REXO4 and infection: We next focussed on the characterisation of four RXLR effectors upregulated during infection (Additional file 3: Figure S5) and named them REX1 (PLTG_01927 [GenBank:KX130348]), REX2 (PLTG_00715 [GenBank:KX130350]), REX3 (PLTG_00687 [GenBank:KX130351]) and REX4 (PLTG_13723 [GenBank:KX130352]).