NJ cluster analysis of the SnRK2, PYR/PYL/RCAR, and ABF genes in Tibetan hulless barley.

The abscisic acid (ABA) signaling pathway is known as one of the most important signaling pathways in plants and is mediated by multiple regulators. The genes SnRK2, PYR/PYL/RCAR, and ABF are relevant to both ABA-dependent and -independent signaling pathways. To elucidate the profile of these genes from Tibetan hulless barley (Hordeum vulgare L. var. nudum Hook. f.), we collected available sequences from RNA-Seq data, together with NCBI data from five other model plant species (Arabidopsis thaliana, Brachypodium distachyon, Oryza sativa, Populus trichocarpa, and Sorghum bicolor). Gene trees of SnRK2, PYR/PYL/RCAR, and ABF were constructed using a neighbor joining (NJ) method. For all genes, we identified a dominant group in which all six species were represented. Three, four, and five groups were found in the NJ trees of SnRK2, PYR/PYL/RCAR, and ABF, respectively. For each gene, Tibetan hulless barley was divided into three groups. Our analyses indicated that Tibetan hulless barley was associated with B. distachyon. The NJ cluster analysis also suggested that Tibetan hulless barley was affiliated with S. bicolor (SnRK2), A. thaliana (PYR/PYL/RCAR), and O. sativa (ABF). These results illustrate a diverse expression of genes SnRK2, PYR/PYL/RCAR, and ABF, and suggest a relationship among the six species studied. Collectively, our characterization of the three components of the ABA signaling pathway may contribute to improve stress tolerance in Tibetan hulless barley.