摘要：Citrus limon (L.) Burm. F. is an important evergreen fruit crop whose rhizosphere and phyllosphere microbiota have been characterized, while seed microbiota is still unknown. Bacterial and fungal endophytes were isolated from
C. limon surface-sterilized seeds. The isolated fungi—belonging to
Aspergillus,
Quambalaria and
Bjerkandera genera—and bacteria—belonging to
Staphylococcus genus—were characterized for indoleacetic acid production and phosphate solubilization. Next Generation Sequencing based approaches were then used to characterize the endophytic bacterial and fungal microbiota structures of surface-sterilized
C. limon seeds and of shoots obtained under aseptic conditions from in vitro growing seedlings regenerated from surface-sterilized seeds. This analysis highlighted that
Cutibacterium and
Acinetobacter were the most abundant bacterial genera in both seeds and shoots, while
Cladosporium and
Debaryomyces were the most abundant fungal genera in seeds and shoots, respectively. The localization of bacterial endophytes in seed and shoot tissues was revealed by Fluorescence In Situ Hybridization coupled with Confocal Laser Scanning Microscopy revealing vascular bundle colonization. Thus, these results highlighted for the first time the structures of endophytic microbiota of
C. limon seeds and the transmission to shoots, corroborating the idea of a vertical transmission of plant microbiota and suggesting its crucial role in seed germination and plant development.
