caa a22 4500 469042478 CHVBK 20180323132815.0 cr unu---uuuuu 170328e19920901xx s 000 0 eng 10.1007/BF01974389 doi (NATIONALLICENCE)springer-10.1007/BF01974389 Characterisation of energy-dependent efflux of imazalil and fenarimol in isolates of Penicillium italicum with a low, medium and high degree of resistance to DMI-fungicides [Elektronische Daten] [J. Guan, J. Kapteyn, A. Kerkenaar, M. De Waard] Differential accumulation of [14C]imazalil and [14C]fenarimol by germlings of wild-type and DMI-resistant isolates ofPenicillium italicum was studied at various pH values. At pH 7 and 8 the low-resistant isolate E300−3 accumulated 22% and 35%, respectively, less imazalil than the wild-type isolate W5. Imazalil accumulation at pH 5 and 6 was similar. Isolate E300−3 also accumulated less fenarimol as compared with the wild-type isolate. This difference was much more obvious than for imazalil and was observed at all pH values tested. Differences in accumulation of both imazalil and fenarimol between low (E300−3), medium (H17) and high resistant (I33) isolates were not observed. These results suggest that decreased accumulation of DMIs is responsible for a low level of resistance only and that additional mechanisms of resistance might operate in isolates with a medium and high degree of resistance. With all isolates fenarimol accumulation was energy-dependent. This was not obvious for imazalil. The wild-type and DMI-resistant isolates had a similar plasma membrane potential as determined with the probe [14C]tetraphenylphosphonium bromide ([14C]TPP+). Various test compounds, among which ATPase inhibitors, ionophoric antibiotics and calmodulin antagonists, affected the accumulation of [14C]TPP+, [14C]imazalil and [14C]fenarimol. No obvious correlation between the effects of the test compounds on accumulation levels of the fungicides and [14C]TPP+ could be observed. These results indicate that the plasma membrane potential does not mediate the efflux of DMI fungicides byP. italicum. Koninklijke Nederlandse Planteziektenkundige Vereniging, 1992 ATPase inhibitors nationallicence calmodulin antagonists nationallicence fenarimol nationallicence imazalil nationallicence ionophoric antibiotics nationallicence sterol 14α-demethylation inhibitors nationallicence tetraphenylphosphonium bromide nationallicence Guan J. Department of Phytopathology, Wageningen Agricultural University, P.O. Box 8025, 6700 EE, Wageningen, the Netherlands aut Kapteyn J. Department of Phytopathology, Wageningen Agricultural University, P.O. Box 8025, 6700 EE, Wageningen, the Netherlands aut Kerkenaar A. Denka International B.V., Hanzeweg 1, 3771 NG, Barneveld, the Netherlands aut De Waard M. Department of Phytopathology, Wageningen Agricultural University, P.O. Box 8025, 6700 EE, Wageningen, the Netherlands aut Netherlands Journal of Plant Pathology Kluwer Academic Publishers 98/5(1992-09-01), 313-324 0028-2944 98:5<313 1992 98 10658 https://doi.org/10.1007/BF01974389 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01974389 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Guan J. Department of Phytopathology, Wageningen Agricultural University, P.O. Box 8025, 6700 EE, Wageningen, the Netherlands aut NATIONALLICENCE 700 1- Kapteyn J. Department of Phytopathology, Wageningen Agricultural University, P.O. Box 8025, 6700 EE, Wageningen, the Netherlands aut NATIONALLICENCE 700 1- Kerkenaar A. Denka International B.V., Hanzeweg 1, 3771 NG, Barneveld, the Netherlands aut NATIONALLICENCE 700 1- De Waard M. Department of Phytopathology, Wageningen Agricultural University, P.O. Box 8025, 6700 EE, Wageningen, the Netherlands aut NATIONALLICENCE 773 0- Netherlands Journal of Plant Pathology Kluwer Academic Publishers 98/5(1992-09-01), 313-324 0028-2944 98:5<313 1992 98 10658 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer