Open Access

ARTICLE

Brassinosteroid Biosynthetic Gene CmDWF4 Regulates Bud Outgrowth in Chrysanthemum morifolium

Xianrong Fu, Aiping Song, Bo Peng, Song Li, Weixin Liu, Lingling Zhang, Jiafu Jiang, Sumei Chen, Fadi Chen^*

State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Key Laboratory of Landscaping, Key Laboratory of Flower Biology and Germplasm Innovation (South), Ministry of Agriculture and Rural Affairs, Key Laboratory of Biology of Ornamental Plants in East China, National Forestry and Grassland Administration, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China

* Corresponding Author: Fadi Chen. Email:

(This article belongs to the Special Issue: Advances in Molecular Genetics and Physiology towards a Better Understanding of Agricultural Crop Plants)

Phyton-International Journal of Experimental Botany 2023, 92(6), 1681-1694. https://doi.org/10.32604/phyton.2023.027870

Received 18 November 2022; Accepted 20 February 2023; Issue published 11 April 2023

Abstract

Brassinosteroids (BRs), a class of steroid phytohormones, play a critical role in plant growth and development. The DWF4 gene encodes a cytochrome P450 enzyme (CYP90B1), which is considered a rate-limiting enzyme in BR biosynthesis. Here, we identified a homologous gene of DWF4 in chrysanthemum, CmDWF4. This gene was predicted to encode 491 amino acid residues with a molecular weight of 56.2 kDa and an isoelectric point (pI) of 9.10. Overexpression of CmDWF4 in chrysanthemum was found to significantly increase growth rate, number, and length of lateral buds. Transcriptome analysis showed that multiple xyloglucan endotransglycosylase/hydrolase (XTH) family encoding genes associated with cell wall modification were up-regulated in CmDWF4-overexpressing lines. qRT-PCR assay confirmed the up-regulation of CmXTH6, CmXTH23, and CmXTH28 in CmDWF4-overexpression line. Overall, this work establishes a mechanism by which BR biosynthetic gene CmDWF4 promotes lateral bud outgrowth in chrysanthemum, possibly through regulating cell elongation and expansion.

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