Amino acid permease 6 regulates grain protein content in maize

Grain protein content (GPC) is an indicator of cereal nutritional quality. Identification of genes involved in the regulation of GPC provides targets for molecular breeding for crop protein quality. We characterized a maize gene encoding the putative amino acid transporter ZmAAP6, a gene expressed mainly in immature seeds, especially in the basal endosperm transfer layer. Total protein and zein contents were decreased in ZmAAP6 null mutants and increased in ZmAAP6 overexpression (OE) lines, consistent with their changed in the size of protein bodies. Metabolic and transcriptomic analysis supported the regulatory role of ZmAAP6 in amino acid transportation. These results suggest that ZmAAP6 functions as a positive regulator of GPC in maize, shedding new light on the genetic basis of GPC regulation. (C) 2022 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

Automated summary

This study identified the positive regulatory role of ZmAAP6, a maize gene, in grain protein content (GPC) regulation. Mutant and overexpression analysis revealed its involvement in protein body formation and amino acid transportation.