Abstract Detail

Development and Structure

Zhang, Jingbo [1], Lee, Aaron [2], Srivastav, Mansa [3], Basu, Adreeja [4], Tong, Jingjing [5], Clement, Wendy [6], Donoghue, Michael [7], Howarth, Dianella G. [8].

Expression of CUC genes in the fused organs of Lonicera.

The organ fusion has played a key role in the origin and subsequent diversification of flowering plants, by the evolution of parts such as the fully closed carpels of angiosperms, the sympetalous corolla in asterids, and the gynostemium in the species-rich Orchidaceae. The CUP SHAPED COTYLEDON (CUC) genes of the NAC transcription factor family, consisting of two paralogs as CUC1/2 (or NAM) and CUC3 across the angiosperms, have been shown to affect the boundary formation in cotyledons, leaves, and floral organs. Honeysuckles (Lonicera, Caprifoliaceae) exhibit multiple examples of organ fusion phenomenon, such as perfoliate leaves, cupules derived from fused bracteoles, and fused ovaries. Our recent study on the evolution of CUC genes in Caprifoliaceae indicated that CUC3 has likely been lost in Lonicera, and that CUC1/2 has been duplicated into two copies (CUC2a and CUC2b). Here, we investigate the expression patterns of CUC1/2 genes in the reproductive and vegetative organs of four Lonicera species, i.e., L. sempervirens, L. periclymenum, L. japonica, and L. fragrantissima. Our preliminary qPCR results indicate that CUC2b has lower expressions in the perfoliate leaves of L. sempervirens than in the unfused leaves of L. periclymenum, which suggests that CUC2b might be involved in leaf fusion of Lonicera. Furthermore, compared to the floral buds of L. fragrantissima where paired flowers fuse at the bottom of ovaries, higher expressions of CUC2a and CUC2b were detected in the unfused floral buds of L. japonica. This result shows that the expression of CUC1/2 genes may impede the fusion of floral bud in Lonicera. Furthermore, the longer corolla tube of L. japonica may also suggest that CUC1/2 genes possibly promote the elongation of the corolla tube. A similar function of CUC genes has been noted in the previous studies in the flowers of Antirrhinum, Mimulus, and Linaria. The ongoing qPCR performed with organ tissues from different developmental stages of more Lonicera species will further characterize the expression patterns and functions of the CUC1/2 in this genus.

1 - St John's University, Biological Sciences, 8000 Utopia Parkway, Queens, NY, 11439, USA
2 - University of Minnesota, Twin Cities, Department of Plant and Microbial Biology, 712 Biological Sciences, 1445 Gortner Avenue, Saint Paul, MN, 55108, USA
3 - Yale University, Ecology And Evolutionary Biology, 21 Sachem Street, Room 364 New Haven, CT 06511, Environmental Science Center, Room Number 356, New Haven, CT, 06511, United States
4 - St. John's University, New York, 8000 Utopia Parkway, Jamaica, New York, 11439, United States
5 - St. John's University, Biological Sciences, 8000 Utopia Pkwy, Jamaica, NY, 11439, United States
6 - The College Of New Jersery, Dept. Of Biology, 2000 Pennington Road, Ewing, NJ, 08628, United States
7 - Yale University, Department Of Ecology And Evolutionary Biology, 21 Sachem St., New Haven, CT, 06511, United States
8 - St. John's University, Department Of Biological Sciences, St. Albert Hall Rm 257, 8000 Utopia Pkwy, Jamiaca, NY, 11439, United States

Keywords:
CUC1/2  genes
gene expression
gene function
Lonicera
NAC transcription factor family
organ fusion.

Presentation Type: Oral Paper
Session: DS2, Development and Structure II
Location: /
Date: Wednesday, July 21st, 2021
Time: 11:15 AM(EDT)
Number: DS2006
Abstract ID:985
Candidate for Awards:None