Plant-Herbivore Interactions

Winter cress ( Barbarea vulgaris ) is resistant to a range of insect species. Some B. vulgaris genotypes are resistant, whereas others are susceptible, to herbivory by flea beetle larvae ( Phyllotreta nemorum ). Metabolites involved in resistance to herbivory by flea beetles were identified using ...

Genetic analysis of interspecific populations derived from crosses between the wild tomato species Solanum habrochaites f. sp. glabratum , which synthesizes and accumulates insecticidal methylketones (MK), mostly 2-undecanone and 2-tridecanone, in glandular trichomes, and cultivated tomato ( ...

Bemisia tabaci (whitefly) infestations and the subsequent transfer of viruses are the cause of severe losses in crop production and horticultural practice. To improve biological control of B. tabaci , we investigated repellent properties of plant-produced semiochemicals. The mix of headspace ...

Neotyphodium uncinatum and Neotyphodium siegelii are fungal symbionts (endophytes) of meadow fescue (MF; Lolium pratense ), which they protect from insects by producing loline alkaloids. High levels of lolines are produced following insect damage or mock herbivory (clipping). Although loline ...

The plant hormones salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) play crucial roles in the signaling network that regulates induced defense responses against biotic stresses. Antagonism between SA and JA operates as a mechanism to fine-tune defenses that are activated in response to ...

Treating wounds in Nicotiana attenuata leaves with Manduca sexta oral secretions (W+OS) mimics most changes elicited by M. sexta herbivory, but an unbiased analysis of the effect of the different OS constituents on volatile emissions is lacking. We used two-dimensional gas ...

Systemic signaling was investigated in both a dicot ( Vicia faba ) and a monocot ( Hordeum vulgare ) plant. Stimuli were applied to one leaf (S-leaf), and apoplastic responses were monitored on a distant leaf (target; T-leaf) with microelectrodes positioned in substomatal cavities of open stomata. ...

One of the first indirect defenses was identified in maize fed upon by larvae of the lepidopteran Egyptian cotton leaf worm, S . littoralis . The volatiles released in response to S . littoralis attack attract the parasitic braconid wasp Cotesia marginiventris (Hymenoptera), which oviposits ...

The diversification of chemical production in glandular trichomes is important in the development of resistance against pathogens and pests in two species of tomato. We have used genetic and genomic approaches to uncover some of the biochemical and molecular mechanisms that underlie the divergence ...

Magnaporthe oryzae is a hemibiotrophic fungal pathogen that causes rice ( Oryza sativa ) blast. Although M. oryzae as a whole infects a wide variety of monocotyledonous hosts, no dicotyledonous plant has been reported as a host. We found that two rice pathogenic strains of M. oryzae , KJ201 and ...

Glucosinolates are a group of thioglucosides that are components of an activated chemical defense found in the Brassicales. Plant tissue damage results in hydrolysis of glucosinolates by endogenous thioglucosidases known as myrosinases. Spontaneous rearrangement of the aglucone yields reactive ...

Glucosinolates are secondary metabolites found almost exclusively in the order Brassicales. They are synthesized from a variety of amino acids and can have numerous side chain modifications that control biological function. We investigated the biosynthesis of 2-hydroxybut-3-enyl glucosinolate, ...

Acyl sugars containing branched-chain fatty acids (BCFAs) are exuded by glandular trichomes of many species in Solanaceae, having an important defensive role against insects. From isotope-feeding studies, two modes of BCFA elongation have been proposed: (1) fatty acid synthase-mediated two-carbon ...

In this study, transcriptomics and metabolomics data were integrated in order to examine the regulation of glucosinolate (GS) biosynthesis in Arabidopsis ( Arabidopsis thaliana ) and its interface with pathways of primary metabolism. Our genetic material for analyses were transgenic plants ...

We previously cloned and characterized a novel jacalin-like lectin gene from wheat ( Triticum aestivum ) plants that responds to infestation by Hessian fly ( Mayetiola destructor ) larvae, a major dipteran pest of this crop. The infested resistant plants accumulated higher levels of Hfr-1 (for ...

Our aim in this Update article is to briefly review these recent findings that have added fresh insights into our understanding of how JA signals are transmitted within the cell. Our particular focus will be on the roles of a recently discovered class of repressors whose destruction through a ...

