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Bacillus subtilis and Enterobacter cloacae endophytes from healthy Theobroma cacao L. trees can systemically colonize seedlings and promote growth.
Leite, Hianna Almeida Câmara; Silva, Anderson Barbosa; Gomes, Fábio Pinto; Gramacho, Karina Peres; Faria, José Cláudio; de Souza, Jorge Teodoro; Loguercio, Leandro Lopes.
Afiliação
  • Leite HA; Departamento Ciências Biológicas (DCB), Universidade Estadual de Santa Cruz (UESC), Rod. BR 415, Km 16, Ilhéus, BA 45662-000, Brazil.
Appl Microbiol Biotechnol ; 97(6): 2639-51, 2013 Mar.
Article em En | MEDLINE | ID: mdl-23212670
Clonal genotypes resistant to fungal diseases are an important component of the cocoa production system in southeastern Bahia state (Brazil), so that technologies for faster production of stronger and healthier plantlets are highly desirable. In this study, the effects of inoculated bacterial endophytes isolated from healthy adult cacao plants on seedlings, and aspects related to inoculation methods, colonization patterns, and photosynthesis were investigated. Sequencing of 16S rRNA, hsp-60, and rpo-B genes placed the wild-type isolates within the species Enterobacter cloacae (isolates 341 and 344) and Bacillus subtilis (isolate 629). Spontaneous rifampicin-resistant (rif(R)) variants for 344 were also produced and tested. Endophytic application was either by immersion of surface sterilized seeds in bacterial suspensions or direct inoculation into soil, 20 days after planting non-inoculated seeds into pots. Results from in vitro recovery of inoculated isolates showed that the wild-type endophytes and rif(R) variants systemically colonized the entire cacao seedlings in 15-20 days, regardless of the inoculation method. Some endophytic treatments showed significant increases in seedlings' height, number of leaves, and dry matter. Inoculation methods affected the combined application of endophytes, which maintained the growth-promotion effects, but not in the same manner as in single applications. Interestingly, the 344-3.2 rif(R) variant showed improved performance in relation to both the wild type and another related variant. Photosynthetic rates and stomatal conductance increased significantly for some endophytic treatments, being partially associated with effects on growth and affected by the inoculation method. The results suggest that E. cloacae and B. subtilis endophytes from healthy adult plants (not transmitted by seeds) were able to promote vegetative growth on cacao seedlings. The development of products for large-scale use in seedlings/plantlets production systems was discussed.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Bacillus subtilis / Cacau / Enterobacter cloacae / Plântula / Endófitos País/Região como assunto: America do sul / Brasil Idioma: En Revista: Appl Microbiol Biotechnol Ano de publicação: 2013 Tipo de documento: Article País de afiliação: Brasil País de publicação: Alemanha

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Bacillus subtilis / Cacau / Enterobacter cloacae / Plântula / Endófitos País/Região como assunto: America do sul / Brasil Idioma: En Revista: Appl Microbiol Biotechnol Ano de publicação: 2013 Tipo de documento: Article País de afiliação: Brasil País de publicação: Alemanha