Responses to environmental and chemical signals for anthocyanin biosynthesis in non-chlorophyllous corn (Zea mays L.) leaf

The effects of environmental and chemical signals on anthocyanin biosynthesis in non-chlorophyllous (white) corn leaves were investigated. Carbohydrates that caused the greatest stimulation of anthocyanin formation included fructose, glucose, and sucrose, followed by maltose, raffinose, trehalose, cellobiose, melibiose, galactose, and lactose. Sucrose enhanced the expression of anthocyanin biosynthesis genes on a transcriptional level. Carbohydrate concentration, duration of light exposure, and incubation temperature also had quantitative effects. Low temperatures stimulated anthocyanin biosynthesis whereas water stress had no effect. Abscisic acid, jasmonic acid, and ethephon also enhanced anthocyanin accumulation, although the degree of its accumulation depended on co-supplied sucrose concentrations, and was relatively lower in white tissue than in green tissue. Gibberellic acids and 6-benzylaminopurine were significantly inhibitory at the nanomolar level. Indole 3-acetic acid and salicylic acid did not influence anthocyanin synthesis in the white tissue system. Diuron inhibited its formation only in green tissue. These results indicate that the white leaf segments of corn would be good systems for research on the signal networks related to chloroplast functioning in anthocyanin biosynthesis. Additionally, this experimental system could be practical for identifying hormone-like substances, especially gibberellic acids and benzylaminopurine.