Enhancing Fruit\nResistance against Fungal Pathogens\nUsing a Pathogen-Associated Molecular Pattern PdEIX

Fruit is an essential part of the human diet, and postharvest\nfungal\ndiseases are the major cause of fruit postharvest losses worldwide.\nPathogen-associated molecular patterns (PAMPs) are important elicitors\nfrom microbes, and the recognition between microbial PAMPs and plant\nreceptors leads to PAMP-triggered immunity. Here, we identified a\nPAMP, PdEIX, that is an important protein elicitor with plant immunity-inducing\nactivity, from the citrus green mold pathogen Penicillium\ndigitatum. PdEIX showed an apoplastic location similar\nto that of known PAMPs, and plant receptor-like protein NbEIX2, receptor-like\nkinase BAK1, and other signaling components of plant immunity were\nrequired for PdEIX-triggered plant cell death in the model plant Nicotiana benthamiana. Moreover, PdEIX triggered\na series of immune responses in citrus fruit and enhanced the resistance\nof citrus and other fruit against fungal pathogens. Our results indicate\nthat application of a microbial PAMP as the plant immunity inducer\nis an effective strategy for controlling postharvest fungal diseases\nof fruit.