Lepidopteran herbivory and oral factors induce transcripts encoding novel terpene synthases in <i>Medicago truncatula</i>

Gomez, S. Karen; Cox, M.; Bede, Jacqueline C.; Inoue, Kentaro; Alborn, Hans T.; Tumlinson, James H.; Korth, Kenneth L.

doi:10.1002/arch.20037

Cited by 55 publications

(53 citation statements)

References 40 publications

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“…The 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase) is a rate-controlling enzyme catalyzing the conversion of HMG-CoA to mevalonate, one of the first steps in terpenoid biosynthesis. Other affected genes were TERPENE SYNTHASE1, coding for a sesquiterpene synthase (Gomez et al, 2005), and SQUALENE EPOXIDASE3, coding for an enzyme helping in the first oxygenation step in sterol biosynthesis (Chugh et al, 2003). b-Amyrin synthase is committed to the first step in the biosynthesis of saponins, which are glycosylated triterpenoids protecting plants against pathogens and pests (Morita et al, 2000;Suzuki et al, 2002;Thimmappa et al, 2014).…”

Section: Am Symbiosis Up-regulates Genes Involved In Terpenoid Biosynmentioning

confidence: 99%

Enhanced Secondary- and Hormone Metabolism in Leaves of Arbuscular Mycorrhizal Medicago truncatula

et al. 2017

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Arbuscular mycorrhizas (AM) are the most common symbiotic associations between a plant's root compartment and fungi. They provide nutritional benefit (mostly inorganic phosphate [P i ]), leading to improved growth, and nonnutritional benefits, including defense responses to environmental cues throughout the host plant, which, in return, delivers carbohydrates to the symbiont. However, how transcriptional and metabolic changes occurring in leaves of AM plants differ from those induced by P i fertilization is poorly understood. We investigated systemic changes in the leaves of mycorrhized Medicago truncatula in conditions with no improved P i status and compared them with those induced by high-P i treatment in nonmycorrhized plants. Microarray-based genome-wide profiling indicated up-regulation by mycorrhization of genes involved in flavonoid, terpenoid, jasmonic acid (JA), and abscisic acid (ABA) biosynthesis as well as enhanced expression of MYC2, the master regulator of JA-dependent responses. Accordingly, total anthocyanins and flavonoids increased, and most flavonoid species were enriched in AM leaves. Both the AM and P i treatments corepressed iron homeostasis genes, resulting in lower levels of available iron in leaves. In addition, higher levels of cytokinins were found in leaves of AM-and P i -treated plants, whereas the level of ABA was increased specifically in AM leaves. Foliar treatment of nonmycorrhized plants with either ABA or JA induced the up-regulation of MYC2, but only JA also induced the up-regulation of flavonoid and terpenoid biosynthetic genes. Based on these results, we propose that mycorrhization and P i fertilization share cytokinin-mediated improved shoot growth, whereas enhanced ABA biosynthesis and JA-regulated flavonoid and terpenoid biosynthesis in leaves are specific to mycorrhization.

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Section: Am Symbiosis Up-regulates Genes Involved In Terpenoid Biosynmentioning

confidence: 99%

Enhanced Secondary- and Hormone Metabolism in Leaves of Arbuscular Mycorrhizal Medicago truncatula

et al. 2017

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“…Over a dozen nematode and insect R genes have been either cloned or mapped in close association with NBS-LRR gene clusters, yet no corresponding ligands have been identified (Rossi et al, 1998;Brotman et al, 2002;Klingler et al, 2005;Williamson and Kumar, 2006). In legumes, insect elicitors and potential ligands also include 3-hydroxypropanoate esters of long-chain a,v-diols, termed bruchins, present in pea (Pisum sativum) weevil oviposition fluid and the fatty acid amino acid conjugates (FACs) from lepidopteran OS (Doss et al, 2000;Gomez et al, 2005). On pea pods, fmol amounts of bruchins induce rapid tumorlike neoplastic cellular growths and isoflavone phytoalexins that act to inhibit weevil larvae establishment (Doss et al, 2000;Cooper et al, 2005).…”

Section: E1mentioning

confidence: 99%

“…In, and Vu-GE1 In), while corresponding root-derived OS peptides were undetectable (,10 fmol mL depolarization of membrane potentials, respectively (Maffei et al, 2004;Gomez et al, 2005). Support for FAC receptors comes from kinetic investigations of plasma membrane binding in maize (Zea mays); however, these proteins remain unidentified .…”

