An APETALA1-like gene of soybean regulates flowering time and specifies floral organs

MADS-box proteins are key transcription factors involved in plant reproductive development. APETALA1 (AP1) in Arabidopsis is a MIKC-type MADS-box gene and plays important roles in flower development. In this research, we isolated and characterized GmAP1, which encoded an AP1-like protein in soybean. GmAP1 contained eight exons and seven introns and was specifically expressed in the flower, especially in the sepal and petal. GmAP1 was a nucleus-localized transcription factor and displayed transactivation activity. It caused early flowering and alteration of floral organs when ectopically expressed in tobacco. To our knowledge, this is the first report characterizing an AP1-like gene from soybean.