Rapid Generation and Analysis of a Barley Doubled Haploid Line with Higher Nitrogen Use Efficiency Than Parental Lines by F1 Microspore Embryogenesis.

Hongwei Xu,Guimei Guo,Ruiju Lu,Zhiwei Chen,Rugen Xu,Runhong Gao,Yingbo Li,Chenghong Liu,Nigel G Halford

doi:10.3390/plants10081588

Abstract

Creating varieties with high nitrogen use efficiency (NUE) is crucial for sustainable agriculture development. In this study, a superior barley doubled haploid line (named DH45) with improved NUE was produced via F1 microspore embryogenesis with three rounds of screening in different nitrogen levels by hydroponic and field experiments. The molecular mechanisms responsible for the NUE of DH45 surpassing that of its parents were investigated by RNA-seq analysis. A total of 1027 differentially expressed genes (DEGs) were identified that were up- or down-regulated in DH45 under low nitrogen conditions but showed no significant differences in the parents. GO analysis indicated that genes involved in nitrogen compound metabolic processes were significantly enriched in DH45 compared with the parents. KEGG analysis showed the MAPK signaling pathway plant to be highly enriched in DH45 relative to its parents, as well as genes involved in alanine, aspartate and glutamate metabolism, and arginine biosynthesis. In conclusion, our study revealed the potential to fix trait superiority in a line by combining crossing with F1 microspore culture technologies in future crop breeding and also identified several candidate genes that are expressed in shoots and may enable barley to cope with low-nitrogen stress.

Highlights

Global food production faces a great challenge to meet the demand of the increasing world population, which is predicted to rise to 9 billion people by 2050 [1,2]
Doubled haploid (DH) Lines Produced by a Cross Combined with F1 Isolated Microspore Culture
A homozygous barley DH line which was produced by crossing combined with microspore technologies, exhibited better performance on biomass, grain yield and nitrogen use efficiency (NUE) over its parents under low nitrogen (LN) conditions

Summary

Introduction

Global food production faces a great challenge to meet the demand of the increasing world population, which is predicted to rise to 9 billion people by 2050 [1,2]. Nitrogen fertilizer is the most important macronutrient supplied to crops to maintain high yields in most regions [4]. It has been recognized that breeding new cultivars with high nitrogen use efficiency (NUE) would be an effective way to increase crop yields under low nitrogen (LN) input for the sustainable development of agriculture [7]. Doubled haploid (DH) technology provides a valuable adjunct to plant breeding programs, as it enables the rapid generation of completely homozygous lines [11]. It has been widely used in quantitative genetics research to discover recessive, dominant, and deleterious mutations [12,13]

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