Abstract
It is well known that the phytic acid (myo-inositol-1, 2, 3, 4, 5, 6-hexakisphosphate or Ins P6) in maize (Zea mays), wheat (Triticum compactum), rice (Oryza sativa), and soybean (Glycine max) is an anti-nutritional factor in grains, phytic acid typically represents approximately 80% of maize seed total phosphorus. The identification of mutants with low phytic acid (lpa) is a possible solution to solve the problem. In this study, the content of inorganic phosphorus of twenty maize inbred lines were analyzed by col- orimetric reagent, the inorganic phosphorus content of Qi 319 was about 0.93 μg mg?1, which was higher than that of control material (0.15 μg mg?1), further investigation of phytic acid based on standard curve indicated that the content of phytic acid in Qi 319 grains was 1.31 μg mg?1, close to the maize lpa241/lpa241 mutant (1.20 μg mg?1) identified by Nielsen’s laboratory in 2003, which was significantly lower than that of Lpa241/Lpa241 wild type and control maize inbred lines (2.8 μg mg?1). F1 seeds derived from Qi 319 and wild type Lpa241/Lpa241 crossing showed low inorganic phosphorus, indicated that the gene controlling low phytic acid of Qi 319 was recessive, homozygous low phytic acid seed was identified from Qi 319 ×/Lpa241/lpa241 F1 seeds suggested that lpa loci of Qi 319 may allelic to lpa241/lpa241. To investigate the mechanism of lpa in Qi 319, the content of myo-inositol-3-phophate synthase (MIPS) was assayed Western blot by using anti-MIPS antibody derived from Arabidopsis MIPS protein, according to se quence analysis, the similarity of amino acid between maize and Arabidopsis MIPS protein is 88%. In contrast with the low content of MIPS in lpa241/lpa241, the expression of MIPS in Qi 319 increased significantly, suggesting that both mutants are related to MIPS, but their mechanism is different from each other. It is worthwhile to point out that the agronomic behavior of reported lpa mutant is not satisfying for breeding applications, while Qi 319 is a wildly used inbred line with several combinations in production. This dis- covery will broaden its application and provide a novel resource for lpa breeding program.
Published Version
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