Rapid Generation of Barley Homozygous Transgenic Lines Based on Microspore Culture: HvPR1 Overexpression as an Example.

Obtaining homozygous lines from transgenic plants is an important step for phenotypic evaluations, but the selection of homozygous plants is time-consuming and laborious. The process would be significantly shortened if anther or microspore culture could be completed in one generation. In this study, we obtained 24 homozygous doubled haploid (DH) transgenic plants entirely by microspore culture from one T transgenic plant overexpressing the gene (pathogenesis-related-1). Nine of the doubled haploids grew to maturity and produced seeds. qRCR (quantitative real-time PCR) validation showed that the HvPR1 gene was expressed differentially even among different DH plants (T) from the same DH line (T). Phenotyping analysis suggested that the overexpression of inhibited nitrogen use efficiency (NUE) only under low nitrogen treatment. The established method of producing homozygous transgenic lines will enable the rapid evaluation of transgenic lines for gene function studies and trait evaluation. As an example, the overexpression of DH lines also could be used for further analysis of NUE-related research in barley.