**Genotypic Di** ff**erences in the E** ff**ect of P Fertilization on Phytic Acid Content in Rice Grain**

### **Ayaka Fukushima 1, Ishara Perera 2, Koki Hosoya 3, Tatsuki Akabane 3 and Naoki Hirotsu 1,3,\***


Received: 11 December 2019; Accepted: 21 January 2020; Published: 23 January 2020

**Abstract:** Phytic acid (PA) prevents the absorption of minerals in the human intestine, and it is regarded as an antinutrient. Low PA rice is beneficial because of its higher Zn bioavailability and it is suggested that the gene expression level of *myo*-inositol 3-phosphate synthase 1 (*INO1*) in developing grain is a key factor to explain the genotypic di fference in PA accumulation among natural variants of rice. P fertilization is also considered to a ffect the PA content, but it is not clear how it a ffects *INO1* gene expression and the PA content in di fferent genotypes. Here, we investigated the e ffect of P fertilization on the PA content in two contrasting rice genotypes, with low and high PA accumulation, respectively. Based on the results of the analysis of the PA content, inorganic P content, *INO1* gene expression, and xylem sap inorganic P content, we concluded that the e ffect of P fertilization on PA accumulation in grain di ffered with the genotype, and it was regulated by multiple mechanisms.

**Keywords:** inorganic P; P fertilizer; phytic acid; rice
