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Selection of bioantagonistic bacteria to be used in biological control of Rhizoctonia solani in tomato Jaime R. Montealegre* Rodrigo Reyes Luz
María Pérez Rodrigo Herrera Polyana Silva Ximena Besoain *Corresponding Author
Bacteria from the rhizoplane
and
surrounding soil of healthy and Rhizoctonia solani diseased tomato plants,
cropped in greenhouse of the V Region of Chile, were collected. The best bacterial
strains, based on their ability to control development of three R.
solani isolates (identified as belonging to the anastomosis groups AG-2-1,
AG‑4), were identified as B. subtilis (one isolate) and B.
lentimorbus (two different isolates). All bacterial isolates resulted effective
for the in vitro control of growth of all R. solani isolates, where
the control mechanisms used by the bacteria do not involve the secretion of fungal
cell wall hydrolytic enzymes. R. solani AG-2-1 was more
sensitive than R. solani AG-4. On the other hand, all bacteria grew well
in conditions similar to those that can be found at the field level (considering
pH, salinity, Fe3+ and temperature) and showed a good capacity of
tomato root colonization. These results suggest that the B.
subtilis and B. lentimorbus isolates studied have an excellent potential
to be used as biocontrol agents of R. solani in tomato greenhouses at
the field level. |
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