E2 family and evening complex identify soybean photoperiod sensitivity

Soybean is a facultative short-day plant, and its high photoperiod sensitivity poses challenges for breeding widely adapted soybean cultivars. Although the genetic basis of photoperiod in plants has been extensively studied, mutations in most of the photoperiod genes usually weaken sensitivity rather than eliminate it. Recently, Zhao et al. (2024) discovered that the E2 family plays a crucial role in determining soybean photoperiod sensitivity. The triple mutant e2 e2la e2lb exhibits similar flowering time under both long-day and short-day conditions. Further investigation uncovered a translational-transcriptional suppression loop between E2 and evening complex that constitutes another key factor in determining soybean photoperiod sensitivity.