Jasmonate signaling drives defense responses against Alternaria alternata in chrysanthemum

Abstract

AbstractBackground Black spot disease caused by the necrotrophic fungus Alternaria spp. is one of the most devastating diseases affectingChrysanthemum morifolium. There is currently no effective way to prevent chrysanthemum black spot. Results We revealed that pre-treatment of chrysanthemum leaves with the plant hormone jasmonate (JA) significantly reduces their susceptibility toAlternaria alternata. To understand how JA treatment induces resistance, we monitored the dynamics of metabolites and the transcriptome in leaves after JA treatment followingA. alternatainfection. JA signaling affected the resistance of plants to pathogens through cell wall modification, Ca2+regulation, reactive oxygen species (ROS) regulation, mitogen-activated protein kinase cascade and hormonal signaling processes, and the accumulation of anti-fungal and anti-oxidant metabolites. Furthermore, the expression of genes associated with these functions was verified by reverse transcription quantitative PCR and transgenic assays. Conclusion Our findings indicate that JA pre-treatment could be a potential orchestrator of a broad-spectrum defense response that may help establish an ecologically friendly pest control strategy and offer a promising way of priming plants to induce defense responses againstA. alternata.