Plants are in constant interaction with other organisms. These interactions can be benign, beneficial, or detrimental for a plant. Plants need to not only distinguish between these interactions but also must have the ability to respond in a timely manner to an opportunistic invasion. This may ...

Glucosinolates are the inert storage form of a two-part phytochemical defense system in which the enzyme myrosinase generates an unstable intermediate that rapidly rearranges into the biologically active product. This rearrangement step generates simple nitriles, epithionitriles, or ...

Priming also occurs in woody plants. Frost et al. (2007) showed that leaves of hybrid poplar saplings ( Populus deltoides x nigra ) can be primed both by exposure to HIPVs and through internal wound signaling following gypsy moth larvae ( Lymantria dispar ) feeding. A follow-up study (C.J. Frost, ...

Caeliferins are recently identified HAMPs composed of saturated and monounsaturated sulfated α -hydroxy fatty acids with 15 to 20 carbons where the ω -carbon is functionalized with either a sulfated hydroxyl or a carboxyl conjugated via an amide bond to Gly ( Fig. 2 ; Alborn et al., 2007 ). ...

Plants can be attacked by arthropods both above and below ground. The ensuing systemic defense response of the plant can affect even the most distant tissues. Both primary and secondary metabolic profiles of shoots can be altered upon root herbivory and vice versa ( Gange and Brown, 1989 ; Bezemer ...

Root herbivores are among the most harmful insects attacking crop plants (e.g. corn root worm, Diabrotica spp.), and the handful of species known to attack roots of the major crop plants dominate the literature on belowground resistance ( Blossey and Hunt-Joshi, 2003 ). Although specific ...

Disrupting gene function by the use of RNAi is a well-established technique in insect genetics based on delivery by injection into insect cells or tissues. The observation that RNAi could also be effective in reducing gene expression, measured by mRNA level, when fed to insects ( Turner et al., ...

Phytophages breach the integrity of plant tissues to recover nutrients from foliage, seeds, pollen, nectar, roots, or shoots. While many herbivores cause extensive damage, phloem-feeding insects, such as aphids and whiteflies, cause modest to barely perceptible damage, respectively. Phloem-feeding ...

Mitogen-activated protein (MAP) kinases transfer information from sensors to cellular responses in all eukaryotes. It is therefore not surprising that several MAP kinases have been implicated in plant defense signaling ( Menke et al., 2004 ; Nakagami et al., 2005 ). Petersen et al. (2000) ...

We thank Mary Schuler for serving as our patient mentor in molecular methodology and Anurag Agrawal, Kevin Wanner, Evan DeLucia, and three anonymous reviewers for helpful comments on this manuscript. Since the genome sequence was published in 2000, Arabidopsis has proved to be an outstanding model ...

A major challenge for current biology is to integrate research approaches that address different levels of biological organization, from subcellular mechanisms to functions in ecological communities. The study of plant-insect interactions provides interesting options for this. Ample information at ...

Whether a given secondary metabolite plays a role in herbivore protection is best determined by planting isogenic plants that both do and do not produce the metabolite into the plants' native environment where they can be confronted with native herbivore communities. With the development of ...

Jasmonates (JAs) comprise a class of related oxylipin signaling molecules that have overlapping roles in regulating both stress responses and development in plants. Stress responses that depend on JA signaling include not only defense against insects but also defense against microbial pathogens, as ...

It is now clear that the jasmonate (JA) family of lipid-derived signals plays a prominent and conserved role in promoting plant resistance to herbivores. Browse and Howe (2008) discuss these roles, as well as recent progress in elucidating the mechanism of JA signaling. One notable recent ...

Plants have to cope with various abiotic and biotic impacts as a consequence of changing environments, which can impair their ability to sexually reproduce. The main objective of this study was to investigate whether green leaf herbivory, having one of the most hazardous biotic impacts, would have ...

The brown planthopper ( Nilaparvata lugens Stål; BPH) is a specialist herbivore on rice ( Oryza sativa ) that ingests phloem sap from the plant through its stylet mouthparts. Electronic penetration graphs revealed that BPH insects spent more time wandering over plants carrying the resistance genes ...

Jasmonate (JA) and its amino acid conjugate, jasmonoyl-isoleucine (JA-Ile), play important roles in regulating plant defense responses to insect herbivores. Recent studies indicate that JA-Ile promotes the degradation of JASMONATE ZIM-domain (JAZ) transcriptional repressors through the activity of ...

