The mustard oil bomb, formerly known as the glucosinolate–myrosinase complex, is a chemical defense system against

herbivory A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat n ...

found in members of the

Brassicaceae Brassicaceae () or (the older but equally valid) Cruciferae () is a medium-sized and economically important Family (biology), family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous pla ...

(cabbage) family. The mustard oil bomb requires the activation of a common plant secondary metabolite,

glucosinolate Glucosinolates are natural components of many pungent plants such as mustard, cabbage, and horseradish. The pungency of those plants is due to mustard oils produced from glucosinolates when the plant material is chewed, cut, or otherwise damaged. ...

, by an enzyme, myrosinase. The defense complex is typical among plant defenses against herbivory in that the two molecules are stored in different compartments in the leaves of plants until the leaf is torn by an herbivore. The glucosinolate has a β-glucose and a sulfated

oxime In organic chemistry, an oxime is an organic compound belonging to the imines, with the general Chemical formula, formula , where R is an organic Side chain, side-chain and R' may be hydrogen, forming an aldoxime, or another organic functional g ...

. The myrosinase removes the β-glucose to form mustard oils that are toxic to herbivores. The defense system was named a "bomb" by Matile, because it, like a real bomb, is waiting to detonate upon disturbance of the plant tissue.

Countermeasures

There are many examples of biochemical adaptations to the mustard oil bomb. One occurs in the diamondback moth, ''Plutella xylostella''. This worldwide crop pest feeds exclusively on members of the Brassicaceae and has developed a defense against the glucosinolate-myrosinase complex. The moth has an enzyme, a

sulfatase In biochemistry, sulfatases are a class of enzymes of the esterase class that catalyze the hydrolysis of sulfate esters into an Alcohol (chemistry), alcohol and a bisulfate: :\ce \quad \xrightarrow

text Text may refer to: Written word * Text (literary theory) In literary theory, a text is any object that can be "read", whether this object is a work of literature, a street sign, an arrangement of buildings on a city block, or styles of clothi ...

\quad \ce These may be found on a rang ...

, that it uses to desulfate the glucosinolate, meaning the myrosinase cannot locate and remove the β-glucose to form the mustard oils. Plant hosts contain a variety of glucosinolates; while all of them have the β-glucose and sulfated oxime. The diamondback moth, however, can apparently desulfate a wide range of natural glucosinolates - perhaps all.

References

{{DEFAULTSORT:Glucosinolate-myrosinase complex Glucosinolates Herbivory

Countermeasures

See also

References