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Article|27 Jul 2022|OPEN
Modular regulation of floral traits by a PRE1 homolog in Mimulus verbenaceus: implications for the role of pleiotropy in floral integration
Hongfei Chen1 , ,† , Zheng Xiao1,2 ,† , Baoqing Ding1,3 , Pamela K. Diggle1 , Yao-Wu Yuan,1,4 ,
1Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
2School of Landscape Architecture, Zhejiang A&F University, Hangzhou 311300, China
3College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
4Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA
*Corresponding author. E-mail:,
Both authors contributed equally to the study.

Horticulture Research 9,
Article number: uhac168 (2022)
Views: 79

Received: 04 May 2022
Accepted: 18 Jul 2022
Published online: 27 Jul 2022


Floral traits often show correlated variation within and among species. For species with fused petals, strong correlations among corolla tube, stamen, and pistil length are particularly prevalent, and these three traits are considered an intra-floral functional module. Pleiotropy has long been implicated in such modular integration of floral traits, but empirical evidence based on actual gene function is scarce. We tested the role of pleiotropy in the expression of intra-floral modularity in the monkeyflower species Mimulus verbenaceus by transgenic manipulation of a homolog of Arabidopsis PRE1. Downregulation of MvPRE1 by RNA interference resulted in simultaneous decreases in the lengths of corolla tube, petal lobe, stamen, and pistil, but little change in calyx and leaf lengths or organ width. Overexpression of MvPRE1 caused increased corolla tube and stamen lengths, with little effect on other floral traits. Our results suggest that genes like MvPRE1 can indeed regulate multiple floral traits in a functional module but meanwhile have little effect on other modules, and that pleiotropic effects of these genes may have played an important role in the evolution of floral integration and intra-floral modularity.