Plants damaged by insects can synthesize and release volatile chemicals that attract natural enemies of the herbivore. The maize ( Zea mays subsp. mays ) terpene synthase gene stc1 is part of that indirect defense response, being induced in seedling blades in response to herbivory by beet army ...

Genetic variation within and among populations provides the raw material for evolution. Although many studies describe inter- and intraspecific variation of defensive metabolites, little is known about variation among plant populations within early signaling responses elicited by herbivory or by ...

Like many crucifer-specialist herbivores, Pieris rapae uses the presence of glucosinolates as a signal for oviposition and larval feeding. Arabidopsis thaliana glucosinolate-related mutants provide a unique resource for studying the in vivo role of these compounds in affecting P. rapae oviposition. ...

Plant cystatins, similar to other defense proteins, include hypervariable, positively selected amino acid sites presumably impacting their biological activity. Using 29 single mutants of the eighth domain of tomato ( Solanum lycopersicum ) multicystatin, Sl CYS8, we assessed here the potential of ...

To achieve a thorough understanding of plant-aphid interactions, it is necessary to investigate in detail both the plant and insect side of the interaction. The pea aphid (PA; Acyrthosiphon pisum ) has been selected by an international consortium as the model species for genetics and genomics ...

Continuous mechanical damage initiates the rhythmic emission of volatiles in lima bean ( Phaseolus lunatus ) leaves; the emission resembles that induced by herbivore damage. The effect of diurnal versus nocturnal damage on the initiation of plant defense responses was investigated using MecWorm, a ...

Whereas jasmonic acid (JA) and its amino acid conjugates, particularly JA-isoleucine (Ile), are known to play important roles in plant-herbivore interactions, whether other compounds also function as signals independently of JA-Ile and whether conjugates elicit systemic responses are unknown. To ...

The Venus flytrap ( Dionaea muscipula ) possesses an active trapping mechanism to capture insects with one of the most rapid movements in the plant kingdom, as described by Darwin. This article presents a detailed experimental investigation of trap closure by mechanical and electrical stimuli and ...

In this study, we introduce the Micro-Electrode Ion Flux Estimation technique as a sensitive and accurate technique to study systemin-induced changes in ion fluxes from isolated nearly intact plant tissues. Our results demonstrate the effectiveness and value of the Micro-Electrode Ion Flux ...

We investigated the functional and biochemical variability of Kunitz trypsin inhibitor (KTI) genes of Populus trichocarpa × Populus deltoides . Phylogenetic analysis, expressed sequence tag databases, and western-blot analysis confirmed that these genes belong to a large and diverse gene family ...

In bioassays with artificial diets, the 17-hydroxygeranyllinalool diterpenoid glycosides (HGL-DTGs) of Nicotiana attenuata function as antifeedants for the plant's adapted herbivore, tobacco hornworm ( Manduca sexta ). To determine whether HGL-DTGs have a defensive function in planta, we suppressed ...

Sebacina vermifera , a growth-promoting endophytic fungus, significantly increases Nicotiana attenuata 's growth but impairs both its herbivore resistance and its accumulation of the costly, jasmonic acid (JA)-regulated defense protein, trypsin proteinase inhibitor (TPI). To determine if the ...

In cowpea ( Vigna unguiculata ), fall armyworm ( Spodoptera frugiperda ) herbivory and oral secretions (OS) elicit phytohormone production and volatile emission due to inceptin [ Vu -In; + ICDINGVCVDA − ], a peptide derived from chloroplastic ATP synthase γ -subunit (cATPC) proteins. ...

The tomato ( Solanum lycopersicum ) Mi - 1 gene encodes a protein with putative coiled-coil nucleotide-binding site and leucine-rich repeat motifs. Mi - 1 confers resistance to root-knot nematodes ( Meloidogyne spp.), potato aphids ( Macrosiphum euphorbiae ), and sweet potato whitefly ( Bemisia ...

Plant defense against insect herbivores is mediated in part by enzymes that impair digestive processes in the insect gut. Little is known about the evolutionary origins of these enzymes, their distribution in the plant kingdom, or the mechanisms by which they act in the protease-rich environment of ...

