Integrative Biology Journals
JIPB

J Integr Plant Biol.

• Research Article •    

RsLBD3 regulates the secondary growth of taproot by integrating auxin and cytokinin signaling in radish (Raphanus sativus L.)

Junhui Dong1,2, Yan Wang1, Liang Xu1, Bingshuang Li1, Xiaoli Zhang1, Yinglong Chen3, Jiali Ying1, Sen Chen1, Feng Cui4 and Liwang Liu1,4*   

  1. 1. National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (East China) of MOAR, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
    2. Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
    3. The UWA Institute of Agriculture, and School of Agriculture and Environment, The University of Western Australia, Perth 6009, WA, Australia
    4. College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou 225009, China

    *Correspondence: Liwang Liu (nauliulw@njau.edu.cn)
  • Received:2025-02-18 Accepted:2025-03-31 Online:2025-05-07
  • Supported by:
    This work was supported by grants from the Jiangsu Seed Industry Revitalization Project [Grant No. JBGS(2021)071], the National Natural Science Foundation of China (Grant No. 32172579), Key Technology R & D Program of Jiangsu Province (Grant No. BE2023366), the Jiangsu Agricultural S&T Innovation Fund (Grant No. CX (23)1013) and the Project Founded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).

HTML

PDF

Abstract: Radish (Raphanus sativus L.) is a globally important root vegetable crop known for its diverse varieties and unique taproot characteristics. The LBD (LATERAL ORGAN BOUNDARIES DOMAIN) gene family, specific to plants, plays a pivotal role in the development of lateral plant organs. Nonetheless, the precise biological functions and molecular regulatory mechanisms of LBD genes in radish taproot development remain largely unexplored. In this study, the RsLBD3 gene was identified as a potential candidate affecting taproot size in radish through a genome-wide association study. Further investigation revealed two insertions in the C-terminal region of RsLBD3, with insertion363 notably enhancing the transcriptional activation capability of RsLBD3. It was observed that radish taproots with RsLBD3Ins-363 haplotype displayed significantly greater length and weight compared to those with RsLBD3Del-363 haplotype. RNA in situ hybridization and reverse transcription quantitative polymerase chain reaction analysis revealed that the RsLBD3 gene exhibits high expression level in the vascular cambium and is induced by cytokinin treatment. Silencing the RsLBD3 gene resulted in the inhibition of vascular cambium activity in the taproot, thereby impeding thickening. Exogenous cytokinin treatment could partially rescue the small-taproot phenotypes caused by RsLBD3 silencing. Moreover, RsARF5 (AUXIN RESPONSE FACTOR 5), RsRR7b (RESPONSE REGULATOR 7), and RsCYCD3-1 (CYCLIN D3;1) were identified as target genes of RsLBD3. Notably, RsARF5 was found to directly regulate the expression of RsWOX4 (WUSCHEL-RELATED HOMEOBOX 4). Additionally, biochemical analysis demonstrated that RsTCP14 interacts with RsLBD3, contributing to the binding of RsLBD3 to its target genes. Collectively, these findings contribute to a better understanding of the regulatory mechanisms underlying taproot morphogenesis, and provide novel allelic variations for the genetic enhancement of taproot shape traits in radish.

Key words: cytokinin, LBD3, natural variation, radish, vascular cambium

Editorial Office, Journal of Integrative Plant Biology, Institute of Botany, CAS
No. 20 Nanxincun, Xiangshan, Beijing 100093, China
Tel: +86 10 6283 6133 Fax: +86 10 8259 2636 E-mail: jipb@ibcas.ac.cn
Copyright © 2022 by the Institute of Botany, the Chinese Academy of Sciences
Online ISSN: 1744-7909 Print ISSN: 1672-9072 CN: 11-5067/Q
备案号：京ICP备16067583号-22