ZmMYB155 is involved in starch synthesis and basal endosperm transfer layer development in maize.

Key message: ZmMYB155 acts as an important regulatory factor in starch synthesis and BETL development in maize. Starch synthesis is a critical process determining both the grain quality and quantity of a crop. The basal endosperm transfer layer (BETL) plays a crucial role in nutrient transport and defense against pathogens. However, the regulation of this process in maize remains elusive. This study demonstrated that ZmMYB155 is involved in starch synthesis and BETL development in maize kernels. ZmMYB155 is highly expressed in the maize endosperm. ZmMYB155 is a typical R2R3-MYB transcription factor that localized in the nucleus and cytoplasm. Compared to those of the control, the myb155 mutant displayed reduced seed size, starch, amylose, and amylopectin contents, and increased soluble sugars. Abnormal starch chain length distribution was also observed in the myb155 mutant. Furthermore, BETL development defects were observed in the myb155 mutant. In line with this, a significant decrease in the expression levels of starch synthesis pathway and BETL-specific genes was detected in the myb155 mutant. Collectively, these results demonstrate that ZmMYB155 acts as an important regulatory factor in starch synthesis and BETL development in maize.