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ARS Home » Midwest Area » Columbus, Ohio » Soil Drainage Research » Research » Publications at this Location » Publication #127726
Title: MOLECULAR GENETICS OF THE CORN LOW PHYTIC ACID (LPA) TRAIT

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

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/2001
Publication Date: 11/1/2001
Citation: Shukla, S., Vantoai, T.T., Pratt, R. 2001. Molecular genetics of the corn low phytic acid (lpa) trait. Agronomy Abstracts.

Interpretive Summary:

Technical Abstract: Corn contains enough total phosphorus (P) to satisfy the dietary needs of non-ruminant animals. However, about 75% of the total P in corn grains is in the unusable organic form known as phytic acid. A low phytic acid corn mutant was developed. The 1pal mutation was mapped to the same position on the 1S chromosome with the MIPS gene coding for myo-inositol phosphate synthase, the first enzyme in the phytic acid biosynthetic pathway. We hypothesized that the lpal1 mutation was caused by a lesion in the MIPS gene. We found that MIPS expression, estimated by TLC autoradiography and quantitative RT-PCR, is reduced 4- to 5- fold in developing lpa1 mutant kernels. Sequence analysis showed no difference in the 3618-nucleotide MIPS sequences between two pairs of near isogenic wild-type and lpa1 maize inbred lines. Two F2 populations from crosses of wild-type and lpa1 parents were grown in the field. In order to identify a useful molecular marker, 20 SSR markers that mapped in the vicinity of the MIPS locus on the 1S chromosome were screened. One marker that was polymorphic between the parents was identified. We are currently using this DNA marker to identify appropriate progeny lines for incorporating the low phytic phenotype into elite inbreds. Marker-assisted backcross breeding will reduce the time required in back-crossing by 50% and facilitate development of enhanced-trait hybrids.