Expression Analysis of Nitrogen Metabolism-Related Genes Reveals Differences in Adaptation to Low-Nitrogen Stress between Two Different Barley Cultivars at Seedling Stage.

Zhiwei Chen,Jianhua Huang,Runhong Gao,Hongwei Xu,Ruiju Lu,Yingbo Li,Chenghong Liu,Yifei Wang,Ting He,Longhua Zhou,Guimei Guo

doi:10.1155/2018/8152860

Zhiwei Chen, Jianhua Huang + Show 9 more

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https://doi.org/10.1155/2018/8152860

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Abstract

The excess use of nitrogen fertilizers causes many problems, including higher costs of crop production, lower nitrogen use efficiency, and environmental damage. Crop breeding for low-nitrogen tolerance, especially molecular breeding, has become the major route to solving these issues. Therefore, in crops such as barley (Hordeum vulgare L.), it is crucial to understand the mechanisms of low-nitrogen tolerance at the molecule level. In the present study, two barley cultivars, BI-04 (tolerant to low nitrogen) and BI-45 (sensitive to low nitrogen), were used for gene expression analysis under low-nitrogen stress, including 10 genes related to primary nitrogen metabolism. The results showed that the expressions of HvNIA2 (nitrite reductase), HvGS2 (chloroplastic glutamine synthetase), and HvGLU2 (ferredoxin-dependent glutamate synthase) were only induced in shoots of BI-04 under low-nitrogen stress, HvGLU2 was also only induced in roots of BI-04, and HvGS2 showed a rapid response to low-nitrogen stress in the roots of BI-04. The expression of HvASN1 (asparagine synthetase) was reduced in both cultivars, but it showed a lower reduction in the shoots of BI-04. In addition, gene expression and regulation differences in the shoots and roots were also compared between the barley cultivars. Taken together, the results indicated that the four above-mentioned genes might play important roles in low-nitrogen tolerance in barley.

Highlights

Nitrogen, one of the essential elements for crop growth and development, is a primary driver of crop production
There was no significant difference in shoot dry weight of BI-04 between normal nitrogen supply and lownitrogen stress, while there was a significant difference in BI-45 (P < 0 05), and there were no significant differences in root dry weight of the two barley cultivars between normal nitrogen supply and low-nitrogen stress (Figures 1(c) and 1(d))
The results indicated that the responses to lownitrogen stress were different between BI-04 and BI-45 and that BI-04 was more tolerant to low-nitrogen stress than BI-45

Summary

Introduction

One of the essential elements for crop growth and development, is a primary driver of crop production. There is a consensus among plant and environmental scientists that it is important to balance the benefits of nitrogen application, mainly increased yield, against its disadvantages, and to minimize negative impacts by decreasing nitrogen fertilizer input and environmental pollution, while maintaining yields. Increasing nitrogen use efficiency or developing crops with the ability to tolerate low-nitrogen are important targets for future crop breeding [2]. Achieving these targets will require a comprehensive understanding of nitrogen metabolism under low-nitrogen condition, the expression of genes involved in the adaptation to, or tolerance of, low-nitrogen stress

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