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Zhang H, Xue F, Guo L, Cheng J, Jabbour F, DuPasquier PE, Xie Y, Zhang P, Wu Y, Duan X, Kong H, Zhang R. The mechanism underlying asymmetric bending of lateral petals in Delphinium (Ranunculaceae). Curr Biol 2024; 34:755-768.e4. [PMID: 38272029 DOI: 10.1016/j.cub.2024.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/13/2023] [Accepted: 01/02/2024] [Indexed: 01/27/2024]
Abstract
During the process of flower opening, most petals move downward in the direction of the pedicel (i.e., epinastic movement). In most Delphinium flowers, however, their two lateral petals display a very peculiar movement, the mirrored helical rotation, which requires the twist of the petal stalk. However, in some lineages, their lateral petals also exhibit asymmetric bending that increases the degree of mirrored helical rotation, facilitating the formation of a 3D final shape. Notably, petal asymmetric bending is a novel trait that has not been noticed yet, so its morphological nature, developmental process, and molecular mechanisms remain largely unknown. Here, by using D. anthriscifolium as a model, we determined that petal asymmetric bending was caused by the localized expansion of cell width, accompanied by the specialized array of cell wall nano-structure, on the adaxial epidermis. Digital gene analyses, gene expression, and functional studies revealed that a class I homeodomain-leucine zipper family transcription factor gene, DeanLATE MERISTEM IDENTITY1 (DeanLMI1), contributes to petal asymmetric bending; knockdown of it led to the formation of explanate 2D petals. Specifically, DeanLMI1 promotes cell expansion in width and influences the arrangement of cell wall nano-structure on the localized adaxial epidermis. These results not only provide a comprehensive portrait of petal asymmetric bending for the first time but also shed some new insights into the mechanisms of flower opening and helical movement in plants.
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Affiliation(s)
- Hanghang Zhang
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Fang Xue
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Liping Guo
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jie Cheng
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; China National Botanical Garden, Beijing 100093, China; Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Colney Lane, Norwich NR4 7UH, UK
| | - Florian Jabbour
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Paris 75005, France
| | | | - Yanru Xie
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Peng Zhang
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yijia Wu
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xiaoshan Duan
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Hongzhi Kong
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; China National Botanical Garden, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rui Zhang
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China.
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