Changes in plant hormones and transcriptome behind the three pistils formation in wheat

Auxin and gibberellin significantly influence plant pistil development, but their specific roles in the formation of the three pistils trait in wheat are still unclear. To investigate the effects of auxin and gibberellin on the three pistils trait in wheat, we measured the contents of auxin and gibberellin in young spikes from three pistils wheat (TP and CM28TP) and single pistil wheat (CM28) at three stages. We also performed transcriptome sequencing. A total of 14 different auxins and 7 different gibberellins were detected from all samples, among which the contents of IAA-Glc and GA19 showed significant differences among different samples. The transcriptome sequencing yielded over 1.28 billion clean reads and 3.2 million transcripts. A total of 2,018 and 6,163 differentially expressed genes (DEGs) were identified from the comparisons of CM28 vs CM28TP and CM28 vs TP, respectively. Through the correlation analysis between auxin, gibberellin, and DEGs, 4 ARF genes, 3 AMI genes, and 3 DELLA genes were identified. These results suggest that IAA-Glc, GA19, and the 10 key genes were crucial factors in the formation of three pistils trait. Further analysis showed that ARF expression level and GA contents were negatively correlated with three pistils trait, while DELLA expression level and auxin contents were positively correlated. This study suggests that auxin and gibberellin signal transduction have an antagonistic relationship during wheat flower development, influencing the formation of the three pistils. This discovery helps further understanding of the mechanism behind the formation of the three pistils trait and provides theoretical support for the cultivation of high-yield wheat.