Abstract Detail

Development and Structure

Gurung, Vandana [1], Diggle, Pamela [2], Yuan, Yaowu [3].

The curious case of CUC in corolla tube formation in Mimulus.

Morphogenesis involves formation of organs from primordia, masses of highly meristematic cells, that gives rise to diverse structures such as leaves, or floral organs (sepals, petals, stamens, and carpels). The establishment of organs requires specification of distinct boundaries; the absence of boundaries results in fusion of organs, which has been considered a critical process underlying the evolution of diverse novel forms. In over 1/3rd of angiosperm species, the petals are united to form a corolla tube, a condition known as sympetaly. Corolla tubes are thought to be a key innovation contributing to diversification of many flowering plant lineages and are a major determinant of pollinator specificity that may play a critical role in reproductive isolation. Despite its evolutionary and functional significance, our understanding of corolla tube formation is limited, in part because the model species, Arabidopsis thaliana, lacks a corolla tube. Here, we elucidate the role of a boundary specific gene, CUC, i.e., Cup Shaped Cotyledon, in the formation of the corolla tube in Mimulus. CUC has been widely studied in a few sympetalous taxa such as Petunia and Antirrhinum. However, the results are inconclusive in Petunia and the lack of experimental validation through transgenic analysis in Antirrhinum has hindered the study of CUC function in corolla tube formation. By taking advantage of transgenic tools developed for Mimulus, we manipulated the expression of CUC in M. lewisii and found that constitutive expression of the wild-type MlCUC did not affect tube formation, whereas expression of a miR164-insensitive MlCUC driven by its native promoter completely disrupted petal fusion and resulted in separation of floral organs. These compelling results provide the first experimental evidence for the critical role of the miR164-CUC regulatory module in corolla tube formation.

1 - University Of Connecticut, Department Of Ecology And Evolutionary Biology, 75 N. Eagleville Road, Unit 3043 Storrs,, Storrs, CT, 06269, United States
2 - University Of Connecticut, Department Of Ecology And Evolutionary Biology, Storrs, CT, 6269, United States
3 - University Of Connecticut, Ecology And Evolutionary Biology, 75 N. Eagleville Rd., Unit 3043, Storrs, CT, 06269, United States

Corolla tube
Genetic control
Organ boundary specification
Cup Shaped Cotyledon

Presentation Type: Oral Paper
Number: DS1001
Abstract ID:121
Candidate for Awards:Katherine Esau Award,Maynard F. Moseley Award

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