PT.03.50 STRESS TOLERANCE OF THE ENTOMOPATHOGENIC

12º SICONBIOL, Simpósio de Controle Biológico - 18 a 21 de julho de 2011
“Mudanças climáticas e sustentabilidade: quebra de paradigmas”
PT.03.50
STRESS TOLERANCE OF THE ENTOMOPATHOGENIC FUNGUS TOLYPOCLADIUM SPP.
Santos MP1; Dias LP1; Ferreira PC1; Rangel DEN1 - 1Universidade do Vale do Paraíba - Instituto de
Pesquisa e Desenvolvimento
Studies on the stress resistance of insect-pathogenic fungi are very important to better understand the
survival of these organisms in the environment. Therefore, this study examined the cold activity (8 ± 1 °C
for seven days), UV-B tolerance (weighted UV-B irradiance at 870.44 mW m-2 for 1, 2, 3 and 4 h) and
wet-heat tolerance (45° C for 1, 2, 3 and 4 h) of two isolates of Tolypocladium cylindrosporum (ARSEF
3392 and 5558), one isolate of T. geodes (ARSEF 3275), and two isolates of T. Inflatum (ARSEF 4772
and 4877) based on their germination, compared with a Metarhizium robertsii isolate. After 3 h of UV-B
exposure, the two isolates of T. cylindrosporum were more resistant than the other Tolypocladium isolates
but were similar to the M. robertsii isolate. All Tolypocladium isolates, however, were less tolerant to
UV-B radiation than the isolate of M. robertsii after 4 h of UV exposure. The isolates of T. inflatum and
T. geodes, which had similar heat tolerance, were the least heat tolerant compared with the isolates of T.
cylindrosporum and M. robertsii. After 4 h of heat exposure, the germination of T. inflatum and T. geodes
was approximately 10%. The heat tolerance of the T. cylindrosporum isolates was similar to the M.
robertsii isolate. For cold activity, both T. cylindrosporum isolates germinated to ca. 100% in only three
days, both T. inflatum isolates germinated approximately 50% after three days. T. geodes germinated
approximately 30% after five days and on the sixth day it germinated approximately 80%. The M.
robertsii isolate did not germinate after seven days. The isolates of T. cylindrosporum, therefore, were the
most heat and UV-B tolerant as well as had the highest cold activity as compared with the other species.
The tolerance of M. robertsii to UV-B radiation and heat was similar to the tolerance of T.
cylindrosporum. We sincerely thank the National Council for Scientific and Technological Development
(CNPq) of Brazil for grant support # 473104/2008-3
Palavras-chaves: Tolypocladium, entomopathogenic fungi, UV-B radiation, heat, germination, cold
activity.
257