Isolamento, identificação e inoculação de bactérias produtoras de auxinas associadas às raízes de orquídeas
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Data
2009-06-26
Autores
Galdiano Júnior, Renato Fernandes [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A rizosfera favorece a colonização radicular por rizobactérias promotoras do crescimento de plantas (RPCPs), as quais podem oferecer importantes benefícios para a hospedeira. Este estudo teve o objetivo de isolar e identificar bactérias produtoras de auxinas das espécies Cattleya walkeriana, Cyrtopodium paludicolum, Ionopsis utricularioides, Oeceoclades maculata, Phalaenopsis amabilis e Vanilla planifolia e avaliar a inoculação de sementes e plântulas da orquídea brasileira Cattleya walkeriana. Ao total, foram isolados 85 bactérias, 67 delas produtoras de auxinas (quantificados por ensaios colorimétrico e detectados por CLAE) e 26 foram identificadas pelo sequenciamento parcial do gene 16S rRNA. Seis isolados produtores de auxinas foram inoculados em bioensaios. Para a inoculação in vitro, sementes foram inoculadas com os isolados Burkholderia RzW32, Enterobacter Endw37, Curtobacterium Endw57, Bacilllus EndW60 e testemunha representada por água destilada autoclavada em meio nutritivo Knudson-C e mantidas em câmara de incubação com luminosidade e temperatura controladas. Após 120 dias, a germinação do tratamento controle apresentou-se bem desenvolvida, ao contrário de sementes dos tratamentos inoculados. No experimento de bacterização ex vitro, plântulas germinadas em cultivo assimbiótico in vitro foram inoculadas com os isolados Burkholderia RzW32, Curtobacterium RzW35, Enterobacter EndW37, Bacillus EndW48 e testemunha. Após 90 dias de cultivo em condições de casa de vegetação, foram avaliados porcentagem de sobrevivência, área foliar, número de raízes, comprimento das raízes, massa de matéria seca da parte radicular e da parte aérea, índice de aumento da área foliar e índice de aumento da massa seca total. Curtobacterium sp. e Burkholderia sp. proporcionaram a menor eficiência para o crescimento enquanto...
The rhizosphere promotes root colonization by Plant growthpromoting rizobacteria (PGPR), which may offer significant benefits to the host . This study aimed to isolate and identify auxin-producing bacteria of the species Cattleya walkeriana, Cyrtopodium paludicolum, Ionopsis utricularioides, Oeceoclades maculata, Phalaenopsis amabilis and Vanilla planifolia, and evaluate seeds and seedlings innoculation of the Brazilian orchid Cattleya walkeriana. In total, 85 bacteria were isolated, 67 of them produce auxins (quantified by colorimetric assays and detected by HPLC) and 26 were identified by partial sequencing of 16S rRNA gene. Six-producing isolates were inoculated in auxin bioassays. For in vitro inoculation, seeds were inoculated with isolates Burkholderia RzW32, Enterobacter Endw37, Curtobacterium Endw57, Bacilllus EndW60 and control represented by distilled autoclaved water in nutrient medium Knudson-C and kept in an incubation chamber with controlled temperature and luminosity. After 120 days, the germination of the control treatment presented was well developed, unlike seeds of inoculated treatments. In the experiment of bacterization ex vitro, asymbiotic in vitro germinated seedlings were inoculated with isolates Burkholderia RzW32, Curtobacterium RzW35, Enterobacter EndW37, Bacillus EndW48 and control. After 90 days of cultivation in a greenhouse, were evaluated for survival percentage, leaf area, number of roots, root length, dry matter of the root and shoot, rate of increase in leaf area index and increase in total dry mass. Curtobacterium sp. RzW35 and Burkholderia sp. RzW32 provided the lowest efficiency for growth while Bacillus sp. EndW48 and Enterobacter sp. EndW37 to encourage growth in all parameters investigated and may be recommended for growth and survival during ex vitro acclimatization of seedlings of Cattleya walkeriana.
The rhizosphere promotes root colonization by Plant growthpromoting rizobacteria (PGPR), which may offer significant benefits to the host . This study aimed to isolate and identify auxin-producing bacteria of the species Cattleya walkeriana, Cyrtopodium paludicolum, Ionopsis utricularioides, Oeceoclades maculata, Phalaenopsis amabilis and Vanilla planifolia, and evaluate seeds and seedlings innoculation of the Brazilian orchid Cattleya walkeriana. In total, 85 bacteria were isolated, 67 of them produce auxins (quantified by colorimetric assays and detected by HPLC) and 26 were identified by partial sequencing of 16S rRNA gene. Six-producing isolates were inoculated in auxin bioassays. For in vitro inoculation, seeds were inoculated with isolates Burkholderia RzW32, Enterobacter Endw37, Curtobacterium Endw57, Bacilllus EndW60 and control represented by distilled autoclaved water in nutrient medium Knudson-C and kept in an incubation chamber with controlled temperature and luminosity. After 120 days, the germination of the control treatment presented was well developed, unlike seeds of inoculated treatments. In the experiment of bacterization ex vitro, asymbiotic in vitro germinated seedlings were inoculated with isolates Burkholderia RzW32, Curtobacterium RzW35, Enterobacter EndW37, Bacillus EndW48 and control. After 90 days of cultivation in a greenhouse, were evaluated for survival percentage, leaf area, number of roots, root length, dry matter of the root and shoot, rate of increase in leaf area index and increase in total dry mass. Curtobacterium sp. RzW35 and Burkholderia sp. RzW32 provided the lowest efficiency for growth while Bacillus sp. EndW48 and Enterobacter sp. EndW37 to encourage growth in all parameters investigated and may be recommended for growth and survival during ex vitro acclimatization of seedlings of Cattleya walkeriana.
Descrição
Palavras-chave
Plant growth-promiting, Rhizobacteria, Indolacetic acid (IAA), Orchids, Orquídea, Rizobactérias, Ácido indolacético (AIA)
Como citar
GALDIANO JÚNIOR, Renato Fernandes. Isolamento, identificação e inoculação de bactérias produtoras de auxinas associadas às raízes de orquídeas. 2009. xiii, 67 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2009.