A wheat phytohormone atlas spanning major tissues across the entire life cycle provides novel insights into cytokinin and jasmonic acid interplay.

Abstract

Although numerous studies have focused on the specific organs or tissues at different development stages or under various abiotic and biotic stress, our understanding of the distribution and relative abundance of phytohormones throughout the entire life cycle of plant organs and tissues remains insufficient. Here, we present a phytohormone atlas resource covering the quantitative analysis of eight major classes of phytohormones, comprising a total of 40 hormone-related compounds, throughout the complete life cycle of wheat. In combination with transcriptome analysis, we established a Wheat Phytohormone Metabolic Regulatory Network (WPMRN). Using our WPMRN dataset and GO enrichment analysis, we swiftly characterized the function of TaLOG5-B1 in cytokinin biosynthesis. Furthermore, a detailed investigation of the WPMRN dataset uncovered transcription factor-mediated co-regulation mechanisms among different classes of phytohormones. We focused specifically on the metabolic regulatory involving cytokinin and jasmonic acid. To achieve this, we characterized genes TaLOG3-D1 and TaAOS-D1 involved in the biosynthesis of these phytohormones, along with their regulatory transcription factors TaDOF3A and TaDOF5.6B. The functions of these genes were validated in transgenic plants, revealing their ability to co-regulate radicle length. These findings serve as a case study that highlights the utility of this resource for studying phytohormone metabolic regulatory networks in cereal crops and for gaining insights into the roles of phytohormones in enhancing agronomic traits.