Expression and Nucleotide Sequence of an INS (3) P1 Synthase Gene Associated with Low-Phytate Kernels in Maize (Zea mays L.)
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- 作者：Soni Shukla ; Tara T. VanToai ; and Richard C. Pratt
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2004
- 出版时间：July 14, 2004
- 年：2004
- 卷：52
- 期：14
- 页码：4565 - 4570
- 全文大小：121K
- 年卷期：v.52,no.14(July 14, 2004)
- ISSN：1520-5118
文摘
Most of the phosphorus (P) in maize (Zea mays L.) kernels is in the form of phytic acid. A low phyticacid (lpa) maize mutant, lpa1-1, displays levels reduced by 66%. A goal of genetic breeding isdevelopment of low phytic acid feedstocks to improve P nutrition of nonruminant animals and reducethe adverse environmental impacts of excess P in manure. The genetic basis of the lpa1-1 mutationis not known, but previous genetic mapping has shown both the mutant phenotype and the Ins (3) P1synthase (MIPS) gene, which encodes the first enzyme, myo-inositol phosphate synthase, in thephytic acid biosynthetic pathway, map to the same chromosomal region in maize. Research wasconducted to determine the expression of the MIPS gene in lpa1-1 and wild-type kernels with similargenetic backgrounds and to ascertain if variation in the MIPS coding sequence could be inferred tobe the basis of the mutation. MIPS enzyme activity determined by TLC was reduced 2-3-fold inmutant kernels. RT-PCR-based experiments using primers specific for the 1S-MIPS sequenceindicated gene expression was reduced 50-60% in the mutant. Sequence analysis of the MIPSgenomic sequence revealed 10 exons and 9 introns that are identical in both mutant and wild-typedeveloping kernels. These findings support an association between reduced MIPS gene activity andlow phytic acid content, but additional research should examine the promoter, the 5'UTR, ortranscriptional controlling elements of the MIPS gene to ascertain the possible presence of a geneticlesion in those regions.Keywords: Zea mays L.; gene activity and sequence analysis; low phytic acid; Ins (3) P1 synthase