The Wheat Bax Inhibitor-1 Protein Interacts with an Aquaporin TaPIP1 and Enhances Disease Resistance in .

Bax inhibitor-1 (BI-1) is an endoplasmic reticulum (ER)-resident cell death suppressor evolutionarily conserved in eukaryotes. The ability of BI-1 to inhibit the biotic and abiotic stresses have been well-studied in , while the functions of wheat BI-1 are largely unknown. In this study, the wheat BI-1 gene was isolated by an RNA-seq analysis of ()-treated wheat. expression was induced by a salicylic acid (SA) treatment and down-regulated by an abscisic acid (ABA) treatment. Based on β-glucuronidase (GUS) staining, was expressed in mature leaves and roots but not in the hypocotyl or young leaves. Constitutive expression of in enhanced its resistance to pv. () DC3000 infection and induced SA-related gene expression. Additionally, transgenic exhibited an alleviation of damage caused by high concentrations of SA and decreased the sensitivity to ABA. Consistent with the phenotype, the RNA-seq analysis of and Col-0 plants showed that was involved in biotic stresses. These results suggested that positively regulates SA signals and plays important roles in the response to biotic stresses. In addition, TaBI-1.1 interacted with the aquaporin TaPIP1, and both them were localized to ER membrane. Furthermore, we demonstrated that was up-regulated by SA treatment and transgenic enhanced the resistance to DC3000 infection. Thus, the interaction between TaBI-1.1 and TaPIP1 on the ER membrane probably occurs in response to SA signals and defense response.