DELAY OF GERMINATION 1, the Master Regulator of Seed Dormancy, Integrates the Regulatory Network of Phytohormones at the Transcriptional Level to Control Seed Dormancy

Abstract

Seed dormancy, an important adaptive trait that governs germination timing, is endogenously controlled by phytohormones and genetic factors. DELAY OF GERMINATION 1 (DOG1) is the vital genetic regulator of dormancy, significantly affecting the expression of numerous ABA and GA metabolic genes. However, whether DOG1 could influence the expression of other phytohormone-related genes is still unknown. Here, we comprehensively investigated all well-documented hormone-related genes which might be affected in dog1–2 dry or imbibed seeds by using whole-transcriptome sequencing (RNA-seq). We found that DOG1 could systematically control the expression of phytohormone-related genes. An evident decrease was observed in the endogenous signal intensity of abscisic acid (ABA) and indole-3-acetic acid (IAA), while a dramatic increase appeared in that of gibberellins (GA), brassinosteroids (BR), and cytokinin (CK) in the dog1–2 background, which may contribute considerably to its dormancy-deficient phenotype. Collectively, our data highlight the role of DOG1 in balancing the expression of phytohormone-related genes and provide inspirational evidence that DOG1 may integrate the phytohormones network to control seed dormancy.