title: Cultivable bacteria isolated from apple trees cultivated under different crop systems: Diversity and antagonistic activity against Colletotrichum gloeosporioides.
abstract: This study evaluated the diversity of cultivable plant growth-promoting (PGP) bacteria associated with apple trees cultivated under different crop management systems and their antagonistic ability against Colletotrichum gloeosporioides. Samples of roots and rhizospheric soil from apple trees cultivated in organic and conventional orchards in southern Brazil were collected, together with soil samples from an area never used for agriculture (native field). Bacteria were identified at the genus level by PCR-RFLP and partial sequencing of the 16S rRNA, and were evaluated for some PGP abilities. The most abundant bacterial genera identified were Enterobacter (27.7%), Pseudomonas (18.7%), Burkholderia (13.7%), and Rahnella (12.3%). Sixty-nine isolates presented some antagonist activity against C. gloeosporioides. In a greenhouse experiment, five days after exposure to C. gloeosporioides, an average of 30% of the leaf area of plants inoculated with isolate 89 (identified as Burkholderia sp.) were infected, whereas 60 to 73% of the leaf area of untreated plants was affected by fungal attack. Our results allowed us to infer how anthropogenic activity is affecting the bacterial communities in soil associated with apple tree crop systems, and to obtain an isolate that was able to delay the emergence of an important disease for this culture.
authors.affiliation: Departamento de Genética , Instituto de Biociências , Universidade Federal do Rio Grande do Sul , Porto Alegre, RS , Brazil . ; Empresa de Pesquisa e Extensão Agropecuária de Santa Catarina , Lages, SC , Brazil .
authors.forename: João Frederico M
authors.initials: JF
authors.lastname: Dos Passos
authors.affiliation: Departamento de Genética , Instituto de Biociências , Universidade Federal do Rio Grande do Sul , Porto Alegre, RS , Brazil .
authors.forename: Pedro B
authors.initials: PB
authors.lastname: da Costa
authors.affiliation: Empresa de Pesquisa e Extensão Agropecuária de Santa Catarina , Lages, SC , Brazil .
authors.forename: Murilo D
authors.initials: MD
authors.lastname: Costa
authors.affiliation: Empresa de Pesquisa e Extensão Agropecuária de Santa Catarina , Lages, SC , Brazil .
authors.forename: Gilmar R
authors.initials: GR
authors.lastname: Zaffari
authors.affiliation: Empresa de Pesquisa e Extensão Agropecuária de Santa Catarina , Lages, SC , Brazil .
authors.forename: Gilberto
authors.initials: G
authors.lastname: Nava
authors.affiliation: Empresa de Pesquisa e Extensão Agropecuária de Santa Catarina , Lages, SC , Brazil .
authors.forename: José Itamar
authors.initials: JI
authors.lastname: Boneti
authors.affiliation: Fundação Estadual de Pesquisa Agropecuária , Porto Alegre, RS , Brazil .
authors.forename: Andréia Mara R
authors.initials: AM
authors.lastname: de Oliveira
authors.affiliation: Departamento de Genética , Instituto de Biociências , Universidade Federal do Rio Grande do Sul , Porto Alegre, RS , Brazil .
authors.forename: Luciane M P
authors.initials: LM
authors.lastname: Passaglia
keywords: Colletotrichum gloeosporioides; antagonistic activity; apple tree; plant growth-promoting bacteria