Preliminary study on the microbiota associated with Cimiciato hazelnuts

Cimiciato hazelnuts are inedible and unmarketable. This defect is caused by the feeding activity of variousspecies of pentatomids. The cimiciato-defect in hazelnuts is characterized by the presence of dry and necrotictissues on the kernel, alterations in the lipid composition profile, and an increased susceptibility to lipid oxidation.These factors affect the organoleptic parameters and shelf-life of the product. Insect biting into hazelnutsdetermines the release of enzymes associated to saliva that induce biotic responses in plant tissues andmetabolism alterations in kernels. Moreover, microbial inoculation during the feeding process is a well-documentedphenomenon, as in the case of Eremothecium coryli (Peglion) Kurtzman, the causal agent of kerneldry rot in hazelnuts. Our study aims to explore the microbiota associated with the cimiciato defect occurringin insect-bitten hazelnuts of the San Giovanni cultivar harvested in Teano (CE), Campania region. Fruits wereexternally sterilised, shelled and disinfected. Cimiciato and healthy hazelnuts were then placed onto potatodextrose agar (PDA) or PDA + 1% lactic acid and transferred to a growth chamber. Fungal and bacterial colonieswere observed and counted, to assess their presence or absence in each tested fruit. Noteworthy, cimiciatohazelnuts showed a higher presence of fungi compared to healthy hazelnuts. In contrast to this, no significantdifferences were found for bacteria. Further studies will be required for the molecular and phenotypic characterizationof cimiciato-associated microbes together with metabolomic analysis, to determine how they contributeto development of this defect.