection of transgenic plants has not been very successful with regard to commercialization and public acceptance. Hence, alternative selection systems are required. In this study, we describe the use of <italic>ipt</italic>, the bacterial gene encoding the enzyme isopentenyl transferase from <italic>Agrobacterium tumefaciens</italic>, as a positive selectable marker for plastid transformation. A comparison between the traditional spectinomycin‐based <italic>aadA</italic> selection system and the <italic>ipt</italic> selection system demonstrated that selection of transplastomic plants on medium lacking cytokinin was as effective as selection on medium containing spectinomycin. Proof of principle was demonstrated by transformation of the <italic>kasIII</italic> gene encoding 3‐ketoacyl acyl carrier protein synthase III into tobacco plastids. Transplastomic tobacco plants were readily obtained using the <italic>ipt</italic> selection system, and were phenotypically normal despite over‐expression of isopentenyl transferase. Over‐expression of KASIII resulted in a significant increase in 16:0 fatty acid levels, and a significant decrease in the levels of 18:0 and 18:1 fatty acids. Our study demonstrates use of a novel positive plastid transformation system that may be used for selection of transplastomic plants without affecting the expression of transgenes within the integrated vector cassette or the resulting activity of the encoded protein. This system has the potential to be applied to monocots, which are typically not amenable to traditional antibiotic‐based selection systems, and may be used in combination with a negative selectable marker as part of a two‐step selection system to obtain homoplasmic plant lines.</p> </abstract>