Changes in Primary and Secondary Metabolite Levels in Response to Gene Targeting-Mediated Site-Directed Mutagenesis of the Anthranilate Synthase Gene in Rice

Metabolites

Hiroaki Saika²  Akira Oikawa¹  Ryo Nakabayashi¹  Fumio Matsuda¹  Kazuki Saito¹ 

[1] Riken Plant Science Center, Yokohama, Kanagawa 230-0045, Japan; E-Mails:;Plant Genome Engineering Research Unit, Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan; E-Mail:

关键词: gene targeting;    indole alkaloid;    metabolic engineering;    rice;    tryptophan;   

DOI  :  10.3390/metabo2041123

来源: mdpi

【 摘 要 】

Gene targeting (GT) via homologous recombination allows precise modification of a target gene of interest. In a previous study, we successfully used GT to produce rice plants accumulating high levels of free tryptophan (Trp) in mature seeds and young leaves via targeted modification of a gene encoding anthranilate synthase—a key enzyme of Trp biosynthesis. Here, we performed metabolome analysis in the leaves and mature seeds of GT plants. Of 72 metabolites detected in both organs, a total of 13, including Trp, involved in amino acid metabolism, accumulated to levels >1.5-fold higher than controls in both leaves and mature seeds of GT plants. Surprisingly, the contents of certain metabolites valuable for both humans and livestock, such as γ-aminobutyric acid and vitamin B, were significantly increased in mature seeds of GT plants. Moreover, untargeted analysis using LC-MS revealed that secondary metabolites, including an indole alkaloid, 2-[2-hydroxy-3-β-D-glucopyranosyloxy-1-(1H-indol-3-yl)propyl] tryptophan, also accumulate to higher levels in GT plants. Some of these metabolite changes in plants produced via GT are similar to those observed in plants over expressing mutated genes, thus demonstrating that in vivo protein engineering via GT can be an effective approach to metabolic engineering in crops.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.