FIG 1.
VdGAL4 can induce cell death, and the signal peptide (SP) is required for VdGAL4-induced cell death. (A) Schematics of the five GH27 proteins in V. dahliae and their domain structures. SP, signal peptide; Melibiase_C, Alpha galactosidase C-terminal beta-sandwich domain. (B) The cell death-inducing ability of GH27 proteins of V. dahliae and VdGAL4 induced cell death in Nicotiana benthamiana. The leaves of 4-week-old N. benthamiana were infiltrated with the indicated proteins. BAX and GFP were used as positive and negative controls, and the buffer was blank control (infected fluid). The photographs were taken 7 days postagroinfiltration (dpa). (C) Western blot analysis of transient expression proteins of GFP and VdGAL1-5. Proteins were stained with Coomassie brilliant blue (CBB) to determine equal loading. (D) Yeast signal trap system to verify the SP functions of VdGAL4. The known functional SPs of Avr1b and Mg87 were used as positive and negative controls, respectively. (E) The removed SP of VdGAL4 (VdGAL4ΔSP) could not cause cell death in N. benthamiana. (F) Western blot analysis of transient expression proteins of GFP, VdGAL4, and VdGAL4ΔSP.