title: Effects of systemic pesticides imidacloprid and metalaxyl on the phyllosphere of pepper plants.
abstract: Microbes inhabiting the phyllosphere of crops are exposed to pesticides applied either directly onto plant foliage or indirectly through soil. Although, phyllosphere microbiology has been rapidly evolving, little is still known regarding the impact of pesticides on the epiphytic microbial community and especially on fungi. We determined the impact of two systemic pesticides (metalaxyl and imidacloprid), applied either on foliage or through soil, on the epiphytic fungal and bacterial communities via DGGE and cloning. Both pesticides induced mild effects on the fungal and the bacterial communities. The only exception was the foliage application of imidacloprid which showed a more prominent effect on the fungal community. Cloning showed that the fungal community was dominated by putative plant pathogenic ascomycetes (Erysiphaceae and Cladosporium), while a few basidiomycetes were also present. The former ribotypes were not affected by pesticides application, while selected yeasts (Cryptococcus) were stimulated by the application of imidacloprid suggesting a potential role in its degradation. A less diverse bacterial community was identified in pepper plants. Metalaxyl stimulated an Enterobacteriaceae clone which is an indication of the involvement of members of this family in fungicide degradation. Further studies will focus on the isolation of epiphytic microbes which appear to be stimulated by pesticides application.
authors.affiliation: University of Thessaly, Department of Biochemistry and Biotechnology, Ploutonos 26 and Aiolou Street, 41221 Larisa, Greece.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Moulas
authors.forename: Christos
authors.initials: C
authors.lastname: Petsoulas
authors.forename: Konstantina
authors.initials: K
authors.lastname: Rousidou
authors.forename: Chiara
authors.initials: C
authors.lastname: Perruchon
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Karas
authors.forename: Dimitrios G
authors.initials: DG
authors.lastname: Karpouzas
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives / Q000494:pharmacology; D001203:Ascomycota / Q000187:drug effects* / Q000235:genetics; D002212:Capsicum / Q000187:drug effects / Q000382:microbiology*; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000235:genetics; D005658:Fungi / Q000187:drug effects / Q000235:genetics; D007093:Imidazoles / Q000494:pharmacology; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000494:pharmacology; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology
chemical_list: D007093:Imidazoles; D000073943:Neonicotinoids; D009574:Nitro Compounds; D012336:RNA, Ribosomal, 16S; C028175:metalaxyl; C082359:imidacloprid; D000409:Alanine