Cytological evaluation of the effect of azoxystrobin and alternative oxidase inhibitors in Botrytis cinerea

Abstract

Azoxystrobin (AZ), a strobilurin-derived fungicide, is known to inhibit mitochondrial respiration in fungi by blocking the electron transport chain in the inner mitochondrial membrane. Germination was strongly inhibited when Botrytis cinerea spore suspension was treated with AZ and the alternative oxidase (AOX) inhibitors, salicylhydroxamic acid (SHAM) and n-propyl gallate. However, chemical death indicators trypan blue and propidium iodide showed that those spores were still alive. When the spore suspension in the AZ and SHAM solution was replaced with distilled water, the germination rate almost recovered, at least during the first 2 days of incubation with AZ and SHAM solution. No morphological alteration was detected in the cells treated with AZ and SHAM, especially in mitochondria, using transmission electron microscopy. Therefore, simultaneous application of AZ and AOX inhibitors has a fungistatic, rather than a fungicidal, action.

Genetic and Functional Investigation of Zn2Cys6Transcription Factors RSE2 and RSE3 in Podospora anserina

“…In plants, the alternative oxidase is present in some tissues or developmental stages and may also be induced in response to a variety of stresses (7)(8)(9). In most fungi, it is undetectable, or present at very low levels, under normal growth conditions but becomes expressed when the cytochrome respiratory chain is restricted by inhibitors such as antimycin, azoxystrobin, and cyanide or by mutations (10)(11)(12)(13). Under these conditions, the AOX bypasses respiratory complexes III and IV.…”

Design, Synthesis and Antifungal Activities of Novel Strobilurin Derivatives Containing Pyrimidine Moieties

“…To make a judgment on the antifungal potency of the strobilurin derivatives, the commercial fungicide, azoxystrobin was used as a positive control. 33 The antifungal results of all the compounds against Colletotrichum orbiculare, Botrytis cinerea Pers and Phytophthora capsici Leonian were listed in Table 1.…”

Sensitivity of <i>Leptosphaeria maculans</i> to pyraclostrobin in Alberta, Canada

“…Some fungal pathogens have been observed to exhibit in vitro resistance to QoIs through an alternative (Inoue et al 2012). The compound salicylhydroxamic acid (SHAM) blocks alternative respiration; therefore, it is important to include SHAM in sensitivity studies to avoid inaccurate interpretations of resistance (Wise et al 2008).…”

“…Specifically, they act on the Qo site located on the cytochrome bc1 enzyme complex (complex III) of the mitochondria (Gisi et al 2002). By interrupting the activity in the electron transport chain, QoI fungicides deprive the fungus of energy by preventing the formation of adenosine triphosphate (ATP) (Gisi et al 2002) and cause a build-up of electrons in the mitochondria (Inoue et al 2012). The overabundance of electrons results in the formation of reactive oxygen species (ROS) that damage the mitochondria and contribute to the death of the fungus (Inoue et al 2012).…”

“…By interrupting the activity in the electron transport chain, QoI fungicides deprive the fungus of energy by preventing the formation of adenosine triphosphate (ATP) (Gisi et al 2002) and cause a build-up of electrons in the mitochondria (Inoue et al 2012). The overabundance of electrons results in the formation of reactive oxygen species (ROS) that damage the mitochondria and contribute to the death of the fungus (Inoue et al 2012). Strobilurin fungicides, such as pyraclostrobin, have protectant and translaminar activity, and are very effective at inhibiting spore germination, which is an energy demanding stage in the fungal lifecycle (Bartlett et al 2002).…”