Dynamic gene regulatory networks improving spike fertility through regulation of floret primordia fate in wheat

Abstract

The developmental process of spike is critical for spike fertility through affecting floret primordia fate in wheat; however, the genetic regulation of this dynamic and complex developmental process remains unclear. Here, we conducted a high temporal‐resolution analysis of spike transcriptomes and monitored the number and morphology of floret primordia within spike. The development of all floret primordia in a spike was clearly separated into three distinct phases: differentiation, pre‐dimorphism and dimorphism. Notably, we identified that floret primordia with meiosis ability at the pre‐dimorphism phase usually develop into fertile floret primordia in the next dimorphism phase. Compared to control, increasing plant space treatment achieved the maximum increasement range (i.e., 50%) in number of fertile florets by accelerating spike development. The process of spike fertility improvement was directed by a continuous and dynamic regulatory network involved in transcription factor and genes interaction. This was based on the coordination of genes related to heat shock protein and jasmonic acid biosynthesis during differentiation phase, and genes related to lignin, anthocyanin and chlorophyll biosynthesis during dimorphism phase. The multi‐dimensional association with high temporal‐resolution approach reported here allows rapid identification of genetic resource for future breeding studies to realise the maximum spike fertility potential in more cereal crops.

Phenotypic and transcriptome profiling of spikes reveals the regulation of light regimens on spike growth and fertile floret number in wheat

“…The morphological development of FP before polarization was a significant factor in restricting the increase of NFFs. Ugarte et al (2010) showed that a low red/far-red ratio accelerated floret development and was associated with a lower number of living florets; on the contrary, Zhang et al (2023) found that accelerating morphological development of FP by increasing plant space improved the number of fertile florets in wheat. One possible reason for the discrepancies between these studies was that a 'stress treatment' or 'optimization treatment' was applied to the plants, which affected the plant's adjustment and use of available resources.…”