Figure 10: Model of potential crosstalk between ethylene and other hormones upon ethephon spraying in sugarcane plants at the onset of ripening.
From: Ethylene-induced transcriptional and hormonal responses at the onset of sugarcane ripening
The ethephon decomposition releases ethylene and phosphoric acid, which may acidify leaf cells. This stress signal might induce NADPH oxidases and peroxidases that stimulate the production of reactive oxygen species (ROS) and, consequently, increase salicylic acid (SA) levels, leading to SA response stimulus over ethylene/jasmonic acid (JA). The ethylene in upper internodes promotes its autocatalytic biosynthesis and transcription of downstream ethylene signalling elements. JA may act synergistically with ethylene, amplifying its response in upper internodes. The synergism between ethylene and abscisic acid (ABA) is also proposed as ethylene seems to promote the expression of ABA biosynthetic genes. Ethylene and ABA may account for sucrose accumulation as ripening signals. The deactivation of gibberellin (GA) and auxin (IAA) through degradation or conjugation might also be induced by ethylene, restraining internode elongation. The genes (italic letters) shown here are placed hierarchically in their respective pathways. Upregulated genes are indicated in red and downregulated genes in blue. The relationship between components include induction (arrow heads) and repression (blocked arrows).
