Acta Agriculturae Boreali-Sinica ›› 2025, Vol. 40 ›› Issue (3): 19-26. doi: 10.7668/hbnxb.20195314

Special Issue: Drought and water saving Biotechnology

• Crop Genetics & Breeding·Germplasm Resources. Biotechnology • Previous Articles     Next Articles

Heterologous Expression of Ramie Metallothionein BnMLP2 Gene Enhances Arabidopsis Tolerance to Drought Stress

WANG Liqi, ZHANG Lei, LI Xi, GUAN Sheng, LU Jianning, XU Mingzhi, CUI Guoxian , SHE Wei   

  1. College of Agriculture, Ramie Research Institute, Hunan Agricultural University, Changsha 410128, China
  • Received:2024-10-23 Published:2025-06-28

Abstract:

To investigate the role of the BnMLP2 gene in drought tolerance in ramie,the BnMLP2 gene encoding a metallothionein-like protein in ramie was obtained by analyzing ramie transcriptome data using Zhongzhu-1 as the material.The BnMLP2 gene was screened and cloned from the ramie transcriptome data,and bioinformatics analyses were conducted,including sequence alignment,domain prediction,and subcellular localization prediction.Fluorescent Quantitative PCR was used to determine the expression profile of the BnMLP2 gene in different tissues of ramie and to explore its expression changes under drought stress.The BnMLP2 gene was introduced into Arabidopsis thaliana to construct transgenic plants.Under drought stress conditions,phenotypic,physiological,and biochemical differences between transgenic and wild-type Arabidopsis were compared,along with the expression of stress-related genes.The results showed that the open reading frame of the BnMLP2 gene in ramie was 243 bp in length,encoding 80 amino acids.BnMLP2 had the closest amino acid sequence homology to metallothionein(MT)or metallothionein-like protein (MLP) from Malus domestica,both belonging to the metallothionein family; it contained the PFAM01439 domain and belonged to class Ⅱ metallothionein,with a predicted subcellular localization in the cytoplasm.The BnMLP2 gene was expressed in all tissues of ramie,and its expression was significantly induced by drought,especially in stems.Under drought stress,transgenic Arabidopsis overexpressing BnMLP2 exhibited stronger drought tolerance compared to wild-type plants,as evidenced by significantly increased root length and fresh weight,enhanced antioxidant enzyme and γ-glutamylcysteine ligase (γ-GCL) activities,and accumulation of more proline (Pro),glutathione(GSH),glutathione disulfide (GSSG),and phytochelatins (PCs) to regulate intracellular ion homeostasis.The contents of malondialdehyde (MDA)and hydrogen peroxide (H2O2)in transgenic lines were significantly lower than in wild-type plants,at 55% and 80% of wild-type levels,respectively.In addition, the content of sodium and potassium ions in transgenic Arabidopsis under drought conditions was 4.4 times and 1.4 times higher than that of the wild type, respectively. Overexpression of BnMLP2 induced increased expression of three stress-related genes,AtMT1a,AtNCED3,and AtWRKY40,with maximum expression levels of 1.5,1.9,and 2.8 times those in wild-type plants,respectively.These results suggest that the BnMLP2 gene enhances the tolerance of Arabidopsis to drought stress.

Key words: Boehmeria nivea, Metallothionein, Drought stress, Tolerance, Heterologous expression

CLC Number: 

Cite this article

WANG Liqi, ZHANG Lei, LI Xi, GUAN Sheng, LU Jianning, XU Mingzhi, CUI Guoxian, SHE Wei. Heterologous Expression of Ramie Metallothionein BnMLP2 Gene Enhances Arabidopsis Tolerance to Drought Stress[J]. Acta Agriculturae Boreali-Sinica, 2025, 40(3): 19-26. doi: 10.7668/hbnxb.20195314.

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