Fine mapping and candidate gene analysis of maize defective kernel mutant <italic>dek54</italic>

Maize kernel is closely related to yield and nutritive quality. Study on the function of maize development relative genes provides important basis for molecular mechanism analysis, increasing quality improving. B73 pollen was treated with ethyl methylmethanesulfonate (EMS) a defective defective 54 (dek54) screened. dek54 had small mature kernel, wrinkled whitened seed coat phenotype. Genetic analysis indicated that recessive mutant controlled by single gene. Paraffin sections showed starchy endosperm cells irregular shape dense arrangement at developmental stage. Scanning electron microscopy observation protein bodies around starch granules in central region dek54 mature were fewer arranged more loosely compare wild type. Total protein, zein, amino acids components contents total nitrogen content significantly lowered compared located chromosome 7 within interval physical distance about 290 kb between markers SSR6 SSR7. Sequencing revealed 351th base G 2nd exon Zm00001d019294 gene changed into A, which led premature termination translation. Zm00001d019294 gene specifically expressed immature has highest expression 12 DAP (days after pollination) kernel. Targeted mutation performed using CRISPR/Cas9 system identify phenotype caused candidate Zm00001d019294. Dek54 encoded an MFS (major facilitator superfamily) high homology ZmNRT1.5 (nitrate transporter). Besides, Dek54 localized plasma membrane protoplasts. The study laid foundation development.