Genome-Wide Identification, Characterization and Expression Profile of F-Box Protein Family Genes Shed Light on Lateral Branch Development in Cultivated Peanut (Arachis hypogaea L.)

Abstract

F-box proteins are a large gene family in plants, and play crucial roles in plant growth, development, and stress response. To date, a comprehensive investigation of F-box family genes in peanuts, and their expression pattern in lateral branch development has not been performed. In this study, a total of 95 F-box protein family members on 18 chromosomes, named AhFBX1-AhFBX95, were identified in cultivated peanut (Arachis hypogaea L.), which were classified into four groups (Group I–IV). The gene structures and protein motifs of these peanut FBX genes were highly conserved among most FBXs. We found that significant segmental duplication events occurred between wild diploid species and the allotetraploid of peanut FBXs, and observed that AhFBXs underwent strong purifying selection throughout evolution. Cis-acting elements related to development, hormones, and stresses were identified in the promoters of AhFBX genes. In silico analysis of AhFBX genes revealed expression patterns across 22 different tissues. A total of 32 genes were predominantly expressed in leaves, pistils, and the aerial gynophore tip. Additionally, 37 genes displayed tissue-specific expression specifically at the apex of both vegetative and reproductive shoots. During our analysis of transcriptome data for lateral branch development in spreading and erect varieties, namely M130 and JH5, we identified nine deferentially expressed genes (DEGs). Quantitative real-time PCR (qRT-PCR) results further confirmed the expression patterns of these DEGs. These DEGs exhibited significant differences in their expression levels at different stages between M130 and JH5, suggesting their potential involvement in the regulation of lateral branch development. This systematic research offers valuable insights into the functional dissection of AhFBX genes in regulating plant growth habit in peanut.