The sugar transporter ZmSUGCAR1 of the nitrate transporter 1/peptide transporter family is critical for maize grain filling

• DOI: 10.1093/plcell/koac256
• Publication Date: 2022-09-01T14:50:12Z
• Authors: Bo Yang; Jing Wang; Miao Yu; Meiling Zhang; Yanting Zhong; Tianyi Wang; Peng Liu; Weibin Song; Haiming Zhao; Astrid Fastner; Marianne Suter; Doris Rentsch; Uwe Ludewig; Weiwei Jin; Dietmar Geiger; Rainer Hedrich; David M Braun; Karen E Koch; Donald R McCarty; Wei-Hua Wu; Xuexian Li; Yi Wang; Jinsheng Lai
• Keywords: 0301 basic medicine; 2. Zero hunger; Sucrose; 0303 health sciences; Nitrate Transporters; Biological Transport; Zea mays; Peptide Transporter 1; 03 medical and health sciences; Glucose; HEK293 Cells; Humans; Edible Grain; Plant Proteins

Maternal-to-filial nutrition transfer is central to grain development and yield. nitrate transporter 1/peptide (NRT1-PTR)-type transporters typically transport nitrate, peptides, ions. Here, we report the identification of a maize (Zea mays) NRT1-PTR-type that transports sucrose glucose. The activity this sugar transporter, named Sucrose Glucose Carrier 1 (SUGCAR1), was systematically verified by tracer-labeled uptake serial electrophysiological studies including two-electrode voltage-clamp, non-invasive microelectrode ion flux estimation assays in Xenopus laevis oocytes patch clamping HEK293T cells. ZmSUGCAR1 specifically expressed basal endosperm layer loss-of-function mutation caused significantly decreased glucose contents subsequent shrinkage kernels. Notably, orthologs SbSUGCAR1 (from Sorghum bicolor) TaSUGCAR1 Triticum aestivum) displayed similar activities oocytes, supporting functional conservation SUGCAR1 closely related cereal species. Thus, discovery uncovers type essential for opens potential avenues genetic improvement seed-filling yield other crops.