LaZAT9 and LaZAT10 confer resistance to Botrytis elliptica in lily by modulating ROS via glutathione metabolism.

Gray mold caused by Botrytis elliptica (B. elliptica) is a devastating disease in lily production. It is essential to identify resistant germplasm and elucidate the underlying resistance mechanisms for effective disease control in lily. In this study, we evaluated the resistance of different lily germplasms to gray mold and selected the highly resistant Lilium 'Golden Stone' (LGS) and the highly susceptible Lilium leichtlinii var. maximowiczii (LLM). After infection with B. elliptica, LGS exhibited significantly increased antioxidant enzyme activities and marked enrichment of the glutathione metabolism pathway. From this, two glutathione S-transferase genes, LaGSTU8 and LaGSTU17, were identified, which were specifically highly expressed in LGS. Silencing LaGSTU8 or LaGSTU17 led to a significant reduction in disease resistance and massive accumulation of reactive oxygen species (ROS) in LGS. Further investigation revealed that LaZAT9 and LaZAT10 directly bind to and activate the transcription of LaGSTU8 and LaGSTU17, thereby reinforcing the glutathione metabolism pathway to efficiently scavenge excess ROS, maintain redox homeostasis, and enhance lily resistance to B. elliptica. Our study provides new insights into the roles of the transcription factors LaZAT9 and LaZAT10 in plant disease resistance, enriches the molecular network of fungal disease resistance in plants, and may facilitate the breeding of broad-spectrum disease-resistant bulbous crops.