The bZIP transcription factor PsBZP32 is involved in cyst germination, oxidative stress response, and pathogenicity of Phytophthora sojae

Abstract

Abstract The basic leucine zipper (bZIP) transcription factor family, one of the largest and most diverse transcription factor families in eukaryotes, is associated with the development and stress responses of many eukaryotic organisms. However, their biological functions in oomycete plant pathogens are unclear. A genome-wide analysis of bZIP transcription factors in Phytophthora sojae showed that PsBZP32, which has a unique bZIP-PAS domain structure, exhibited a high transcription level during the early stages of P. sojae infection. We silenced PsBZP32 in P. sojae and found that the transformants showed defective cyst germination and pathogenicity. The transformants could not eliminate host-derived reactive oxygen species during infection and were more sensitive to oxidative stress. Their response to oxidative stress was independent of the PsBZP32 transcription level; however, subcellular localization and phosphorylation of PsBZP32 were affected by H2O2 stress. These results indicate that PsBZP32 is involved in regulation of P. sojae cyst germination, oxidative stress response, and pathogenicity.

Keywords

• Phytophthora sojae
• bZIP transcription factor
• Cyst germination
• Oxidative stress response
• Pathogenicity
• Phosphorylation