including cytokinins and gibberellic acids. Interestingly, inhibition of
ethylene in the system is sufficient to yield inflated calyx in Withania. In contrast, Tubocapsicum, a closely
related species and an evolutionary natural loss mutant of ICS – showed no response to applied hormones,
and ethylene led to inflation of the receptacle indirectly. In addition to hormones, the expression of
an MPF2-like MADS-box transcription factor in sepals is essential for ICS formation. Nevertheless, the
interactions between MPF2-like genes and hormones are barely detectable at the transcript level. Our data
provide insight into the role of hormones in generating floral morphological diversity during evolution.