3 Biotech

, 9:394 | Cite as

Identification of the metallothionein gene family from cucumber and functional characterization of CsMT4 in Escherichia coli under salinity and osmotic stress

  • Yong Zhou
  • Jialin Liu
  • Shiqiang Liu
  • Lunwei Jiang
  • Lifang HuEmail author
Original Article


Metallothionein (MT) proteins are low-molecular-weight, cysteine-rich and metal-binding proteins that play important roles in the maintenance of metal homeostasis and detoxification, but their roles in abiotic stress tolerance remain largely unknown. In this study, three MT family genes (CsMT2, CsMT3 and CsMT4) were identified in the cucumber genome. CsMT2, CsMT3 and CsMT4 possessed 14, 10, and 18 Cys residues, which were clustered into 2, 2, and 3 Cys-rich regions, respectively. Phylogenetic analysis of MTs from cucumber, Arabidopsis and soybean revealed that these MTs were clustered into four groups in accordance with the MT types (types 1–4). An analysis of the cis-acting regulatory elements revealed that a series of hormone-, stress-, and development-related cis-elements were present in the promoter regions of CsMT genes. Expression pattern analysis by RT-PCR showed that the CsMT genes exhibited different tissue expression patterns. CsMT2 showed relatively higher expression in stem, leaf, and flower; CsMT3 was mainly expressed in leaf, flower, and fruit, while CsMT4 was highly expressed in fruit and leaf. The qRT-PCR results showed that the CsMT genes were induced by various stress treatments including NaCl, PEG, and ABA, while CsMT4 displayed much higher expression levels in response to these stresses than CsMT2 and CsMT3. Escherichia coli cells expressing CsMT4 exhibited higher salinity and osmotic tolerance compared with control cells, indicating the significant function of CsMT4 to confer tolerance to these stresses. These results lay a foundation for further research on the function of MT family genes in plant stress responses.


Cucumber Metallothionein (MT) Abiotic stress Phylogenetic analysis Expression analysis Escherichia coli 



This work was supported by the Key Project of Youth Science Foundation of Jiangxi Province (20171ACB21025 and 20181ACB20012), the National Natural Science Foundation of China (31660385).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

13205_2019_1929_MOESM1_ESM.tif (134 kb)
Fig. S1. Gene structures of the CsMT genes. The gene structures were determined by aligning the CDS sequences with the corresponding gDNA sequences with the GSDS server. UTRs (untranslated regions), CDSs, and introns showed by green rectangles, blue rectangles, and lines, respectively (TIFF 133 kb)
13205_2019_1929_MOESM2_ESM.doc (50 kb)
Supplementary material 2 (DOC 50 kb)
13205_2019_1929_MOESM3_ESM.doc (46 kb)
Supplementary material 3 (DOC 46 kb)
13205_2019_1929_MOESM4_ESM.xls (35 kb)
Supplementary material 4 (XLS 35 kb)


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Copyright information

© King Abdulaziz City for Science and Technology 2019

Authors and Affiliations

  • Yong Zhou
    • 1
    • 2
    • 3
  • Jialin Liu
    • 1
    • 4
  • Shiqiang Liu
    • 2
    • 3
  • Lunwei Jiang
    • 3
  • Lifang Hu
    • 1
    • 4
    Email author
  1. 1.Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of EducationJiangxi Agricultural UniversityNanchangChina
  2. 2.College of ScienceJiangxi Agricultural UniversityNanchangChina
  3. 3.Institute of Biotechnology and Physical Agricultural EngineeringJiangxi Agricultural UniversityNanchangChina
  4. 4.College of AgronomyJiangxi Agricultural UniversityNanchangChina

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