The basal defenses important in curtailing the development of the phloem-feeding silverleaf whitefly ( Bemisia tabaci type B; SLWF) on Arabidopsis ( Arabidopsis thaliana ) were investigated. Sentinel defense gene RNAs were monitored in SLWF-infested and control plants. Salicylic acid ...

Phloem-feeding pests cause extensive crop damage throughout the world, yet little is understood about how plants perceive and defend themselves from these threats. The silverleaf whitefly (SLWF; Bemisia tabaci type B) is a good model for studying phloem-feeding insect-plant interactions, as SLWF ...

The biosynthesis of jasmonic acid (JA) in plant peroxisomes requires the action of acyl-coenzyme A oxidase (ACX). Among the five expressed members ( ACX1 – 5 ) of the ACX gene family in Arabidopsis ( Arabidopsis thaliana ), only ACX1 is known to serve a role in JA production. Here, we used ...

In a recent article, Lancien and Roberts ( Lancien M, Roberts MR [2006] Regulation of Arabidopsis thaliana 14-3-3 gene expression by γ -aminobutyric acid. Plant Cell Environ 29 : 1430–1436) reported that GABA influences the expression of 14-3-3 genes, which are important players in the ...

Insect eggs represent a threat for the plant as hatching larvae rapidly start with their feeding activity. Using a whole-genome microarray, we studied the expression profile of Arabidopsis ( Arabidopsis thaliana ) leaves after oviposition by two pierid butterflies. For Pieris brassicae , the ...

In conifer stems, formation of chemical defenses against insects or pathogens involves specialized anatomical structures of the phloem and xylem. Oleoresin terpenoids are formed in resin duct epithelial cells and phenolics accumulate in polyphenolic parenchyma cells. Ethylene signaling has been ...

We extend Ryan's seminal work on the 18-amino acid polypeptide systemin in tomato's ( Solanum lycopersicum ) systemic wound response to the closely related solanaceous species Solanum nigrum . We compared wild-type plants to plants transformed with an inverted repeat prosystemin construct (IR Sys ) ...

When Manduca sexta attacks Nicotiana attenuata , fatty acid-amino acid conjugates (FACs) in the larvae's oral secretions (OS) are introduced into feeding wounds. These FACs trigger a transcriptional response that is similar to the response induced by insect damage. Using two-dimensional gel ...

Proteinaceous aspartic proteinase inhibitors are rare in nature and are described in only a few plant species. One of them corresponds to a family of cathepsin D inhibitors (CDIs) described in potato ( Solanum tuberosum ), involving up to 15 isoforms with a high sequence similarity. In this work, ...

Astragalus bisulcatus and Stanleya pinnata hyperaccumulate selenium (Se) up to 1% of plant dry weight. In the field, Se was mostly present in the young leaves and reproductive tissues of both hyperaccumulators. Microfocused scanning x-ray fluorescence mapping revealed that Se was hyperaccumulated ...

Caterpillars of the herbivore Pieris rapae stimulate the production of jasmonic acid (JA) and ethylene (ET) in Arabidopsis ( Arabidopsis thaliana ) and trigger a defense response that affects insect performance on systemic tissues. To investigate the spectrum of effectiveness of P. rapae -induced ...

Calcium oxalate is the most abundant insoluble mineral found in plants and its crystals have been reported in more than 200 plant families. In the barrel medic Medicago truncatula Gaertn., these crystals accumulate predominantly in a sheath surrounding secondary veins of leaves. Mutants of M. ...

Germins and germin-like proteins (GLPs) are known to function in pathogen resistance, but their involvement in defense against insect herbivores is poorly understood. In the native tobacco Nicotiana attenuata , attack from the specialist herbivore Manduca sexta or elicitation by adding larval oral ...

In response to herbivore ( Spodoptera littoralis ) attack, lima bean ( Phaseolus lunatus ) leaves produced hydrogen peroxide (H 2 O 2 ) in concentrations that were higher when compared to mechanically damaged (MD) leaves. Cellular and subcellular localization analyses revealed that H 2 O 2 was ...

We analyzed the expression pattern of various terpene synthase ( TPS ) genes in response to a wounding injury applied to the apical leader of Sitka spruce ( Picea sitchensis Bong. Carr.) genotypes known to be resistant (R) or susceptible (S) to white pine weevil ( Pissodes strobi Peck.) attack. The ...