Integration of multiple signaling pathways shapes the auxin response.

The phytohormone auxin is a pivotal signaling molecule that functions throughout the plant lifecycle. Proper regulation of the auxin response is critical for optimizing plant growth under ever-changing environmental conditions. Recent studies have demonstrated that the signaling components that modulate auxin sensitivity and responses are functionally and mechanically diverse. In addition to auxin itself, various environmental and hormonal signals are integrated to modulate the auxin response through directly controlling auxin signaling components. This review explores the non-canonical mechanisms that modulate auxin signaling components, including transcriptional, translational, and post-translational regulation. All of these contribute to the wide range in sensitivity and complexity in auxin responses to various signaling cues.