Rapid Generation of Barley Mutant Lines With High Nitrogen Uptake Efficiency by Microspore Mutagenesis and Field Screening

Abstract

In vitro mutagenesis via isolated microspore culture provides an efficient way to produce numerous double haploid (DH) lines with mutation introduction and homozygosity stabilization, which can be used for screening directly. In this study, 356 DH lines were produced from the malt barley (Hordeum vulgare L.) cultivar Hua-30 via microspore mutagenic treatment with ethyl methane sulfonate or pingyangmycin during in vitro culture. The lines were subjected to field screening under high nitrogen (HN) and low nitrogen (LN) conditions, and the number of productive tillers was used as the main screening index. Five mutant lines (A1-28, A1-84, A1-226, A16-11, and A9-29) with high numbers of productive tillers were obtained over three consecutive years of screening. In the fifth year, components related to N-use efficiency (NUE), including N accumulation, utilization, and translocation, were characterized for these lines based on N uptake efficiency (NUpE), N utilization efficiency (NUtE), and N translocation efficiency (NTE). The results show that the NUpE of four mutant lines (A1-84, A1-226, A9-29, and A16-11) improved significantly under HN, whereas that of two lines (A1-84 and A9-29) improved under LN. As a result, their NUE improved greatly. No improvement in NUtE was observed in any of the five mutant lines. A1-84 and A9-29 were selected as an enhanced genotype in N uptake, and A1-28 showed improved NTE at the grain-filling stage. Our results imply that high-NUpE mutants can be produced through microspore mutagenesis and field screening, and that improvement of NUE in barley depends on enhancement of N uptake.

Comparative Analysis of Morphology, Photosynthetic Physiology, and Transcriptome Between Diploid and Tetraploid Barley Derived From Microspore Culture

“…The double haploid and tetraploid barley were obtained from a microspore culture of the barley cultivar “H30,” which is the one primarily used in China’s Shanghai region for malt barley production ( Chen et al, 2012 ; Gao et al, 2018 ). The plant growth conditions of these barley plants are detailed by Xu et al (2016) .…”

“…Barley ( H. vulgare L.), a worldwide staple crop, has been used for food, feed, brewing, and health products ( Newman and Newman, 2006 ; Gao et al, 2018 ). Due to its high frequency of embryogenesis, barley has also been thought of as an excellent model plant for breading double haploids ( Lu et al, 2008 ).…”

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

“…Two nitrogen regimes (150 kg ha −1 and 45 kg ha −1 ) were applied to screen the DH lines in the growing seasons of 2016–2019. The details of soil type and nitrogen application were as described previously [ 15 ]. Relative values of grain yield were calculated as grain yield under the low nitrogen (LN) condition/grain yield under the control condition (CK).…”

“…Microspores are immature precursors to pollen grains, which are not interfered with by heterozygous diploid somatic cells from anther wall tissues and also have higher embryogenesis efficiency [ 10 ]. Thus far, although there has been some work on microspore mutagenesis breeding technology for improving NUE [ 15 ], little attention has been paid to applying crossing combined with isolated F1 microspore culture technology to rapidly generate DH lines with higher NUE than their parents. In comparison with the offspring from conventional hybridization, the progeny of DH lines are more stable and reliable for NUE evaluation.…”

“…Barley ( Hordeum vulgare L.) is the world’s fourth most important cereal crop after wheat, rice, and maize, and it has been recognized as an excellent model plant for microspore embryogenesis and functional food research [ 15 , 16 , 17 , 18 ]. The objective of this study was to rapidly generate barley DH lines with higher nitrogen use efficiency than parental lines by F1 microspore embryogenesis and explore the molecular mechanism for improving NUE by genome-wide transcriptomic profiling.…”