Overexpression of a Gene Involved in Phytic Acid Biosynthesis Substantially Increases Phytic Acid and Total Phosphorus in Rice Seeds

Plants

Yusuke Tagashira²  Tomoe Shimizu²  Masanobu Miyamoto²  Sho Nishida²  Kaoru T. Yoshida¹  Francesca Sparvoli²  Roberto Pilu² 

[1] Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan;

关键词: ectopic expression;    mineral element;    molecular breeding;    Oryza sativa L.;    phosphorus;    phytic acid;    seed;    translocation;   

DOI  :  10.3390/plants4020196

来源: mdpi

【 摘 要 】

The manipulation of seed phosphorus is important for seedling growth and environmental P sustainability in agriculture. The mechanism of regulating P content in seed, however, is poorly understood. To study regulation of total P, we focused on phytic acid (inositol hexakisphosphate; InsP₆) biosynthesis-related genes, as InsP₆ is a major storage form of P in seeds. The rice (Oryza sativa L.) low phytic acid mutant lpa1-1 has been identified as a homolog of archael 2-phosphoglycerate kinase. The homolog might act as an inositol monophosphate kinase, which catalyzes a key step in InsP₆ biosynthesis. Overexpression of the homolog in transgenic rice resulted in a significant increase in total P content in seed, due to increases in InsP₆ and inorganic phosphates. On the other hand, overexpression of genes that catalyze the first and last steps of InsP₆ biosynthesis could not increase total P levels. From the experiments using developing seeds, it is suggested that the activation of InsP₆ biosynthesis in both very early and very late periods of seed development increases the influx of P from vegetative organs into seeds. This is the first report from a study attempting to elevate the P levels of seed through a transgenic approach.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.