Overexpression of RcLEC1-B, a HAP3 transcription factor of PLB from Rosa canina, increases the level of endogenous gibberellin and alters the development of cuticle and floral organs in Arabidopsis

Abstract

The HAP3 subfamily gene RcLEC1-B, was isolated from protocorm-like body (PLB) of Rosa canina, encodes 213 amino acid residues. It was shown that RcLEC1-B was specifically expressed in PLB of R. canina and its subcellular localization is in the nucleus. Overexpression of RcLEC1-B in Arabidopsis resulted in a decrease in endogenous ABA level, an increase in GA, IAA and CTK contents, and an increased number of branches. RcLEC1-B promotes the formation of spontaneous embryoids, suggesting that it may be a homolog of the Arabidopsis LEC1 gene. RcLEC1-B-OE changed the number and morphology of flower organs and resulted in open carpels and exposed ovules, along with a reduced percentage of fertile fruit. This is the first observation that overexpression of a homolog of LEC1 in Arabidopsis can lead to morphological changes in floral organs, cuticle defects, and adhesions between organs; this may result from the increased level of gibberellin in the transgenic plants.