Resumo

SOLER ARANGO, Juliana; GILCHRIST RAMELLI, Elizabeth  e  PEREZ NARANJO, Juan Carlos. Evaluation of microorganisms with potential for plant growth promotion and biological control of Spongospora subterranea. Rev. colomb. biotecnol [online]. 2012, vol.14, n.1, pp.157-170. ISSN 0123-3475.

The powdery scab of potato is caused by the pathogen Spongospora subterranea which reduces the quality and yield of tubers and facilitates the establishment of other pathogens. This disease affects main potato production zones in the world, because there is not a completely effective and available control method against the disease, and due to the trading of infested seed tubers. Some research suggests that biological control agents could reduce the activity of S. subterranea through effects on the viability of their cystosoris or zoospores or by stimulating plant growth. In this research, bacteria previously isolated, from inside the roots, the rhizosphere and tuber peel of potato plants (Solanum tuberosum var. Diacol Capiro), were used, and then selected according to their capacity for producing total indoles and chitinases. Here was tested in parallel studies the capacity of nine bacterial isolates differing in total indole and chitinase production, for its capacity at increasing tuber sprout length and in promoting plant growth and biocontrol of S. subterranea . Inoculated in excised minitubers in laboratory most indole producing isolates tested resulted in increased tuber sprout length. In the greenhouse assay, in non-sterile soil and under a high pathogen pressure, two of the ten isolates selected because for their ability to produce total indoles and chitinases, showed plant growth promotion and possible biocontrol of the pathogen. These results suggest a great potential for the selection of biocontrol microorganisms and the development of new bioproducts from local microbial resources.

Palavras-chave : powdery scab of potato; total indole; chitinases; biological control; PGPR.

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