Overexpression of Acyl-CoA-Binding Protein 1 (ChACBP1) From Saline-Alkali-Tolerant Chlorella sp. Enhances Stress Tolerance in Arabidopsis.

Kun Qiao,Shenkui Liu,Min Wang,Tetsuo Takano

doi:10.3389/fpls.2018.01772

Abstract

A large proportion of the world’s arable land is saline-alkali land, and this is becoming an urgent environmental problem for agriculture. One approach to address this problem is to develop new varieties of stress-resistant plants through genetic engineering. The algae (Chlorella sp.) JB6, which was previously isolated from saline-alkali land, was found to exhibit strong NaHCO3 tolerance. Here, we explored saline-alkali-tolerance genes in this alga that might be useful for producing abiotic stress-resistant transgenic plants. We identified a gene encoding acyl-CoA-binding protein 1 (ACBP1) from JB6 by screening a full-length cDNA library in yeast under NaHCO3 stress. Northern blot analyses showed that the ChACBP1 mRNA levels were significantly up-regulated under abiotic stresses such as salinity, oxidation, heavy metals, and low temperature stresses. The recombinant ChACBP1 protein was found to bind phosphatidylcholine in vitro. Green fluorescent protein-labeled ChACBP1 was localized to the cytosol. Overexpression of ChACBP1 in yeast and Arabidopsis increased their resistance to high salinity, oxidation, heavy metals, and low temperature stresses. These results suggested that ChACBP1 may mediate plant abiotic stress adaptation through phospholipid metabolism. Thus, ChACBP1 may be useful to genetically improve the tolerance of plants to saline-alkali soil.

Highlights

Saline-alkali soil can contain different types of salts (e.g., Na2SO4, NaCl, NaHCO3)
We identified a gene encoding a small acyl-CoA-binding proteins (ACBPs) (ChACBP) from Chlorella (JB6) by screening its fulllength cDNA library expressed in yeast under NaHCO3 stress
We investigated Chlorella acyl-CoA-binding protein gene (ChACBP) expression in response to several abiotic stresses

Summary

INTRODUCTION

Saline-alkali soil can contain different types of salts (e.g., Na2SO4, NaCl, NaHCO3). Carbonate stress impairs plants in several ways by imposing ionic stress, drought stress, and oxidative stress, resulting in nutritional deficiency, metabolic disorders, and membrane damage These changes affect plant growth and development and agricultural yield. We found a species of Chlorella, JB6, in the alkaline-saline soil of northeastern China This alga was found to show extremely high tolerance to NaHCO3 and NaCl (Wang et al, 2011; Qiao et al, 2015). Transgenic yeast and Arabidopsis overexpressing ChACBP showed enhanced tolerance to salinity, oxidation, heavy metals, and low-temperature stresses. Filter-binding assays revealed that ChACBP interacted with lipids These results have clarified the molecular mechanism of ChACBP and indicate that the gene encoding this protein may be useful for generating transgenic plants resistant to saline-alkali soil

MATERIALS AND METHODS

RESULTS

Findings

DISCUSSION