Analysis of the 2OG‐Fe (II) oxygenase family reveals new insights associated with flowering regulation in Saccharum spontaneum

Abstract

AbstractPlant flowering is a crucial phenomenon affecting crop yield and crossbreeding. Saccharum spontaneum is the closest wild relative sugarcane species widely used in sugarcane genetic improvement. However, the molecular interactions among the components of the flowering regulatory network of S. spontaneum are still unclear. In this study, we conducted a transcriptome sequencing approach to analyze the expressed genes on four developmental stages of panicle samples in S. spontaneum. The weighted gene co‐expression network analysis (WGCNA) results suggested that genes from the MEred (p = 3 × 10−4) module were significantly enriched in pathways of ABC transporters, photosynthesis, and circadian rhythm‐plant. Thus, 23 genes associated with flower development‐related genes were screened, including 7 AGL24, 1 FLC, 3 VIN3, 3 GA20ox, and 9 ELF3. In the gibberellic acid (GA) synthesis pathway, GA20ox, GA3ox, and GA2ox were the three enzymes that catalyzed later reactions of GA biosynthesis and belong to the 2‐oxoglutarate Fe (II) oxygenase (2OG) superfamily. Flavonoid synthesis was promoted by 2‐oxoglutarate Fe (II) oxygenase genes, a flowering hormone, which catalyzed and oxidized naringenin to dihydrokaempferol, an important precursor of florigen. Genome‐wide analysis revealed that 122 Ss2OG genes were identified in S. spontaneum, of which 99 genes were enriched in the panicle transcriptome. Furthermore, a quantitative reverse transcription polymerase chain reaction analysis showed that Ss2OG‐FeII_Oxy90, Ss2OG‐FeII_Oxy47, and Ss2OG‐FeII_Oxy89 could introduce the flower development, while Ss2OG‐FeII_Oxy34, Ss2OG‐FeII_Oxy37, and Ss2OG‐FeII_Oxy50 inhibited it. These findings provide new clues and resources for exploring the molecular mechanism of flowering regulation in S. spontaneum and promoting sugarcane breeding.