Comparative study of the genetic basis of nitrogen use efficiency in wild and cultivated barley

Jawad Munawar Shah; Sidra Tul Muntaha; Essa Ali; Azhar Abbas Khan; Syed Hassan Raza Zaidi; Ahmad Naeem Shahzad; Zeshan Hassan; Ahmad Nawaz; Muhammad Rashid; Syed Asad Hussain Bukhari

doi:10.1007/s12298-019-00714-z

Comparative study of the genetic basis of nitrogen use efficiency in wild and cultivated barley

Physiol Mol Biol Plants. 2019 Nov;25(6):1435-1444. doi: 10.1007/s12298-019-00714-z. Epub 2019 Sep 27.

Authors

Affiliations

¹ 1College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, 310058 People's Republic of China.
² College of Agriculture, Bahaudin Zakaria University, Bahadur sub Campus, Layyah, Pakistan.
³ 3Zhejiang University of Technology, Hangzhou, People's Republic of China.
⁴ 4Department of Agronomy, Bahauddin Zakariya University, Multan, 60800 Pakistan.
⁵ Department of Agronomy, Lasbella University of Agriculture, Water and Marine Sciences, Uthal, Lasbella, Pakistan.

Abstract

To curb the increasing demand for nitrogenous fertilizers, it is imperative to develop new cultivars with comparatively greater nitrogen use efficiency (NUE). Nonetheless, so far very meager information is available concerning the variances among barley (Hordeum vulgare L.) varieties for their response to nitrogen deprivation. The current study was carried out to explore the potential of barley genotypes for higher NUE. A hydroponic experiment was conducted at seedling stage to compare the performance of four barley genotypes, ZD9 and XZ149 (with higher NUE) and HXRL and XZ56 (with lower NUE) in response to low (0.1 mM) and normal nitrogen (2 mM) levels. Under low N, all the genotypes expressed less number of tillers, decreased soluble proteins, chlorophyll and N concentrations in both roots and shoots, in comparison with normal N supply. However, significant differences were found among the genotypes. The genotypes with high NUE (ZD9 and XZ149) showed higher N concentration, increased number of tillers, improved chlorophyll and soluble proteins in both roots and shoots as compared to the inefficient ones (HXRL and XZ56). Furthermore, nitrate transporter gene (NRT2.1) showed higher expression under low N, both in roots and leaves of N efficient genotypes, as compared to the N inefficient ones. However, N assimilatory genes (GS1 and GS2) showed higher expression under normal and low N level, in leaves and roots respectively. The outcome of the study revealed that genotypes with higher NUE (ZD9 and XZ149) performed better under reduced N supply, and may require relatively less N fertilizer for normal growth and development, as compared to those with lower NUE. The study also revealed a time-specific expression pattern of studied genes, indicating the duration of low N stress. The current study suggested that future work must involve the time course as a key factor while studying expression patterns of these genes to better understand the genetic basis of low-N tolerance.

Keywords: Barley; Gene expression; Nitrogen metabolism.