Genome-wide identification and expression analysis of GA20ox and GA3ox genes during pod development in peanut.

Background: Gibberellins (GAs) play important roles in regulating peanut growth and development. and are key enzymes involved in GA biosynthesis. These enzymes encoded by a multigene family belong to the 2OG-Fe (II) oxygenase superfamily. To date, no genome-wide comparative analysis of peanut and -encoding genes has been performed, and the roles of these genes in peanut pod development are not clear.

Methods: A whole-genome analysis of and gene families in peanut was carried out using bioinformatic tools. The expression of these genes at different stage of pod development was analyzed using qRT-PCR.

Results: In this study, a total of 15 and five genes were identified in peanut genome, which were distributed on 14 chromosomes. Phylogenetic analysis divided the GA20oxs and GA3oxs into three groups, but and in two groups. The conserved pattern of gene structure, cis-elements, and protein motifs further confirmed their evolutionary relationship in peanut. and genes were differential expressed at different stages of pod development. The strong expression of , , and in S1-stage indicated that these genes could have a key role in controlling peg elongation. Furthermore, and also showed diverse expression patterns in different peanut tissues including leaves, main stems, flowers and inflorescences. Noticeably, and were highly expressed in the main stem, whereas the and were strongly expressed in the inflorescence. The expression levels of , , , and were high in the flowers, suggesting their involvement in flower development. These results provide a basis for deciphering the roles of and in peanut growth and development, especially in pod development.