Role of phytohormones in regulating agronomically important seed traits in crop plants

Abstract

Seed development is a complex process that commences after double fertilization. Both forward and reverse genetic studies have revealed the critical roles of phytohormones in regulating seed development and the associated agronomic traits. The growing evidence points to the complex interactions among underlying genetic pathways due to hormone cross talk or shared signaling components. Moving forward to deconvolute these complex interactions requires an in-depth understanding of the genes regulating individual hormone pathways. Here, we summarize the multifaceted roles of key genes regulating biosynthesis and signaling of plant hormones, and the broad spectrum of mechanisms underpinning hormone action during seed development. The gain- and loss-of-function phenotypes associated with agronomically important seed traits, namely, seed size, weight, shape, number, longevity, and dormancy, provide compelling evidence for the plant hormones as crucial metabolic engineering targets to optimize seed traits in crop plants.