Citrus phenylpropanoids and defense against pathogens . Part I : Metabolic 1 profiling in elicited fruits 2 3

19 Penicillium spp. are among the major postharvest pathogens of citrus fruit. 20 Induction of natural resistance in fruits constitutes one of the alternatives to 21 chemical fungicides. Here, we investigated the involvement of the 22 phenylpropanoid pathway in the induction of resistance in Navelate oranges by 23 examining changes in the metabolic profile of upon eliciting citrus fruits. By 24 using both HPLC-PDA-FD and HPLC-PDA-QTOF-MS allowed the identification 25 of several compounds that seem to be relevant for induced resistance. In 26 elicited fruits, a greater diversity of phenolic compounds was observed in the 27 flavedo (outer colored part of the peel) as compared to the albedo (inner white 28 part). Moreover, only small changes were detected in the most abundant citrus 29 flavonoids. The coumarin scoparone was among the compounds with the 30 highest induction upon elicitation. Two other highly induced compounds were 31 identified as citrusnin A and drupanin aldehyde. All three compounds are known 32 to exert antimicrobial activity. Our results suggest that phenylpropanoids and 33 their derivatives play an important role in the induction of resistance in citrus 34 fruit. 35 36