Skip to main content
ARS Home » Midwest Area » Columbus, Ohio » Soil Drainage Research » Research » Publications at this Location » Publication #148219
Title: EXPRESSION AND NUCLEOTIDE SEQUENCE OF THE INS (3) P1 SYNTHASE (MIPS) GENE AND ITS ASSOCIATION WITH THE LOW PHYTIC ACID (LPA1-1) LOCUS ON MAIZE CHROMOSOME 1S

Author
item SHUKLA, SONI - STANFORD UNIVERSITY
item Vantoai, Tara
item PRATT, RICHARD - OHIO STATE UNIVERSITY

Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2004
Publication Date: 6/5/2004
Citation: Shukla, S., Vantoai, T.T., Pratt, R.C. 2004. Expression and nucleotide sequence of the ins (3) p1 synthase (mips) gene and its association with the low phytic acid (lpa1-1) locus on maize chromosome 1s. Journal of Agricultural and Food Chemistry. 52:4565-4570.

Interpretive Summary: A corn variety has been developed which contains two thirds less phytic acid than normal corn. Low phytic acid (lpa) corn is desirable because it provides sufficient phosphorus to satisfy animal dietary needs while reducing the environmental impact of animal manure. Additionally, it is important to know and understand how the physiological and biochemical processes differ between this lpa variety and other modern corn varieties. This study determined that the expression of a gene (MIPS gene) and the activity of an enzyme regulated by this gene were 60 % lower in the lpa corn, but there was no difference in the DNA structure. This is important information for corn geneticists and breeders.

Technical Abstract: Maize (Zea mays L.) kernels contain enough total phosphorus (P) to satisfy the dietary needs of animals. However, most of the P is in the form of phytic acid (myo-inositol-1, 2, 3, 4, 5, 6-hexakisphosphate or Ins P6), which cannot be utilized by non-ruminants. A low phytic acid maize, lpa1-1, was developed which contains total P levels similar to wild-type kernels, but the phytic acid content is reduced by 66%. The mutant phenotype could provide sufficient P to non-ruminants and help to reduce the environmental impact of animal manure. The lpa1-1 mutation has been mapped to the same region of chromosome 1S as the Ins (3) P1 synthase (MIPS) gene that encodes the first enzyme in the phytic acid biosynthetic pathway. This research was conducted to determine if the expression of the MIPS gene in lpa1-1 mutant seed is associated with the low phytic acid phenotype and to ascertain if variation in MIPS coding sequence could be inferred to be the basis of lpa1-1 mutation. We showed that MIPS activity, estimated by TLC (thin layer chromatography) autoradiography and quantitative RT-PCR, is reduced 2-3 fold in developing mutant kernels. Sequence analysis indicated that the MIPS gene has ten exons and nine introns that are highly conserved. The gene is spatially and temporally regulated but the differential gene expression appears not to be linked to a lesion in the MIPS coding region. Further research is needed to determine if a lesion exists in the promoter, the 5' UTR, or the regulatory elements controlling transcription of the gene.