Cloning and Characterization of Maize ZmASK1, a Homologue to shaggy/GSK-3-Like Gene, Involved in Plant Responses to Abiotic Stresses

Shaggy/GSK-3-like genes play important roles in plant development and stress responses. One full-length cDNA encoding a shaggy/GSK-3 homologue, known as ZmASK1 (for abiotic stress-induced kinase), was isolated from maize (Zea mays L.) by RT-PCR. The predicted ZmASK1 protein has 426 amino acids with an estimated molecular mass of 48.5 kD and an isoelectric point of 8.7. RT-PCR analysis showed that the ZmASK1 expression was induced by mannitol, salt, and abscisic acid. Furthermore, ZmASK1 showed different expression patterns in different tissues and was the most abundant in ovaries. These results suggest that ZmASK1 may play multiple roles in abiotic stress responses as well as in plant reproductive development. This is the first isolation of shaggy/GSK-3-like gene associated with stress and development reported in maize.