Low-Temperature and Light Pretreatment Interactively Promote Rapid Flowering, Early Ripening, and Yield Accumulation...

Exposing wheat (Triticum aestivum L.) seeds to a combination of light and low temperatures for 4-6 weeks, followed by transferring to speed breeding (SB) conditions, has been demonstrated to effectively reduce generation time in winter wheat. To reveal the underlying mechanisms of accelerated generation advancement in winter wheat, we investigated changes in transcriptome and the subsequent responses in plant growth, flowering of germinated seeds vernalized at 4 °C with white exposure (VL) or under dark conditions (VD) for 4 weeks before sowing, and subsequent growth under SB conditions. Germinated seeds without vernalization were directly sown under SB conditions and served as controls (Control). The results showed that, compared with Control and VD, VL significantly expedited vernalization, resulting in early flowering for around 6 days and accelerated ripening of progeny seeds for 13 days with a higher germination index and vigor index. The transcriptomic analysis revealed that the differently expressed genes (DEGs) involved in GA synthesis and its signal transduction both participated in the light-induced speed vernalization and the subsequent rapid growth and development of winter wheat. The MADS-box transcription factors, especially VRN-A1 and MADS55, might play a vital role in the light- and low-temperature-induced early flowering. Our results stress the importance of light in vernalization and lay the groundwork for further elucidating the mechanisms underlying the light-induced speed vernalization of winter wheat.