In this article the topic of DIMBOA will be addressed from different perspectives and approaches. DIMBOA is an issue of great relevance today, it raises debate and controversy in various areas, and its study is crucial to understanding the complexity of contemporary society. Throughout these pages, the multiple edges that make up DIMBOA will be analyzed, their practical and theoretical implications will be examined, and different reflections will be offered that invite critical reflection. From different disciplines and fields of knowledge, DIMBOA will be examined in a rigorous and detailed manner, with the purpose of providing new perspectives and enriching the debate around this phenomenon.
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 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]
References
^ abcNiemeyer HM (1988). "Hydroxamic acids (4-hydroxy-1,4-benzoxazin-3-ones), defence chemicals in the gramineae". Phytochemistry. 27 (11): 3349–3358. doi:10.1016/0031-9422(88)80731-3.
^Hamilton RH, Bandurski RS, Reusch WH (1962). "Isolation and characterization of a cyclic hydroxamate from Zea mays". Cereal Chemistry. 39: 107–113.
^Klun JA, Guthrie WD, Hallauer AR, Russell WA (1970). "Genetic Nature of the Concentration of 2,4-dihydroxy-7-methoxy 2H-l,4-benzoxazin- 3(4H)-one and Resistance to the European Corn Borer in a Diallel Set of Eleven Maize Inbreds1". Crop Science. 10 (1): 87–90. doi:10.2135/cropsci1970.0011183X001000010032x.
^Cambier V, Hance T, de Hoffmann E (January 2000). "Variation of DIMBOA and related compounds content in relation to the age and plant organ in maize". Phytochemistry. 53 (2): 223–9. doi:10.1016/S0031-9422(99)00498-7. PMID10680175.