Low Phytic Acid Transgenic Rice

Phytic acid, the major storage form of phosphorus in cereal grains, has a negative impact on animal nutrition and the environment. Monogastric animals cannot use the phosphorus in phytic acid efficiently because they lack the enzyme phytase needed for its digestion. Inorganic phosphate is therefore being added as supplements to animal diets to prevent phosphorus deficiency. Phytic acid is known to form complexes with metal ions such as iron, zinc, magnesium and potassium, preventing the absorption of these minerals by animals. In addition, the undigested phytic acid excreted in animal wastes is considered as the leading source of phosphorus pollution from agriculture.

By silencing the gene that encodes for the enzyme 1d-myo-inositol 3-phosphate synthase (RINO1), a team of researchers from University of Tokyo and Kobe University in Japan obtained transgenic rice lines accumulating significantly lower levels of phytic acid. The enzyme directs phytic acid synthesis in seeds.

The scientists report, on a paper published by Plant Biotechnology Journal, a 68 percent reduction in phytic acid content in GM rice seeds compared to their non-transgenic counterparts. No negative effects on seed weight, germination or plant growth were observed. In addition, the available phosphate levels of the stable transgenic plants surpassed those of currently available rice ‘low phytic acid’ mutants.

Read the paper at http://www3.interscience.wiley.com/cgi-bin/fulltext/121429897/HTMLSTART Non subscribers can read the abstract at http://www3.interscience.wiley.com/journal/121429897/abstract?CRETRY=1&SRETRY=0