Transcriptome analysis of wheat inflorescence development by Photoperiod-1. Photoperiod-1 regulation of wheat inflorescence development

Photoperiod insensitivity has been selected by breeders to help adapt crops to diverse environments and farming practices. In wheat, insensitive alleles of Photoperiod-1 (Ppd-1) relieve the requirement of long daylengths to flower by promoting expression of floral promoting genes early in the season; however, these alleles also limit yield by reducing the number and fertility of grain-producing florets through processes that are poorly understood. Here, we performed transcriptome analysis of the developing inflorescence using near-isogenic lines (NILs) that contain either photoperiod insensitive (Ppd-D1a) or null (ppd-1) alleles of Ppd-1, during stages when spikelet number is determined and floret development initiates. We report that Ppd-1 influences the stage-specific expression of genes with roles in auxin signalling, meristem identity, and protein turnover, and analysis of differentially expressed transcripts identified bZIP and ALOG transcription factors, named PDB1 and ALOG1, which regulate flowering time and spikelet architecture. These findings enhance our understanding of genes and that regulate inflorescence development and introduce new targets for improving yield potential.