Production of two Highly Active Bacterial Phytases with Broad pH Optima in Germinated Transgenic Rice Seeds

Chwan-Yang Hong; Kuo-Joan Cheng; Tung-Hai Tseng; Chang-Sheng Wang; Li-Fei Liu; Su-May Yu

doi:10.1023/B:TRAG.0000017158.96765.67

Production of two Highly Active Bacterial Phytases with Broad pH Optima in Germinated Transgenic Rice Seeds

Resource

Transgenic Research 13(1): 29-39

Journal

Transgenic Research

Journal Volume

13

Journal Issue

1

Pages

29-39

Date Issued

2004-02

Date

2004-02

Author(s)

Chwan-Yang Hong

Kuo-Joan Cheng

Tung-Hai Tseng

Chang-Sheng Wang

Li-Fei Liu

Su-May Yu

DOI

10.1023/B:TRAG.0000017158.96765.67

URI

https://scholars.tari.gov.tw/handle/123456789/1792

Abstract

Phytate is the main storage form of phosphorus in many plant seeds, but phosphate bound in this form is not available to monogastric animals. Phytase, an enzyme that hydrolyzes phosphate from phytate, has the potential to enhance phosphorus availability in animal diets when engineered in rice seeds as a feed additive. Two genes, derived from a ruminal bacterium Selenomonas ruminantium (SrPf6) and Escherichia coli (appA), encoding highly active phytases were expressed in germinated transgenic rice seeds. Phytase expression was controlled by a germination inducible -amylase gene (Amy8) promoter, and extracellular phytase secretion directed by an Amy8 signal peptide sequence. The two phytases were expressed in germinated transgenic rice seeds transiently and in a temporally controlled and tissue-specific manner. No adverse effect on plant development or seed formation was observed. Up to 0.6 and 1.4 U of phytase activity per mg of total extracted cellular proteins were obtained in germinated transgenic rice seeds expressing appA and SrPf6 phytases, respectively, which represent 46–60 times of phytase activities compared to the non-transformant. The appA and SrPf6 phytases produced in germinated transgenic rice seeds had high activity over broad pH ranges of 3.0–5.5 and 2.0–6.0, respectively. Phytase levels and inheritance of transgenes in one highly expressing plant were stable over four generations. Germinated transgenic rice seeds, which produce a highly active recombinant phytase and are rich in hydrolytic enzymes, nutrients and minerals, could potentially be an ideal feed additive for improving the phytate-phosphorus digestibility in monogastric animals.

Subjects

feed additive

germinating seeds

phytase

rice

Publisher

Chapman & Hall

Type

journal article

File(s)

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