In flowering plants, lateral organs including stamens develop according to the precise regulation of adaxial-abaxial polarity. However, the polarity establishment process is poorly understood in asymmetric stamens. Canna indica (Zingiberales: Cannaceae) is a common ornamental plant with an asymmetric stamen comprising a one-theca anther and a petaloid appendage. In this study, we depicted the monosymmetric-to-asymmetric morphogenesis of C. indica stamen, and the morphogenesis of the monosymmetric stamen of a sister species was used as a contrast. We chose a HD-ZIP III gene family member and a YABBY family member as the adaxial and abaxial polarity marker genes respectively and tested their expression using mRNA in situ hybridization. The expression patterns of the two genes changed dynamically and asymmetrically during the stamen development process. Compared with their homologs in Arabidopsis thaliana, these two genes exhibited some specific expression patterns. We hypothesize that the distinctive adaxial-abaxial polarity participates in the irregular morphogenesis of C. indica stamen, which mediates the putative stamen-to-petaloid staminode conversion in this species.
Canna indica is a common ornamental plant with asymmetric flowers having colourful petaloid staminodes. The only fertile stamen comprises a one‐theca anther and a petaloid appendage and represents the lowest stamen number in the order Zingiberales. The molecular mechanism for the asymmetric androecial petaloidy remains poorly understood. Here, we studied the identity specification in Canna stamen.
We observed four types of abnormal flower in terms of androecium identity transformation and analysed the corresponding floral symmetry changes. We further tested the expression patterns of B‐ and C‐class MADS‐box genes using in situ hybridization in normal Canna stamen.
Homeotic conversions in the androecium were accompanied by floral symmetry changes, and the asymmetric stamen is key in contributing to the floral asymmetry. Both B‐ and C‐class genes exhibited higher expression levels in the anther primordium than in other androecial parts. This asymmetric expression pattern precisely corresponded to the asymmetric identities of the Canna androecium.
We identified C. indica as a model species for studying androecial organ identity and floral symmetry synthetically in Zingiberales. We hypothesized that homeotic genes specify floral organ identity in a putative dose‐dependent manner. The results add to the current understanding of organ identity‐related floral symmetry.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.