Occurrence and Characterization of 2-Hydroxy-1,4-benzoxazin-3-one and Indole Hydroxylases in Juvenile Wheat.
نویسندگان
چکیده
Cyclic hydroxamic acids, 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA) and its 7-methoxy analogue (DIMBOA), occur transiently in high amounts in wheat and maize during the juvenile, non-autotrophic stage of growth. To elucidate the biosynthetic enzymes operating for the transient production of these compounds, we examined the hydroxylating activities for 2-hydroxy-1,4-benzoxazin-3-one (HBOA), the immediate precursor of DIBOA, and indole, the first intermediate of the biosynthetic pathway that branches off from the tryptophan pathway, by using microsomes prepared from wheat seedlings. Both hydroxylases occurred soon after germination, reached a maximum 48 h after germination, and decreased to finally disappear as the plants grew into the autotrophic growth stage. The mode of appearance and disappearance similar to that of hydroxamic acids, suggesting that elevated expression of the whole set of enzymes involved in the biosynthesis after indole was responsible for the transient occurrence of hydroxamic acids. The hydroxylating activity was also observed for 1,4-benzoxazin-3-one, a putative precursor of HBOA, but to significantly less extent than that for HBOA and indole.
منابع مشابه
Species-specific glucosylation of DIMBOA in larvae of the rice Armyworm.
DIMBOA [2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one] is a benzoxazinoid (Bx), part of the chemical defense system of graminaceous plants such as maize, wheat, and rye. When Bombyx mori larvae were fed artificial diets containing DIMBOA, they died in three days. In contrast, Mythimna separata larvae, a serious pest of rice, maize, sorghum, wheat etc., grew well on the same diets. Three k...
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A gas-liquid chromatographic (GLC) procedure is reported for the quantitation of the trimethylsilyl (TMS) derivatives of substituted 2-hydroxy-2H-1,4-benzoxazin-3(4H)-ones (2-hydroxy-2H-1,4-benzoxazin-3(4H)-one[HBOA]; 2-hydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one[HMBOA];2,4- dihydroxy-2H-1,4-benzoxazin-3(4H)-one[DIBOA]; 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one[DIMBOA]; and 2,4-dihy...
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Localization of benzoxazinones that occur constitutively in wheat seedlings.
Occurrence and localization of novel antimicrobial and antifeeding compounds in wheat, 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA) and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), and their glucosides, were examined by staining wheat plants (Triticum aestivum L.) in the juvenile stage of growth by ferric chloride. The methanol extracts of the stained plant tissues gave a characteristic...
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ورودعنوان ژورنال:
- Bioscience, biotechnology, and biochemistry
دوره 63 9 شماره
صفحات -
تاریخ انتشار 1999