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ZmPTR1, a maize peptide transporter expressed in the epithelial cells of the scutellum during germination

Tnani, Hedia, López-Ribera, Ignacio, García-Muniz, Nora, Vicient, Carlos M.
Plant science 2013 v.207 pp. 140-147
Arabidopsis thaliana, auxins, corn, endosperm, enzymatic hydrolysis, epithelial cells, epithelium, genes, germination, peptide transporters, peptides, storage proteins
In plants, peptide transporter/nitrate transporter 1 (PTR/NRT1) family proteins transport a variety of substrates such as nitrate, di- and tripepetides, auxin and carboxylates across membranes. We isolated and characterized ZmPTR1, a maize member of this family. ZmPTR1 protein sequence is highly homologous to the previously characterized di- and tripeptide Arabidopsis transporters AtPTR2, AtPTR4 and AtPTR6. ZmPTR1 gene is expressed in the cells of the scutellar epithelium during germination and, to a less extent, in the radicle and the hypocotyl. Arabidopsis thaliana lines overexpressing ZmPTR1 performed better than control plants when grown on a medium with Ala-Ala dipeptide as the unique N source. Our results suggest that ZmPTR1 plays a role in the transport into the embryo of the small peptides produced during enzymatic hydrolysis of the storage proteins in the endosperm.