Abstract:In order to explore the molecular mechanism of NBSLRR genes in hulless barley(Hordeum vulgare L. var. nudum)resistance to barley leaf stripe, in this study, we isolated HvtRGA gene from leaves of the striperesistant hulless barley variety ‘Kunlun 14’ and the susceptible variety ‘Z1141’ and obtained a 3 544 bp sequence. HvtRGA gene contained a 3 306 bp open reading frame (ORF), encoding 1 101 amino acids. After sequencing and comparison, it was found that the similarity of base sequences of ‘Kunlun 14’ and ‘Z1141’ was 99.89% since the bases of ‘Z1141’ were replaced from G to A at position of 1196 and 1945, whereas the similarity of amino acid was 100%. Protein sequence analysis showed that HvtRGA was a hydrophilic unstable acidic protein containing NBARC conserved domain and five LRR domains, belonging to the NBSLRR family. The amino acid sequence similarity between HvtRGA protein and the NBSLRR encoded by rgaS9217 and rgaS226 of barley were 96.55% and 88.72%. Phylogenetic tree analysis showed that NBSLRR of hulless barley and barley of the wheat family, durum wheat, Brachypodium distachyon were clustered into one branch. Moreover, HvtRGA has the closest genetic relationship with the barley rgas9217 encoded protein, followed by the barley rgas226 encoded protein, while far away from Setaria viridis and Setaria italica. Quantitative PCR results showed that, under the stress of barley leaf stripe, the expression levels of HvtRGA gene in resistant and susceptible varieties were extremely significantly increased, and the gene expression levels in resistant varieties‘Kunlun 14’ were significantly higher than that in susceptible varieties‘Z1141’. It is speculated that HvtRGA gene may play an important role in the regulation of barley leaf stripe in hulless barley.