Zea mays multidrug resistance-associated protein 4 (ZmMRP4) (ZmMRP4)

ZmMRP4 (Zea mays multidrug resistance-associated protein 4) is an ATP-binding cassette (ABC) transporter belonging to the ABCC subfamily, primarily localized to the tonoplast of maize seed cells (Shi et al., 2007). It functions as a high-affinity transporter for phytic acid (myo-inositol hexakisphosphate), facilitating its sequestration into vacuoles during seed development (Shukla et al., 2004). Mutations in the ZmMRP4 gene lead to the 'low phytic acid 1' (lpa1) phenotype, which is characterized by a significant reduction in phytic acid and a concomitant increase in inorganic phosphorus within the grain (Raboy, 2001). This protein is a major target in agricultural biotechnology for the development of biofortified crops, as phytic acid is an anti-nutrient that binds essential minerals like zinc and iron, preventing their absorption in humans and monogastric animals (Raboy, 2009). Furthermore, reducing phytic acid in animal feed helps mitigate environmental phosphorus pollution caused by animal waste (Shi et al., 2007). However, the disruption of ZmMRP4 often results in pleiotropic effects, including reduced seed germination and impaired plant stress responses, which remain significant challenges for commercial implementation (Pilu et al., 2003).

Other names

lpa1low phytic acid 1ZmABCC4GRMZM2G067515PCO091534

No known pharmacological drugs; targeted via genetic modification or gene silencing to inhibit the active transport of phytic acid (IP6) from the cytoplasm into the storage vacuoles of developing seeds (Shi et al., 2007).