Q_o inhibitors (Q_oI), or quinone outside inhibitors, are a group of

fungicide Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their spores. A fungistatic inhibits their growth. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality, ...

s used in

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...

. Some of these fungicides are among the most popular in the world. Q_oI are chemical compounds which act at the quinol ''outer'' binding site of the cytochrome ''bc''₁ complex. Most QI common names end in -strobin and so are often called strobs. Q_oI's are the resulting fusion of three fungicides families, the well-known family of

strobilurin Strobilurins are a group of natural products and their synthetic analogs. A number of strobilurins are used in agriculture as fungicides. They are part of the larger group of QIs (Quinone outside Inhibitors), which act to inhibit the respiratory c ...

s and two new families, represented by

fenamidone Fenamidone is a foliar fungicide used on grapes, ornamentals, potatoes, tobacco Tobacco is the common name of several plants in the genus '' Nicotiana'' of the family Solanaceae, and the general term for any product prepared from the ...

and

famoxadone Famoxadone is a fungicide to protect agricultural products against various fungal diseases on fruiting vegetables, tomatoes, potatoes, curcurbits, lettuce and grapes.

. Some strobilurins are

azoxystrobin Azoxystrobin is the ISO common name for an organic compound that is used as a fungicide. It is a broad spectrum systemic active ingredient widely used in agriculture to protect crops from fungal diseases. It was first marketed in 1996 using the b ...

, kresoxim-methyl, picoxystrobin,

pyraclostrobin Pyraclostrobin is a quinone outside inhibitor ( QI)-type fungicide used in agriculture. Among the QIs, it lies within the strobilurin chemical class. Use Pyraclostrobin is used to protect ''Fragaria'', ''Rubus idaeus'', ''Vaccinium corymbosum'', ...

, and trifloxystrobin.

Usage

QoI fungicides are used on a wide range of crops, such as cereals, vines, pome fruits, cucurbits, tomatoes and potatoes. For example, they are used as fungicides for cereals, against ''Erysiphe graminis'' f.sp ''tritici'' responsible for the powdery

mildew Mildew is a form of fungus. It is distinguished from its closely related counterpart, mould, largely by its colour: moulds appear in shades of black, blue, red, and green, whereas mildew is white. It appears as a thin, superficial growth consi ...

wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...

or against ''

Septoria tritici ''Zymoseptoria tritici'', synonyms ''Septoria tritici'', ''Mycosphaerella graminicola'', is a species of filamentous fungus, an ascomycete in the family ''Mycosphaerellaceae''. It is a wheat plant pathogen causing septoria leaf blotch that is ...

'', responsible for septoria leaf spot in wheat. They are also commonly used for

vine A vine (Latin ''vīnea'' "grapevine", "vineyard", from ''vīnum'' "wine") is any plant with a growth habit of trailing or scandent (that is, climbing) stems, lianas or runners. The word ''vine'' can also refer to such stems or runners themselv ...

culture, against ''

Plasmopara viticola ''Plasmopara viticola'', the causal agent of grapevine downy mildew, is a heterothallic oomycete that overwinters as oospores in leaf litter and soil. In the spring, oospores germinate to produce macrosporangia, which under wet condition release ...

'', responsible for

downy mildew Downy mildew refers to any of several types of oomycete microbes that are obligate parasites of plants. Downy mildews exclusively belong to the Peronosporaceae family. In commercial agriculture, they are a particular problem for growers of crucif ...

or in oïdium treatment.

List

* QIs: :* methoxy-acrylates: ::*

::* coumoxystrobin ::* enoxastrobin ::* flufenoxystrobin ::* picoxystrobin ::* pyraoxystrobin :* methoxy-acetamides: ::* mandestrobin :* methoxy-carbamates: ::*

::* pyrametostrobin ::* triclopyricarb :* oximino-acetates: ::* kresoxim-methyl ::* trifloxystrobin :* oximino-acetamides: ::* dimoxystrobin ::* fenaminstrobin ::* metominostrobin ::* orysastrobin :* oxazolidine-diones: ::*

famoxadone Famoxadone is a fungicide to protect agricultural products against various fungal diseases on fruiting vegetables, tomatoes, potatoes, curcurbits, lettuce and grapes.

:* dihydro-dioxazines: ::* fluoxastrobin :* imidazolinones: ::*

:* benzyl-carbamates: ::* pyribencarb * QI subgroup A: :* tetrazolinones: ::* metyltetraprole

Resistance

Main group resistance

Almost all these fungicides are in the same

cross-resistance Cross-resistance is when something develops resistance to several substances that have a similar mechanism of action. For example, if a certain type of bacteria develops resistance to one antibiotic, that bacteria will also have resistance to sev ...

group ( FRAC 11) and must be managed carefully to avoid the appearance of

fungicide resistance Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their spores. A fungistatic inhibits their growth. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality, ...

. All group 11s are cross-resistant with each other. Some fungicide resistance has been observed in many crop pathogens (such as in the case of wheat powdery

), Resistance to group 11 is conferred by

cytochrome b Cytochrome b within both molecular and cell biology, is a protein found in the mitochondria of eukaryotic cells. It functions as part of the electron transport chain and is the main subunit of transmembrane cytochrome bc1 and b6f complexes. F ...

mutations

G143A Cytochrome b within both molecular and cell biology, is a protein found in the mitochondria of eukaryotic cells. It functions as part of the electron transport chain and is the main subunit of transmembrane cytochrome bc1 and b6f complexes. F ...

and

F129L Cytochrome b within both molecular and cell biology, is a protein found in the mitochondria of eukaryotic cells. It functions as part of the electron transport chain and is the main subunit of transmembrane cytochrome bc1 and b6f complexes. F ...

, and by other mechanisms.

Tetrazolinone resistance

The tetrazolinones consist of only one molecule, metyltetraprole. This constitutes FRAC 11A. 11A is not cross-resistant with 11 resistance conferred by

References

{{reflist, refs= {{cite web , title=quinone outside inhibitor (CHEBI:141153) , website=The

European Bioinformatics Institute The European Bioinformatics Institute (EMBL-EBI) is an Intergovernmental Organization (IGO) which, as part of the European Molecular Biology Laboratory (EMBL) family, focuses on research and services in bioinformatics. It is located on the Well ...

< EMBL-EBI , url=http://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:141153 , access-date=2021-02-20

External links

Fungicides Resistance Action Committee, QoI
Includes information on QoI

working group A working group, or working party, is a group of experts working together to achieve specified goals. The groups are domain-specific and focus on discussion or activity around a specific subject area. The term can sometimes refer to an interdis ...

activities.
Gray Leaf Spot Resistance to Strobulurins
Fungicides Quinone outside inhibitors