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Int J Mol Sci. 2019 Jun 12;20(12). pii: E2871. doi: 10.3390/ijms20122871.

Overexpression of a Metallothionein 2A Gene from Date Palm Confers Abiotic Stress Tolerance to Yeast and Arabidopsis thaliana.

Author information

1
Department of Biology, College of Sciences, Sultan Qaboos University, P.O. Box 36, 123 Muscat, Oman. himanshu30@gmail.com.
2
Department of Biology, College of Sciences, Sultan Qaboos University, P.O. Box 36, 123 Muscat, Oman. i.alharrasi@gmail.com.
3
Department of Biology, College of Sciences, Sultan Qaboos University, P.O. Box 36, 123 Muscat, Oman. latifakharusi@gmail.com.
4
Department of Biology, College of Sciences, Sultan Qaboos University, P.O. Box 36, 123 Muscat, Oman. gerryjana@gmail.com.
5
Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, P.O. Box 34, 123 Muscat, Oman. alyahyai@squ.edu.om.
6
Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA. ramanjulu.sunkar@okstate.edu.
7
Department of Biology, College of Sciences, Sultan Qaboos University, P.O. Box 36, 123 Muscat, Oman. myaish@squ.edu.om.

Abstract

Although the date palm tree is an extremophile with tolerance to drought and certain levels of salinity, the damage caused by extreme salt concentrations in the soil, has created a need to explore stress-responsive traits and decode their mechanisms. Metallothioneins (MTs) are low-molecular-weight cysteine-rich proteins that are known to play a role in decreasing oxidative damage during abiotic stress conditions. Our previous study identified date palm metallothionein 2A (PdMT2A) as a salt-responsive gene, which has been functionally characterized in yeast and Arabidopsis in this study. The recombinant PdMT2A protein produced in Escherichia coli showed high reactivity against the substrate 5'-dithiobis-2-nitrobenzoic acid (DTNB), implying that the protein has the property of scavenging reactive oxygen species (ROS). Heterologous overexpression of PdMT2A in yeast (Saccharomyces cerevisiae) conferred tolerance to drought, salinity and oxidative stresses. The PdMT2A gene was also overexpressed in Arabidopsis, to assess its stress protective function in planta. Compared to the wild-type control, the transgenic plants accumulated less Na+ and maintained a high K+/Na+ ratio, which could be attributed to the regulatory role of the transgene on transporters such as HKT, as demonstrated by qPCR assay. In addition, transgenic lines exhibited higher chlorophyll content, higher superoxide dismutase (SOD) activity and improved scavenging ability for reactive oxygen species (ROS), coupled with a better survival rate during salt stress conditions. Similarly, the transgenic plants also displayed better drought and oxidative stress tolerance. Collectively, both in vitro and in planta studies revealed a role for PdMT2A in salt, drought, and oxidative stress tolerance.

KEYWORDS:

abiotic stress; date palm; drought; functional characterization; metallothionein; salinity

PMID:
31212812
PMCID:
PMC6627811
DOI:
10.3390/ijms20122871
[Indexed for MEDLINE]
Free PMC Article

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