DIMBOA

DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one) is a naturally occurring hydroxamic acid, a benzoxazinoid. DIMBOA is a powerful antibiotic present in maize, wheat, rye, and related grasses,^[1]

DIMBOA

Names
Preferred IUPAC name 2,4-Dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one
Identifiers
CAS Number	15893-52-4 Y
3D model (JSmol)	Interactive image
ChemSpider	2268 N
PubChem CID	2358
UNII	TI783RU0DR Y
CompTox Dashboard (EPA)	DTXSID90936021
InChI InChI=1S/C9H9NO5/c1-14-5-2-3-6-7(4-5)15-9(12)8(11)10(6)13/h2-4,9,12-13H,1H3 N Key: GDNZNIJPBQATCZ-UHFFFAOYSA-N N
SMILES ON(C1=CC=C(OC)C=C1OC2O)C2=O
Properties
Chemical formula	C9H9NO5
Molar mass	211.173 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

DIMBOA was first identified in maize in 1962 as the "corn sweet substance".^[2] Etiolated maize seedlings have a very sweet, almost saccharin-like taste due to their high DIMBOA content.

The biosynthesis pathway from leading from maize primary metabolism to the production of DIMBOA has been fully identified.^[3][4] DIMBOA is stored as an inactive precursor, DIMBOA-glucoside, which is activated by glucosidases in response to insect feeding,^[1]

In maize, DIMBOA functions as natural defense against European corn borer (Ostrinia nubilalis) larvae,^[5][6] beet armyworms (Spodoptera exigua),^[7] corn leaf aphids (Rhopalosiphum maidis),^[8] other damaging insect pests, and pathogens, including fungi and bacteria.^[1][9][10] The exact level of DIMBOA varies between individual plants,^[11][12] but higher concentrations are typically found in young seedlings and the concentration decreases as the plant ages.^[13] Natural variation in the Bx1 gene influences the DIMBOA content of maize seedlings.^[11][14] In adult maize plants, the DIMBOA concentration is low, but it is induced rapidly in response to insect feeding.^[15] The methyltransferases Bx10, Bx11, and Bx12 convert DIMBOA into HDMBOA (2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one), which can be more toxic for insect herbivores.^[12][7]

In addition to serving as a direct defensive compound due to its toxicity, DIMBOA can also function as a signaling molecule, leading to the accumulation of callose in response to treatment with chitosan (a fungal elicitor) and aphid feeding.^[12][16]

DIMBOA can also form complexes with iron in the rhizosphere and thereby enhance maize iron supply.^[17]

Specialized insect pests such as the western corn rootworm (Diabrotica virgifera virgifera) can detect complexes between DIMBOA and iron and use these complexes for host identification and foraging.^[17]