OXS2 is Required for Salt Tolerance Mainly through Associating with Salt Inducible Genes, CA1 and Araport11, in Arabidopsis

Ying Jing,Jianwei Gao,Mei Wang,Xin Li,Wei Zhang,Lin Shi,Lilong He,Han Zheng

doi:10.1038/s41598-019-56456-1

Abstract

Salt stress is one of the abiotic stresses affecting crop growth and yield. The functional screening and mechanism investigation of the genes in response to salt stress are essential for the development of salt-tolerant crops. Here, we found that OXIDATIVE STRESS 2 (OXS2) was a salinity-induced gene, and the mutant oxs2-1 was hypersensitive to salt stress during seed germination and root elongation processes. In the absence of stress, OXS2 was predominantly localized in the cytoplasm; when the plants were treated with salt, OXS2 entered the nuclear. Further RNA-seq analysis and qPCR identification showed that, in the presence of salt stress, a large number of differentially expressed genes (DEGs) were activated, which contain BOXS2 motifs previously identified as the binding element for AtOXS2. Further ChIP analysis revealed that, under salt stress, OXS2 associated with CA1 and Araport11 directly through binding the BOXS2 containing fragments in the promoter regions. In conclusion, our results indicate that OXS2 is required for salt tolerance in Arabidopsis mainly through associating with the downstream CA1 and Araport11 directly.

Highlights

Salt tolerant crops can be achieved through two approaches
The data indicated that the abundance of the AtOXS2 mRNA increased within 1 h after the salt treatment and stayed at a high level within the following 24 h (Fig. 1), indicating that the AtOXS2 transcript is activated in response to salinity stress and may be involved in plant salinity responses
OXIDATIVE STRESS 2 (OXS2) was proved to be responsive to several types of stresses, such as ABA, cold, diamide and Cd24,25, there is no report indicating that OXS2 was involved in salt stress

Summary

Introduction

Salt tolerant crops can be achieved through two approaches. First, salt tolerant crops can be generated by normal hybridization breeding of existing salt tolerance genotypes[20,21]. Arabidopsis OXS2 and two OXS2 homolog genes from maize (ZmOXS2b and ZmO2L1) have been found to play a role in stress escape and Cd stress tolerance[24,25]. The OXS2 homologous, ZmOXS2b and ZmO2L1, can confer Cd tolerance when heterogeneously expressed in Arabidopsis by activating the promoter of Cd-Inducible Methyltransferase 1 (CIMT 1), which is expressed in root and enhances the Cd resistant ability of Arabidopsis when overexpressed alone[25]. All of these three OXS2 members are able to directly recognize segments including the CT-rich BOXS2 motif. Our findings suggest a new salt regulation mechanism, which can be potentially used for engineering salt tolerance in major crop plants

Methods

Results

Conclusion