Gibberellins

Seed germination is tightly regulated so that it only occurs in optimal environmental conditions; for root parasitic plants, this is the presence of a potential host plant revealed by strigolactone exudates. New research shows that, unexpectedly, this response to strigolactone bypasses the core gibberellin-dependent pathway for germination.

Gibberellins (GAs) control key growth and developmental processes in plants. Real-time monitoring of GA concentrations in living tissues is critical for understanding the actions of this hormone class. A first-generation optogenetic GA-nano-indicator now illuminates the effects of GA levels on cell length and light signalling.

Semi-dwarf cereal varieties have greatly increased crop yields due to their reduced stature, but they also reduce individual spike (ear) size. However, these traits appear to be regulated by distinct pathways, opening new opportunities to develop higher yielding crops.

Brassinosteroids and gibberellins are two principal growth-promoting hormones in plants. A transcription factor called JUB1 connects their signalling and biosynthesis through positive and negative feedback loops to finely coordinate developmental output.