Transcription factor ApSP1 identified through ApSDR53C2 promoter screening promotes melanin biosynthesis and enhances penetration ability in Arthrinium phaeospermum
Abstract
BACKGROUND: Arthrinium phaeospermum is the main pathogen causing shoot blight in Bambusa pervariabilis × Dendrocalamopsis grandis. Its SDR gene family, particularly ApSDR53C2, plays a key role in virulence, though its upstream regulation was unclear. RESULTS: This study identified the minimal promoter region of ApSDR53C2 within the 0 to -184 bp segment and discovered the upstream transcription factor ApSP1 through yeast one-hybrid and dual-luciferase assays. Functional studies using silenced and overexpressed strains revealed that ApSP1 significantly affects fungal virulence, stress responses (oxidative, hyperosmotic, and heavy metal), and cell wall integrity. Furthermore, ApSP1 affects the ability of the strain to penetrate cellulose membranes by influencing the expression of the melanin synthesis-related genes ApCmr1 and ApLac1. CONCLUSION: These findings elucidate the upstream regulatory network of ApSDR53C2 and highlight ApSP1's multifunctional role in pathogenicity and environmental adaptation, offering insights for managing bamboo shoot blight.