Isolation and characterization of two APETALA1-Like genes from mango (Mangifera indica L.)

Abstract

APETALA1 (AP1) encodes a key MADS-box transcription factor that plays a crucial role in the floral transition and floral organ development. Here we describe two AP1 homologues gene MiAP1-1 and MiAP1-2 from mango (Mangifera indica L.). The full-length MiAP1-1 and MiAP1-2 were 960 bp and 906 bp, respectively, including 741 bp and 744 bp open reading frame encoding 247 and 248 amino acids, respectively. MiAP1-1 and MiAP1-2 exhibited high expression levels in floral organs and low transcript levels in vegetative organs. MiAP1-1 was more highly expressed in leaves during the floral transition stage, while MiAP1-2 was more highly expressed in leaves during the floral transition stage, floral differentiation stage and inflorescence elongation stage. Overexpression of MiAP1-1 and MiAP1-2 in Arabidopsis resulted in significant early flowering, meanwhile MiAP1-2 in transgenic tobacco also promote early flowering. Ectopic expression of MiAP1-1 and MiAP1-2 causes different flower phenotypes. MiAP1-1 caused the side branch flower organs mutate, while MiAP1-2 produced terminal flowers in the main stem shoots and also in the side branch. Several floral integrator genes were upregulated in the overexpression transgenic plant lines. These observations indicated that the two MiAP1 homologue genes in mango functions in the floral transition and floral organ development.