Plant Biotechnology
Online ISSN : 1347-6114
Print ISSN : 1342-4580
ISSN-L : 1342-4580
Original Paper
A novel strategy for promoting homoplasmic plastid transformant production using the barnase–barstar system
Ayako Okuzaki Mai TsudaKen-ichi KonagayaYutaka Tabei
ジャーナル フリー

2020 年 37 巻 2 号 p. 223-232


Plastid transformants form biofactories that are able to produce extra proteins in plastids when they are in a homoplasmic state. To date, plastid transformation has been reported in about twenty plant species; however, the production of homoplasmic plastid transformants is not always successful or easy. Heteroplasmic plants that contain wild-type plastids produce fewer target proteins and do not always successfully transfer transgenes to progeny. In order to promote the generation of homoplasmic plants, we developed a novel system using barnase–barster to eliminate wild-type plastids from heteroplasmic cells systematically. In this system, a chemically inducible cytotoxic barnase under a plastid transit signal was introduced into nuclear DNA and barster, which inhibits barnase, was integrated into plastid DNA with the primary selection markers aminoglycoside 3′-adenylyltransferase (aadA) and green fluorescence protein (GFP) gene. As expected, the expression of the plastid barnase was lethal to cells as seen in leaf segments, but barster expression in plastids rescued them. We then investigated the regeneration frequency of homoplasmic shoots from heteroplasmic leaf segments with or without barnase expression. The regeneration frequency of homoplasmic-like shoots expressing barnase–barster system was higher than that of shoots not expressing this. We expect that the application of this novel strategy for transformation of plastids will be supportive to generate homoplasmic plastid transformants in other plant species.

© 2020 The Japanese Society for Plant Cell and Molecular Biology
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