Mitotic crossing-over induced by two commercial herbicides in diploid strains of the fungus Aspergillus nidulans

Abstract

ABSTRACT. Some herbicides are suspected of promoting teratogenic, carcinogenic and mutagenic events. Detection of induced mitotic crossing-over has proven to be an indirect way of testing the carcinogenic properties of suspicious substances, because mitotic crossing-over is involved in the multistep process of carcinogenesis. We examined mitotic crossing-over induced by two commercial herbicides (diuron and trifluralin) in diploid strains of Aspergillus nidulans based on the homozygotization index. Low doses (2.5 μg/mL) of diuron were sufficient to increase the mean homozygotization index in 2.1 and 11.3 times for UT448// UT196 and Dp II-I//UT196, respectively, whereas the same dose of trifluralin increased this mean only 1.2 (UT448//UT196) and 3.5 (Dp II-I// UT196) times, respectively. The lower homozygotization index value found for trifluralin could be due to its interference with mitotic crossingover in eukaryotic cells. We concluded that the diploid Dp II-I//UT196 of A. nidulans is more sensitive to organic compounds than UT448//UT196; these compounds cause recombinational events at a greater frequency in the latter diploid. This system holds promise as an initial test for carcinogenicity of organic compounds, including herbicides.

Antifungal Activity of Endophytic Actinomyetes against Fusarium Wilt (Fusarium oxysporum) of Banana Trees (Musa acuminata)

“…These compounds have often been related as one of the most important tools to control the soilborne diseases with low environmental impact and toxic effect for humans and animals, well-desired traits for new consumer's requirements (Cardoso et al, 2010).…”

Gene homozygosis and mitotic recombination induced by camptothecin and irinotecan in Aspergillus nidulans diploid cells

“…Heterozygous diploid strains of the filamentous fungus Aspergillus nidulans have been used to evaluate the recombinogenic potential of several chemical compounds (Domingues Zucchi et al 2005, Cardoso et al 2010, Santos et al 2012. A. nidulans is considered a model system for the mitotic crossing-over study because its cells spend the greater part of their cycle in the G2 phase.…”

Biological control of phytopathogenic fungi by endophytic actinomycetes isolated from maize (Zea mays L.)

“…This awareness relies mainly in the noxious effects of the pesticides on the environmental and human health (Cardoso et al 2010). Several efforts have been made to find less hazardous options for controlling these plant pathogens among which the biological control using the microorganisms has been demonstrated to be a feasible alternative (Zucchi et al 2008) but it is not widely used on commercial scale (Bressan 2003;Medeiros et al 2012).…”

“…In fact, antibiotics produced by the filamentous bacteria, mainly Streptomyces spp., have been reported to be able to inhibit the development of a broad range of phytopathogenic fungi and/or bacteria (Berg et al 2001). Also, these compounds have often been related as one of the most important tools to control the soil-borne diseases (Buchenauer 1998) with low environmental impact and toxic effect for humans and animals, well-desired traits for new consumer's requirements (Cardoso et al 2010). One of these important soil-borne diseases is the root rot caused by Pythium aphanidermatum.…”