Abstract
Many monocots have two whorls of petaloid organs. To explain this floral morphology, modified ABC model was hypothesized that class B genes express in whorl 1 (W1), besides W2 and W3. This model was supported by the expression analysis of class B genes in tulip and agapanthus, but not in asparagus. Thus, applicability of this model in monocots remains unclear.
To inspect this model, we analyzed the tepal morphology and class B genes expression in alstroemeria, a monocot which has distinguishable outer and inner petaloid perianth. Outer and inner tepals differ in shapes but resemble in vascular bundles and epidermal cells. We isolated three class B genes (AlsDEFa, AlsDEFb and AlsGLO). AlsDEFb and AlsGLO were expressed in W1, W2 and W3, whereas AlsDEFa was detected only in W2 and W3. This supports modified ABC model and suggests that AlsDEFa expression may correlate with morphological difference of outer and inner tepals.
