Overexpression of AtPAD4 in transgenic Brachypodium distachyon enhances resistance to Puccinia brachypodii

Brachypodium distachyon (L.) has recently emerged as a model for temperate grasses for investigating the molecular basis of plant–pathogen interactions. Phytoalexin deficient 4 ( PAD 4 ) plays a regulatory role in mediating expression of genes involved in plant defence. In this research, we generated transgenic B. distachyon plants constitutively overexpressing At PAD 4 . Two transgenic B. distachyon lines were verified using PCR and GUS phenotype. Constitutive expression of At PAD 4 in B. distachyon enhanced resistance to Puccinia brachypodii . P .  brachypodii generated less urediniospores on transgenic than on wild‐type plants. At PAD 4 overexpression enhanced salicylic acid ( SA ) levels in B. distachyon ‐infected tissues. qRT ‐ PCR showed that expression of pathogenesis‐related 1 ( PR1 ) and other defence‐related genes were up‐regulated in transformed B. distachyon following infection with P. brachypodii . Our results indicate that At PAD 4 overexpression in B. distachyon plants led to SA accumulation and induced PR gene expression that reduced the rate of colonisation by P. brachypodii .