Section: E1mentioning

confidence: 99%

Cowpea Chloroplastic ATP Synthase Is the Source of Multiple Plant Defense Elicitors during Insect Herbivory

et al. 2007

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In cowpea (Vigna unguiculata), fall armyworm (Spodoptera frugiperda) herbivory and oral secretions (OS) elicit phytohormone production and volatile emission due to inceptin [Vu-In; 1 ICDINGVCVDA 2 ], a peptide derived from chloroplastic ATP synthase g-subunit (cATPC) proteins. Elicitor-induced plant volatiles can function as attractants for natural enemies of insect herbivores. We hypothesized that inceptins are gut proteolysis products and that larval OS should contain a mixture of related peptides. In this study, we identified three additional cATPC fragments, namely Vu- In, and Vu-GE1 In, respectively; however, Vu-In 2A proved inactive. Shortly following ingestion of recombinant proteins harboring cATPC sequences, larval OS revealed similar concentrations of the three elicitors with 80% of the potential inceptin-related peptides recovered. Rapidly shifting peptide ratios over time were consistent with continued proteolysis and preferential stability of inceptin. Likewise, larvae ingesting host plants with inceptin precursors containing an internal trypsin cleavage site rapidly lost OS-based elicitor activity. OS containing inceptin elicited a rapid and sequential induction of defense-related phytohormones jasmonic acid, E, and salicylic acid at 30, 120, and 240 min, respectively, and also the volatile (E)-4,8-dimethyl-1,3,7-nonatriene. Similar to established peptide signals such as systemin and flg22, amino acid substitutions of Vu-In demonstrate an essential role for aspartic acid residues and an unaltered C terminus. In cowpea, insect gut proteolysis following herbivory generates inappropriate fragments of an essential metabolic enzyme enabling plant non-self-recognition.

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“…These enzymes convert GGDP more efficiently than FDP in vitro and their transcript levels correlate with the formation of TMTT (SlGLS) and hydroxylinalool glycosides (NaGLS). Two geranyllinallool synthases from Fabaceae, PlTPS2 from P. lunatus (Brillada et al, 2013) and MtTPS3 from Medicago truncatula (Gomez et al, 2005;Arimura et al, 2008), belong to a separate clade of terpene synthases possibly involved in volatile terpene production. These enzymes are expressed in the plastid and convert GDP and FDP with higher in vitro efficiencies than GGDP.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Biosynthetic Pathways for the Production of the Volatile Homoterpenes DMNT and TMTT in Zea mays

et al. 2016

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Plant volatiles not only have multiple defense functions against herbivores, fungi, and bacteria, but also have been implicated in signaling within the plant and toward other organisms. Elucidating the function of individual plant volatiles will require more knowledge of their biosynthesis and regulation in response to external stimuli. By exploiting the variation of herbivoreinduced volatiles among 26 maize (Zea mays) inbred lines, we conducted a nested association mapping and genome-wide association study (GWAS) to identify a set of quantitative trait loci (QTLs) for investigating the pathways of volatile terpene production. The most significant identified QTL affects the emission of (E)-nerolidol, linalool, and the two homoterpenes (E)-3,8-dimethyl-1,4,7-nonatriene (DMNT) and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT). GWAS associated a single nucleotide polymorphism in the promoter of the gene encoding the terpene synthase TPS2 with this QTL. Biochemical characterization of TPS2 verified that this plastid-localized enzyme forms linalool, (E)-nerolidol, and (E,E)-geranyllinalool. The subsequent conversion of (E)-nerolidol into DMNT maps to a P450 monooxygenase, CYP92C5, which is capable of converting nerolidol into DMNT by oxidative degradation. A QTL influencing TMTT accumulation corresponds to a similar monooxygenase, CYP92C6, which is specific for the conversion of (E,E)-geranyllinalool to TMTT. The DMNT biosynthetic pathway and both monooxygenases are distinct from those previously characterized for DMNT and TMTT synthesis in Arabidopsis thaliana, suggesting independent evolution of these enzymatic activities.

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Lepidopteran herbivory and oral factors induce transcripts encoding novel terpene synthases in Medicago truncatula

Cited by 55 publications

References 40 publications

Enhanced Secondary- and Hormone Metabolism in Leaves of Arbuscular Mycorrhizal Medicago truncatula

Enhanced Secondary- and Hormone Metabolism in Leaves of Arbuscular Mycorrhizal Medicago truncatula

Cowpea Chloroplastic ATP Synthase Is the Source of Multiple Plant Defense Elicitors during Insect Herbivory

Characterization of Biosynthetic Pathways for the Production of the Volatile Homoterpenes DMNT and TMTT in Zea mays

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