Overexpression of SQUAMOSA promoter binding protein-like 4a (NtSPL4a) alleviates Cd toxicity in Nicotiana tabacum

Wanhong Liu; Ya Yang; Yingying Hu; Xiang Peng; Linshen He; Tengfei Ma; Shunqin Zhu; Lien Xiang; Nan Chen

doi:10.1016/j.plaphy.2024.108656

Overexpression of SQUAMOSA promoter binding protein-like 4a (NtSPL4a) alleviates Cd toxicity in Nicotiana tabacum

Plant Physiol Biochem. 2024 May:210:108656. doi: 10.1016/j.plaphy.2024.108656. Epub 2024 Apr 23.

Authors

Wanhong Liu¹, Ya Yang¹, Yingying Hu¹, Xiang Peng¹, Linshen He¹, Tengfei Ma¹, Shunqin Zhu², Lien Xiang³, Nan Chen⁴

Affiliations

¹ School of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing, 401331, China.
² School of Life Science, Southwest University, Chongqing, 400715, China.
³ College of Environmental Science and Engineering, China West Normal University, Nanchong, 637009, China.
⁴ School of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing, 401331, China. Electronic address: chennan0205@cqust.edu.cn.

PMID: 38685151
DOI: 10.1016/j.plaphy.2024.108656

Abstract

Squamosa Promoter Binding Protein-Like (SPL) plays a crucial role in regulating plant development and combating stress, yet its mechanism in regulating resistance to Cd toxicity remains unclear. In this study, we cloned a nuclear-localized transcription factor, NtSPL4a, from the tobacco cultivar TN90. Transient co-expression results showed that miR156 significantly reduced the expression of NtSPL4a by binding to the 3'-UTR of its transcript. We obtained transgenic tobacco overexpressing NtSPL4a (including the 3'-UTR) and NtSPL4aΔ (lacking the 3'-UTR) through Agrobacterium-mediated genetic transformation. Compared to the wild type (WT), overexpression of NtSPL4a/NtSPL4aΔ shortened the flowering time and exhibited a more developed root system. The transgenic tobacco showed significantly reduced Cd content, being 85.1% (OE-NtSPL4a) and 46.7% (OE-NtSPL4aΔ) of WT, respectively. Moreover, the upregulation of NtSPL4a affected the mineral nutrient homeostasis in transgenic tobacco. Additionally, overexpression of NtSPL4a/NtSPL4aΔ effectively alleviated leaf chlorosis and oxidative stress induced by Cd toxicity. One possible reason is that the overexpression of NtSPL4a/NtSPL4aΔ can effectively promote the accumulation of non-enzymatic antioxidants. A comparative transcriptomic analysis was performed between transgenic tobacco and WT to further unravel the global impacts brought by NtSPL4a. The tobacco overexpressing NtSPL4a had 183 differentially expressed genes (77 upregulated, 106 downregulated), while the tobacco overexpressing NtSPL4aΔ had 594 differentially expressed genes (244 upregulated, 350 downregulated) compared to WT. These differentially expressed genes mainly included transcription factors, metal transport proteins, flavonoid biosynthesis pathway genes, and plant stress-related genes. Our study provides new insights into the role of the transcript factor SPL in regulating Cd tolerance.

Keywords: Cadmium tolerance; Nicotiana tabacum; NtSPL4a; Transcriptome analysis; miR156.

MeSH terms

Cadmium* / metabolism
Cadmium* / toxicity
Gene Expression Regulation, Plant*
Nicotiana* / drug effects
Nicotiana* / genetics
Nicotiana* / metabolism
Plant Proteins* / genetics
Plant Proteins* / metabolism
Plants, Genetically Modified*
Transcription Factors / genetics
Transcription Factors / metabolism

Substances

Cadmium
Plant Proteins
Transcription Factors