BURKHOLDERIA SP. SCMS54 INCREASES TOMATO
GROWTH IN THE PRESENCE OF CADMIUM
Dourado, MN1*; Martins, P F1; Quecine, MC 1; Piotto, FA 1; Souza, LA 1; Tezotto, T2; Gaziola, SA1; Azevedo, RA1.
Departamento de Genética, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba, SP. 2Departamento de
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Produção Vegetal, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba, SP.
*e-mail: [email protected]
Key-words: heavy metal, plant growth-promoting bacteria (PGPB), phytoremediation, tolerance mechanism
Cadmium is a heavy metal that is present in contaminated soils due the increased use of chemical fertilizers, pesticides and
industrial and/or domestic effluents. In soils, this metal affects microorganisms communities, but it can also be taken up by
plants leading to reduced growth/yield and eventually affect humans and animals by entering the food chain. Phytoremediation
techniques employ the use of plants to remove heavy metals from a contaminated environment (soil and water), with less impact
and at a lower cost. Furthermore, plant roots can interact with heavy metal-tolerant microorganisms, which may also promote
plant growth. Once the interaction involving plant-metal-microorganism-soil is understood, the phytoremediation process can be
applied. The present study evaluated the interaction of a heavy metal-multi tolerant bacterium isolated from a Cd-contaminated
soil (Burkholderia sp. SCMS54), with tomato plant (Solanum lycopersicum L. cv Calabash Rouge) in the presence of cadmium.
The tolerant bacterium was transformed with gfp fluorescence gene to monitor plant colonization. It was observed a preference
for root surface colonization by SCMS54:gfp. During this interaction with tomato plants exposed to Cd, the tolerant bacterium
lead to a decrease in plant peroxide concentration, decrease in chlorosis levels, promoted plant growth and reduced the root
Cd absorption, resulting in an increase in plant tolerance to this metal. The results showed that tomato plants inoculated with
Burkholderia sp. SCMS54 exhibited better growth than non-inoculated plants when in the presence of Cd, as a result of the
beneficial bacterial-plant root interaction.
Financial Support: FAPESP, CNPq and CAPES.
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