Transcriptome profiling at heading time uncovered stage and spatial tissue-specific QTL in winter wheat

The transition from vegetative to floral phase is the result of a complex crosstalk of exogenous and endogenous floral integrators. This network controlling flowering time is not deciphered largely in wheat. In this study, we selected two bred winter cultivars developed in Germany showing contrasting and stable flowering behavior in different environments for a global transcriptomic investigation at heading time. The microscopical phenotyping of the main shoot apex (MSA) revealed the acceleration of MSA development of the early flowering cultivar C207 compared to the late flowering one C152 in the three phases of inflorescence development and asserts the phenotypes observed in the field. By integrating quantitative trait loci (QTL) mapping and transcriptome profiling of inflorescence phases, 664 and 1076 differentially expressed genes (DEGs) in early C207 compared to late C152 in MSA and leaf tissue, respectively, could be mapped in 27 QTL intervals associated with heading date.