Genome-wide identification of the mango auxin response factor family and the ectopic expression of two ARF (MiARF18A) genes confers early flowering and increases silique number in transgenic Arabidopsis

• Ectopic overexpression of two MiARF18As promotes early flowering and increases silique number in Arabidopsis. • Overexpression of two MiARF18As significantly increases the content of endogenous indole acetic acid in transgenic Arabidopsis. • MiARF18A1 and MiARF18A2 may interact with MiFUL and MiAP1–2 proteins. The ARF subfamily belongs to the B3 superfamily, the members of which are extensively expressed in plants and play important roles in root, flower and fruit development and the response to stress. In the present study, ARF gene family members in mango were identified and analyzed. Twenty-nine MiARF genes were found to be randomly distributed across 15 chromosomes, and could be classified into three subfamilies based on their phylogenetic relationships and encoded protein domain structures. An analysis of the promoters of these genes revealed several hormone and stress response elements, but different genes presented different response elements. Expression analysis revealed that the relative expression levels of most MiARF s were highest at the fruit-setting stage and decreased during fruit development. To further investigate the function of MiARFs , two ARF genes, MiARF18A1 and MiARF18A2 , were selected for functional studies. The results revealed that MiARF18A1 and MiARF18A2 were localized in the nucleus. The overexpression of MiARF18A1 and MiARF18A2 not only promoted early flowering but also significantly increased the number of siliques and the content of endogenous indole acetic acid in transgenic Arabidopsis. Yeast two-hybrid analysis revealed that MiARF18A1 and MiARF18A2 interact with the MiFUL and MiAP1–2 proteins. This study aimed to explore the characteristics of mango ARF family members through bioinformatics and functional validation, particularly the specific roles of MiARF18A1 and MiARF18A2 in flower and fruit development. These results suggest that MiARF18As may play positive roles in mango flowering and fruit development and may provide new insights into the hormone regulatory network of mango.