**Phytic Acid and Transporters: What Can We Learn from** *low phytic acid* **Mutants?**

### **Eleonora Cominelli 1,\*, Roberto Pilu 2 and Francesca Sparvoli 1**


Received: 22 November 2019; Accepted: 1 January 2020; Published: 5 January 2020

**Abstract:** Phytic acid has two main roles in plant tissues: Storage of phosphorus and regulation of di fferent cellular processes. From a nutritional point of view, it is considered an antinutritional compound because, being a cation chelator, its presence reduces mineral bioavailability from the diet. In recent decades, the development of low phytic acid (*lpa*) mutants has been an important goal for nutritional seed quality improvement, mainly in cereals and legumes. Di fferent *lpa* mutations affect phytic acid biosynthetic genes. However, other *lpa* mutations isolated so far, a ffect genes coding for three classes of transporters: A specific group of ABCC type vacuolar transporters, putative sulfate transporters, and phosphate transporters. In the present review, we summarize advances in the characterization of these transporters in cereals and legumes. Particularly, we describe genes, proteins, and mutants for these di fferent transporters, and we report data of in silico analysis aimed at identifying the putative orthologs in some other cereal and legume species. Finally, we comment on the advantage of using such types of mutants for crop biofortification and on their possible utility to unravel links between phosphorus and sulfur metabolism (phosphate and sulfate homeostasis crosstalk).

**Keywords:** phytic acid; low phytic acid mutants; MRP transporter; ABCC transporter; SULTR transporter; Pht; phosphate transporter; sulfate transporter
