The genome of Phytophthora infestans encodes a large number of RXLR effectors that are aiming to manipulate host cellular functions in order to promote disease. PiAVR2 is an RXLR effector that was shown to interact with potato BSU1-like (BSL) ser/thr phosphatase 1 (Saunders et al., Plant cell 2012), the homolog of Arabidopsis BSL1, a positive regulator of the brassinosteroid (BR) signaling pathway controlling plant growth and development. The exploitation of the large existing -omics, genetic and material resources on BR signaling in Arabidopsis could possibly help to decipher the mechanistic basis of the mode of action of PiAVR2 and guide subsequent work in solanaceous plant species, the natural hosts of P. infestans. Using a cell-based system, we have identified a strong interaction between PiAVR2 and AtBSL1, AtBSL2 and AtBSL3 but not with AtBSU1. In further studies, we show that, although PiAVR2 interacts with BSU1-like phosphatases, it is not affecting typical BR responses such as BR-dependent activation of BES1/BZR2 transcription factor and BR- regulated gene expression. PiAVR2 also does not affect flg22-dependent early immune responses in Arabidopsis such as the oxidative burst, MAP kinase activation, or FRK1 induction. However, PiAVR2 enhances susceptibility to microbe infection in Arabidopsis and PiAVR2 plants are more sensitive to the (hemi)biotrophic pathogen Pseudomonas syringae and Phytophthora capsici but more resistant to the necrotroph Alternaria brassicicola. Future work will aim to determine how PiAVR2 impedes plant immunity through its interaction with the BSLs.
|Published - 1 Aug 2016
|Oomycete Molecular Genetics Network, Malmö, Sweden -
Duration: 15 Jun 2016 → 17 Jun 2016
|Oomycete Molecular Genetics Network, Malmö, Sweden
|15/06/16 → 17/06/16