Phytic acid (myo-inositol 1,2,3,4,5,6-hexakisphosphate; InsP₆) is the main storage form of phosphorus in plant seeds, and it decreases the bioavailability of minerals in the feed of monogastric animals. The enzyme myo-inositol-1-phosphate synthase (MIPS, EC 5.1.1.4) catalyzes the conversion of D-glucose-6-phosphate to myo-inositol-1-phosphate, which is the initial step of phytic acid biosynthesis. To date, there is no information about the relationship between the expression of MIPS and the accumulation of phytic acid in developing oat seeds. In the present study, MIPS was isolated by rapid amplification of cDNA ends (RACE)-PCR method from the early developing oat seeds by using three consensus primers which were designed from highly conserved regions in the MIPS sequence from other plants. We examined the changes in the expression of MIPS and accumulation of phytic acid in different seed development stages, as well as the changes in total P (TP), Ca, and Mg concentrations during seed maturation. The results of RACE-PCR and northern blot showed that the maximal MIPS transcription level was observed at 5 days after flowering (DAF), and it was not detected in stems and leaves. Phytic acid was first detected at 25 DAF, when the inorganic P (Pi) level was 8.4-fold lower and the phytic acid P (Phy-P) level was 7.3-fold higher than those after 30 DAF. The TP, Ca, and Mg concentrations increased with the progress of seed maturation. These results indicate that MIPS was only expressed in seeds at the early stage of seed development, after which the seeds started to accumulate phytic acid. In addition, TP, Ca, and Mg are accumulated during seeds maturation.

植酸（myo - inositol 1,2,3,4,5,6-hexa kis phosphate；InsP ₆）是植物种子中磷的主要储存形式，它降低了单胃动物饲料中矿物质的生物利用度。酶肌醇肌醇-1-磷酸合酶（MIPS，EC 5.1.1.4）催化d葡萄糖-6-磷酸到的转化肌醇肌醇-1-磷酸，这是植酸生物合成的初始步骤。迄今为止，尚无关于MIPS表达与燕麦种子发育过程中植酸积累之间关系的信息。在本研究中，MIPS使用从其他植物的MIPS序列中高度保守的区域设计的三个共有引物，通过 cDNA 末端的快速扩增 (RACE)-PCR 方法从早期发育的燕麦种子中分离。我们检查了不同种子发育阶段MIPS表达和植酸积累的变化，以及种子成熟过程中总 P (TP)、Ca 和 Mg 浓度的变化。RACE-PCR和northern blot结果表明，最大MIPS在开花后 5 天（DAF）观察到转录水平，在茎和叶中未检测到。在 25 DAF 时首次检测到植酸，此时无机 P (Pi) 水平比 30 DAF 后低 8.4 倍，植酸 P (Phy-P) 水平高 7.3 倍。TP、Ca 和 Mg 的浓度随着种子成熟的进行而增加。这些结果表明MIPS仅在种子发育的早期在种子中表达，此后种子开始积累植酸。此外，TP、Ca 和 Mg 在种子成熟过程中积累。