Identification of a new mutant allele of that regulates kernel development and nutritional quality in maize.

Unlabelled: The discovery and characterization of the opaque endosperm gene provide ideas and resources for the production and application of maize. We found an mutant whose phenotype was opaque and shrunken endosperm with semi-dwarf plant height. The protein, lipid, and starch contents in the endosperm were significantly decreased, while the free amino acid content in the endosperm significantly increased. The aspartic acid, asparagine, and lysine contents were raised in the endosperm by 6.5-, 8.5-, and 1.7-fold, respectively. Genetic analysis showed that this mutant is a recessive single-gene mutation. The position mapping indicated that is located in a 468-kb region that contains 11 protein-encoding genes on the long arm of chromosome 5. The coding sequence analysis of candidate genes between the WT and showed that had only a single-base substitution (A-G) in the fifth exon, which caused methionine substitution to valine. Sequence analysis and the allelic test showed that is a new mutant allele of . The qRT-PCR results indicated that is highly expressed in the stalks and anthers. Subcellular localization studies showed that is a membrane transporter. In the variation analysis of , the amplification of 65 inbred lines in GWAS showed that this 3-bp deletion of the first exon of was found only in temperate inbred lines, implying that the gene was artificially affected in the selection process. Our results suggest that is an important endosperm development gene and may serve as a genetic resource.

Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-022-01278-9.