Characterization and Transcriptome Analysis of Maize Small-Kernel Mutant <i>smk7a</i> in Different Development Stages
Jing Wang,
Hongwu Wang,
Kun Li,
Xiaogang Liu,
Xiaoxiong Cao,
Yuqiang Zhou,
Changling Huang,
Yunling Peng,
Xiaojiao Hu
Affiliations
Jing Wang
College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China
Hongwu Wang
College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China
Kun Li
National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Xiaogang Liu
National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Xiaoxiong Cao
National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Yuqiang Zhou
National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Changling Huang
National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Yunling Peng
College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China
Xiaojiao Hu
National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
The kernel serves as a storage organ for various nutrients and determines the yield and quality of maize. Understanding the mechanisms regulating kernel development is important for maize production. In this study, a small-kernel mutant smk7a of maize was characterized. Cytological observation suggested that the development of the endosperm and embryo was arrested in smk7a in the early development stage. Biochemical tests revealed that the starch, zein protein, and indole-3-acetic acid (IAA) contents were significantly lower in smk7a compared with wild-type (WT). Consistent with the defective development phenotype, transcriptome analysis of the kernels 12 and 20 days after pollination (DAP) revealed that the starch, zein, and auxin biosynthesis-related genes were dramatically downregulated in smk7a. Genetic mapping indicated that the mutant was controlled by a recessive gene located on chromosome 2. Our results suggest that disrupted nutrition accumulation and auxin synthesis cause the defective endosperm and embryo development of smk7a.
