Page 32 - Volume 6, Issue 2, July 2013

© Benaki Phytopathological Institute
Bempelou et al. 80
half life of 20 days. In the same time period
the initial concentration of diazinon was de-
creased up to 88% of the control when Rh.
glutinis was added, and up to 94% in the
case of Rh. rubra. These results were in line
to our in vitro biodegradation study. It has to
be mentioned that the trials were conduct-
ed in harvested tomato fruits and therefore
are considered as a worst case scenario since
the reaction between the microorganism
and the insecticide was studied under con-
trolled conditions without the interferences
of other factors (biological, environmental)
which might contribute to the disappear-
ance of diazinon from the plant surfaces.
Conclusions
Our findings supported that the epiphytic
yeasts Rh. glutinis and Rh. rubra are capable of
biodegrading diazinon in liquid cultures and
on tomatoes at high rates. The involvement
of GSTs in the degradation was indicated by
our in vitro and in vivo studies. Therefore,
the use of these microorganisms might be a
promising method for the removal or detoxi-
fication of diazinon residues on tomatoes.
Literature cited
Abu- Qare, A.W. and Abou-Donia, M.B. 2001. Deter-
mination of diazinon, chlorpyrifos and their me-
tabolites in rat plasma and urine by high- per-
formance liquid chromatography. Journal of
Chromatographic Science , 39: 200- 204.
Abu- Qare, A.W. and Abou-Donia, M.B. 2001. High
Performance Liquid Chromatographic determi-
nation of diazinon, permethrin, DEET (N, N-di-
ethyl-m-toluamide) and their metabolites in rat
plasma and urine. Fresenious Journal of Analyti-
cal Chemistry, 370: 403- 407.
Adhaya, T.K., Sudhakar- Barik, Sethunan N. 1981. Hy-
drolysis of selected organophosphorous insec-
ticides by two bacteria flooded soil. Journal of
Applied Bacteriology, 50: 167-172.
Barik, S., Munnecke, D.M. 1982. Enzymatic hydrolysis
of concentrated diazinon in soil. Environmental
Contamination Toxicology , 29: 235-239.
Bartsch, E. 1974. Diazinon II. Residues in Plants, Soil
and Water. Residue Reviews, 51: 37-68, 5-59.
Bavcon, M., Trebse, P. and Zupzncic- Kralj 2003. In-
vestigations of the determination of trans-
formations of diazinon and malathion under
environmental conditions using gas chroma-
tography coupled with a flame ionization de-
tector. Chemosphere, 50: 595- 601.
Bilthoven 1996. Ministry of Public Health, Welfare
and Sport. The Netherlands. Analytical meth-
ods for pesticide residues in foodstuffs. Sixth
edition, P. Van Zoonen Ed.
Bolognesi, C. and Moraso, G. 2000. Genotoxicity of
pesticides: potential risk for consumers. Trends
in Food Science and Technology, 11: 182-187.
Bradford, M.M. 1976. A rapid and sensitive method
for the quantitation of microgramquantities of
protein utilizing the principle of protein-dye
binding. Analytical Biochemistry, 72: 248-54.
Cycon, M., Wojcik, M. and Piotrowska-Seget Z.
2009. Biodegradation of the organophospho-
rus insecticide diazinon by Serratia sp. and Pseu-
domonas sp. and their use in bioremediation of
contaminated soil. Chemosphere, 76: 494-501.
Domagalski, J.L. and Kuivila, K.M. 1993. Distribu-
Table 2 . Residues of diazinon (mg/kg) on tomato fruits sprayed with 2mg/kg diazinon and
10 6cells/mL of the yeasts Rhodotorula glutinis and Rhodotorula rubra. In control the fruits were
sprayed only with diazinon and in application the fruits were sprayed with diazinon and the
inoculum. Each value is the mean of three replicates ± relative standard deviation.
Days
Concentration of diazinon
C (mg/kg)
Rhodotorula glutinis Rhodotorula rubra
Control Application
%
of the
control
Control Application
%
of the
control
5 1.68 ± 1.23 1.37 ± 0.55 18.5 1.68 ± 2.04 1.13 ± 1.1 67.3
20 0.83 ± 0.89 0.1 ± 1.63 88 0.83 ± 0.45 Nda 94
a Not detected