Species-Specific Glucosylation of DIMBOA in Larvae of the Rice Armyworm

Sasai, Hiroaki; Ishida, Masahiro; Murakami, Kenjiro; Tadokoro, N.; Ishihara, Atsushi; Nishida, Ritsuo; Mori, Naoki

doi:10.1271/bbb.80903

Cited by 45 publications

(39 citation statements)

References 28 publications

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“…In the related Asian corn borer [Ostrinia furnacalis (Guenée)], larvae can withstand low levels of hydroxamic acids, most likely by enzymatically degrading them (Kojima et al 2010). In contrast, the rice armyworm [Mythimna separata (Walker)] glycosylates benzoxazinoids making them less reactive (Sasai et al 2009). ECB may have similar detoxification strategies, or alternatively, defenses other than the ones studied here may be more important in stem resistance against ECB feeding in the stem (McMullen et al 2009).…”

Section: Discussionmentioning

confidence: 99%

Rapidly Induced Chemical Defenses in Maize Stems and Their Effects on Short-term Growth of Ostrinia nubilalis

et al. 2011

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Plants damaged by insect herbivory often respond by inducing a suite of defenses that can negatively affect an insect's growth and fecundity. Ostrinia nubilalis (European corn borer, ECB) is one of the most devastating insect pests of maize, and in the current study, we examined the early biochemical changes that occur in maize stems in response to ECB herbivory and how these rapidly induced defenses influence the growth of ECB. We measured the quantities of known maize defense compounds, benzoxazinoids and the kauralexin class of diterpenoid phytoalexins. ECB herbivory resulted in decreased levels of the benzoxazinoid, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one)-β-D-glucopyranose (DIMBOA-Glc), and a corresponding increase in 2-(2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one)-β-D-glucopyranose (HDMBOA-Glc). Total quantities of benzoxazinoids and kauralexins were increased as early as 24 h after the initiation of ECB feeding. The plant hormones, jasmonic acid (JA) and ethylene (ET), and the transcripts encoding their key biosynthetic enzymes also accumulated in response to ECB herbivory, consistent with a role in defense regulation. The combined pharmacological application of JA and the ET precursor, 1-aminocyclopropane-1-carboxylic acid to stem internode tissue likewise resulted in changes in benzoxazinoids similar to that observed with ECB damage. Despite the fact that maize actively mounts a defense response to ECB stem feeding, no differences in percent weight gain were observed between ECB larvae that fed upon non-wounded control tissues compared to tissues obtained from plants previously subjected to 24 h ECB stem herbivory. These rapid defense responses in maize stems do not appear to negatively impact ECB growth, thus suggesting that ECB have adapted to these induced biochemical changes.

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Section: Discussionmentioning

confidence: 99%

Rapidly Induced Chemical Defenses in Maize Stems and Their Effects on Short-term Growth of Ostrinia nubilalis

et al. 2011

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“…Our benzoxazinoid profiling experiments revealed no negative feedback effects of BX13 on other benzoxazinoids, which allows us to rule out metabolic trade-offs as an explanation for the absence of herbivore growth effects in the BX13 NILs. Many chewing herbivores seem to be able to circumvent benzoxazinoid toxicity by reglycosylating the aglucones (Sasai et al, 2009;Glauser et al, 2011;Maag et al, 2014;Wouters et al, 2014). Because of this mechanism, even the generalist Egyptian cotton leafworm is able to tolerate DIMBOA concentrations of 200 mg g 21 FW .…”

Section: Dim 2 Boa-glc and Hdm 2 Boa-glc Specifically Increase Plant mentioning

confidence: 99%

Biosynthesis of 8-O-methylated benzoxazinoid defense compounds in maize

et al. 2016

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Benzoxazinoids are important defense compounds in grasses. Here, we investigated the biosynthesis and biological roles of the 8-O-methylated benzoxazinoids, DIM 2 BOA-Glc and HDM 2 BOA-Glc. Using quantitative trait locus mapping and heterologous expression, we identified a 2-oxoglutarate-dependent dioxygenase (BX13) that catalyzes the conversion of DIMBOA-Glc into a new benzoxazinoid intermediate (TRIMBOA-Glc) by an uncommon reaction involving a hydroxylation and a likely ortho-rearrangement of a methoxy group. TRIMBOA-Glc is then converted to DIM 2 BOA-Glc by a previously described O-methyltransferase BX7. Furthermore, we identified an O-methyltransferase (BX14) that converts DIM 2 BOA-Glc to HDM 2 BOA-Glc. The role of these enzymes in vivo was demonstrated by characterizing recombinant inbred lines, including Oh43, which has a point mutation in the start codon of Bx13 and lacks both DIM 2 BOA-Glc and HDM 2 BOA-Glc, and Il14H, which has an inactive Bx14 allele and lacks HDM 2 BOA-Glc in leaves. Experiments with near-isogenic maize lines derived from crosses between B73 and Oh43 revealed that the absence of DIM 2 BOA-Glc and HDM 2 BOA-Glc does not alter the constitutive accumulation or deglucosylation of other benzoxazinoids. The growth of various chewing herbivores was not significantly affected by the absence of BX13-dependent metabolites, while aphid performance increased, suggesting that DIM 2 BOA-Glc and/or HDM 2 BOA-Glc provide specific protection against phloem feeding insects.

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“…However, both insect and vertebrate UGTs are known to be bound to the endoplasmic reticulum in a similar manner. Enzyme activities of the insect UGTs are detected in the fat body, midgut and other tissues (Ahmad and Hopkins, 1993b), and are directed towards a variety of plant allelochemicals (Ahmad and Hopkins, 1993a;Sasai et al, 2009). Interestingly, the enzymes were also detected in the antenna of D. melanogaster (Wang et al, 1999).…”

Section: Introductionmentioning

confidence: 99%