Functional Interactions in the Use of Direct and Indirect Defences in Native
            <i>Nicotiana</i>
            Plants

Baldwin, Ian T.

doi:10.1002/9780470515679.ch6

Cited by 6 publications

(4 citation statements)

References 58 publications

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“…In other systems, both serine and cysteine PIs have been identified as main digestive proteases. For example, Nicotiana attenuata plants attacked by herbivore such as Manduca sexta accumulate trypsin PIs (Zavala et al, 2004), the neurotoxin nicotine (Baldwin, 1999), and various secondary metabolites comprising oxylipins (Wu et al, 2008; see Howe and Jander, 2008; Wu and Baldwin, 2010, for reviews). Serine proteases have been detected in many insect orders, including Lepidoptera , Diptera , Orthoptera , Hymenoptera , and Coleoptera (Christeller et al, 1992).…”

Section: Discussionmentioning

confidence: 99%

An Ethylene-Protected Achilles’ Heel of Etiolated Seedlings for Arthropod Deterrence

et al. 2016

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A small family of Kunitz protease inhibitors exists in Arabidopsis thaliana, a member of which (encoded by At1g72290) accomplishes highly specific roles during plant development. Arabidopsis Kunitz-protease inhibitor 1 (Kunitz-PI;1), as we dubbed this protein here, is operative as cysteine PI. Activity measurements revealed that despite the presence of the conserved Kunitz-motif the bacterially expressed Kunitz-PI;1 was unable to inhibit serine proteases such as trypsin and chymotrypsin, but very efficiently inhibited the cysteine protease RESPONSIVE TO DESICCATION 21. Western blotting and cytolocalization studies using mono-specific antibodies recalled Kunitz-PI;1 protein expression in flowers, young siliques and etiolated seedlings. In dark-grown seedlings, maximum Kunitz-PI;1 promoter activity was detected in the apical hook region and apical parts of the hypocotyls. Immunolocalization confirmed Kunitz-PI;1 expression in these organs and tissues. No transmitting tract (NTT) and HECATE 1 (HEC1), two transcription factors previously implicated in the formation of the female reproductive tract in flowers of Arabidopsis, were identified to regulate Kunitz-PI;1 expression in the dark and during greening, with NTT acting negatively and HEC1 acting positively. Laboratory feeding experiments with isopod crustaceans such as Porcellio scaber (woodlouse) and Armadillidium vulgare (pillbug) pinpointed the apical hook as ethylene-protected Achilles’ heel of etiolated seedlings. Because exogenous application of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) and mechanical stress (wounding) strongly up-regulated HEC1-dependent Kunitz-PI;1 gene expression, our results identify a new circuit controlling herbivore deterrence of etiolated plants in which Kunitz-PI;1 is involved.

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Section: Discussionmentioning

confidence: 99%

An Ethylene-Protected Achilles’ Heel of Etiolated Seedlings for Arthropod Deterrence

et al. 2016

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“…The quinolinic acid is catalyzed by quinolinic acid phosphate ribosyltransferase (QPRT) to form the nicotinamide adenine dinucleotide (NAD), which is further cycled through the pyridine nucleotide pathway to nicotinic acid [7,8]. The biosynthesis of nicotine can be induced by herbivore feeding, insect biting, and pathogen attacking [9], as well as jasmonic acid and its derivatives (JAs), mechanical wounding and topping [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

The Nicotiana tabacum Mediator subunit MED25 regulates nicotine biosynthesis through interacting with the basic helix-loop-helix (bHLH) transcription factor NtMYC2s

Bai

Yang

et al. 2021

Preprint

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Nicotine is one of the most important secondary metabolites in tobacco, and its biosynthesis can be induced by topping and jasmonic acid treatment. NtMYC2s play pivotal roles in the regulation of nicotine. The mediator server as a bridge betwen the transcription factors and RNA polymerase in order to facilitates transcription and functions in plants. However, the role of mediator in the regulation of nicotine biosynthesis remains unknown. In this study, we firstly identify the NtMED25 through homologous analysis. NtMED25 interacts with NtMYC2s through the MD region. Interestingly, the nicotine content is decreased in the the knock-down transgenic lines of NtMED25, and the expression levels of two nicotine biosynthesis genes, NtQPT2 and NtPMT2, are also reduced when compared with that in the wild-type plants. Furthermore, NtMED25 enhances the binding of NtMYC2a/ NtMYC2b to the promoter of NtPMT2 and NtQPT2, and then facilitates the nicotine biosynthesis. Therefore, our study revealed the function of mediator in the regulation of nicotine, and provide the insight role on the transcriptional regulation of plant secondary metabolites.

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“…Accumulation of a wide range of defense compounds has been reported, and the key elements of JA signaling were identified [10,13]. Insect feeding provokes overlapping as well as distinct defenses that include local and systemic reactions and additionally lead to the attraction of the insects’ enemies through the emission of green leaf volatiles comprising Z -3-hexenal and the corresponding C6-volatile alcohol [( Z )-3-hexenol], thus, providing an indirect defense involving interplant communication [14,15,16,17,18,19,20,21,22,23,24].…”

Section: Introductionmentioning

confidence: 99%

ALLENE OXIDE SYNTHASE and HYDROPEROXIDE LYASE, Two Non-Canonical Cytochrome P450s in Arabidopsis thaliana and Their Different Roles in Plant Defense

Rustgi

Springer

Kang

et al. 2019

IJMS

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The channeling of metabolites is an essential step of metabolic regulation in all living organisms. Multifunctional enzymes with defined domains for metabolite compartmentalization are rare, but in many cases, larger assemblies forming multimeric protein complexes operate in defined metabolic shunts. In Arabidopsis thaliana, a multimeric complex was discovered that contains a 13-lipoxygenase and allene oxide synthase (AOS) as well as allene oxide cyclase. All three plant enzymes are localized in chloroplasts, contributing to the biosynthesis of jasmonic acid (JA). JA and its derivatives act as ubiquitous plant defense regulators in responses to both biotic and abiotic stresses. AOS belongs to the superfamily of cytochrome P450 enzymes and is named CYP74A. Another CYP450 in chloroplasts, hydroperoxide lyase (HPL, CYP74B), competes with AOS for the common substrate. The products of the HPL reaction are green leaf volatiles that are involved in the deterrence of insect pests. Both enzymes represent non-canonical CYP450 family members, as they do not depend on O2 and NADPH-dependent CYP450 reductase activities. AOS and HPL activities are crucial for plants to respond to different biotic foes. In this mini-review, we aim to summarize how plants make use of the LOX2–AOS–AOC2 complex in chloroplasts to boost JA biosynthesis over volatile production and how this situation may change in plant communities during mass ingestion by insect pests.

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Functional Interactions in the Use of Direct and Indirect Defences in Native Nicotiana Plants

Cited by 6 publications

References 58 publications

An Ethylene-Protected Achilles’ Heel of Etiolated Seedlings for Arthropod Deterrence

An Ethylene-Protected Achilles’ Heel of Etiolated Seedlings for Arthropod Deterrence

The Nicotiana tabacum Mediator subunit MED25 regulates nicotine biosynthesis through interacting with the basic helix-loop-helix (bHLH) transcription factor NtMYC2s

ALLENE OXIDE SYNTHASE and HYDROPEROXIDE LYASE, Two Non-Canonical Cytochrome P450s in Arabidopsis thaliana and Their Different Roles in Plant Defense

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