J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (10): 2279-2291.DOI: 10.1111/jipb.13549

• Cell and Developmental Biology • Previous Articles     Next Articles

The role of Class Ⅱ KNOX family in controlling compound leaf patterning in Medicago truncatula

Xiao Wang1, Juanjuan Zhang1, Maofeng Chai2, Lu Han1, Xiaohua Cao1, Jing Zhang1, Yiming Kong3, Chunxiang Fu4, Zeng‐Yu Wang2, Kirankumar S. Mysore5, Jiangqi Wen5 and Chuanen Zhou1*   

  1. 1. The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Science, Shandong University, Qingdao 266237, China;
    2. Grassland Agri‐Husbandry Research Center, College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China;
    3. College of Life Sciences, Shandong Normal University, Jinan 250014, China;
    4. Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China;
    5. Institute of Agricultural Biosciences, Oklahoma State University, Ardmore 73401, Oklahoma, USA
    *Correspondence: Chuanen Zhou (czhou@sdu.edu.cn)
  • Received:2023-04-04 Accepted:2023-07-31 Online:2023-08-01 Published:2023-10-01

Abstract: Compound leaf development requires the coordination of genetic factors, hormones, and other signals. In this study, we explored the functions of Class Ⅱ KNOTTED-like homeobox (KNOXII) genes in the model leguminous plant Medicago truncatula. Phenotypic and genetic analyses suggest that MtKNOX4, 5 are able to repress leaflet formation, while MtKNOX3, 9, 10 are not involved in this developmental process. Further investigations have shown that MtKNOX4 represses the CK signal transduction, which is downstream of MtKNOXⅠ-mediated CK biosynthesis. Additionally, two boundary genes, FUSED COMPOUND LEAF1 (orthologue of Arabidopsis Class M KNOX) and NO APICAL MERISTEM (orthologue of Arabidopsis CUP-SHAPED COTYLEDON), are necessary for MtKNOX4-mediated compound leaf formation. These findings suggest, that among the members of MtKNOXⅡ, MtKNOX4 plays a crucial role in integrating the CK pathway and boundary regulators, providing new insights into the roles of MtKNOXⅡ in regulating the elaboration of compound leaves in M. truncatula.

Key words: KNOTTED-like homeobox, KNOXM, NAM, cytokinin, compound leaf

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