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Koramutla MK, Kaur A, Negi M, Venkatachalam P, Bhattacharya R. Elicitation of jasmonate-mediated host defense in Brassica juncea (L.) attenuates population growth of mustard aphid Lipaphis erysimi (Kalt.). PLANTA 2014; 240:177-94. [PMID: 24771023 DOI: 10.1007/s00425-014-2073-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 03/28/2014] [Indexed: 05/04/2023]
Abstract
The productivity of Brassica oilseeds is severely affected by its major pest: aphids. Unavailability of resistance source within the crossable germplasms has stalled the breeding efforts to derive aphid resistant cultivars. In this study, jasmonate-mediated host defense in Indian mustard Brassica juncea (L.) Czern. was evaluated and compared with regard to its elicitation in response to mustard aphid Lipaphis erysimi (Kalt.) and the defense elicitor methyl jasmonate (MeJ). Identification of jasmonate-induced unigenes in B. juncea revealed that most are orthologous to aphid-responsive genes, identified in taxonomically diverse plant-aphid interactions. The unigenes largely represented genes related to signal transduction, response to biotic and abiotic stimuli and homeostasis of reactive oxygen species (ROS), in addition to genes related to cellular and metabolic processes involved in cell organization, biogenesis, and development. Gene expression studies revealed induction of the key jasmonate biosynthetic genes (LOX, AOC, 12-OPDR), redox genes (CAT3 and GST6), and other downstream defense genes (PAL, ELI3, MYR, and TPI) by several folds, both in response to MeJ and plant-wounding. However, interestingly aphid infestation even after 24 h did not elicit any activation of these genes. In contrast, when the jasmonate-mediated host defense was elicited by exogenous application of MeJ the treated B. juncea plants showed a strong antibiosis effect on the infesting aphids and reduced the growth of aphid populations. The level of redox enzymes CAT, APX, and SOD, involved in ROS homeostasis in defense signaling, and several defense enzymes viz. POD, PPO, and PAL, remained high in treated plants. We conclude that in B. juncea, the jasmonate activated endogenous-defense, which is not effectively activated in response to mustard aphids, has the potential to reduce population growth of mustard aphids.
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Affiliation(s)
- Murali Krishna Koramutla
- National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute Campus, New Delhi, 110 012, India
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Mitra S, Baldwin IT. RuBPCase activase (RCA) mediates growth-defense trade-offs: silencing RCA redirects jasmonic acid (JA) flux from JA-isoleucine to methyl jasmonate (MeJA) to attenuate induced defense responses in Nicotiana attenuata. THE NEW PHYTOLOGIST 2014; 201:1385-1395. [PMID: 24491116 PMCID: PMC4996320 DOI: 10.1111/nph.12591] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 10/03/2013] [Indexed: 05/14/2023]
Abstract
• RuBPCase activase (RCA), an abundant photosynthetic protein, is strongly down-regulated in response to Manduca sexta's oral secretion (OS) in Nicotiana attenuata. RCA-silenced plants are impaired not only in photosynthetic capacity and growth, but also in jasmonic acid-isoleucine (JA-Ile) signaling, and herbivore resistance mediated by JA-Ile-dependent defense traits. These responses are consistent with a resource-based growth-defense trade-off. • As JA + Ile supplementation of OS restored wild-type (WT) levels of JA-Ile, defenses and resistance to M. sexta, but OS supplemented individually with JA or Ile did not, the JA-Ile deficiency of RCA-silenced plants could not be attributed to lower JA or Ile pools or JAR4/6 conjugating activity. Similar levels of JA-Ile derivatives after OS elicitation indicated unaltered JA-Ile turnover, and lower levels of other JA conjugates ruled out competition from other conjugation reactions. • RCA-silenced plants accumulated more methyl jasmonate (MeJA) after OS elicitation, which corresponded to increased jasmonate methyltransferase (JMT) activity. RCA silencing phenocopies JMT overexpression, wherein elevated JMT activity redirects OS-elicited JA flux towards inactive MeJA, creating a JA sink which depletes JA-Ile and its associated defense responses. • Hence, RCA plays an additional non-photosynthetic role in attenuating JA-mediated defenses and their associated costs, potentially allowing plants to anticipate resource-based constraints on growth before they actually occur.
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Affiliation(s)
- Sirsha Mitra
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany
| | - Ian T. Baldwin
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany
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Cao HH, Wang SH, Liu TX. Jasmonate- and salicylate-induced defenses in wheat affect host preference and probing behavior but not performance of the grain aphid, Sitobion avenae. INSECT SCIENCE 2014; 21:47-55. [PMID: 23956152 DOI: 10.1111/1744-7917.12023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/28/2013] [Indexed: 05/07/2023]
Abstract
Jasmonate- and salicylate-mediated signaling pathways play significant roles in induced plant defenses, but there is no sufficient evidence for their roles in monocots against aphids. We exogenously applied methyl jasmonate (MeJA) and salicylic acid (SA) on wheat seedlings and examined biochemical responses in wheat and effects on the grain aphid, Sitobion avenae (Fab.). Application of MeJA significantly increased levels of wheat's polyphenol oxidase, peroxidase and proteinase inhibitor 1, 2 and 6 days after treatment. In two-choice tests, adult aphids preferred control wheat leaves to MeJA- or SA-treated leaves. Electrical penetration graph (EPG) recordings of aphid probing behavior revealed that on MeJA-treated plants, the duration of aphid's first probe was significantly shorter and number of probes was significantly higher than those on control plants. Also total duration of probing on MeJA-treated plants was significantly shorter than on control plants. Total duration of salivation period on SA-treated plants was significantly longer, while mean phloem ingestion period was significantly shorter than on control plants. However, no significant difference in total duration of phloem sap ingestion period was observed among treatments. The EPG data suggest that MeJA-dependent resistance factors might be due to feeding deterrents in mesophyll, whereas the SA-mediated resistance may be phloem-based. We did not observe any significant difference of MeJA and SA application on aphid development, daily fecundity, intrinsic growth rate and population growth. The results indicate that both MeJA- and SA-induced defenses in wheat deterred S. avenae colonization processes and feeding behavior, but had no significant effects on its performance.
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Affiliation(s)
- He-He Cao
- State Key Laboratory of Crop Stress Biology on the Arid Areas, and the Key Laboratory of Crop Pest Management on the Losses Plateau of Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China
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54
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Lan Z, Krosse S, Achard P, van Dam NM, Bede JC. DELLA proteins modulate Arabidopsis defences induced in response to caterpillar herbivory. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:571-83. [PMID: 24399173 PMCID: PMC3904718 DOI: 10.1093/jxb/ert420] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Upon insect herbivory, many plant species change the direction of metabolic flux from growth into defence. Two key pathways modulating these processes are the gibberellin (GA)/DELLA pathway and the jasmonate pathway. In this study, the effect of caterpillar herbivory on plant-induced responses was compared between wild-type Arabidopsis thaliana (L.) Heynh. and quad-della mutants that have constitutively elevated GA responses. The labial saliva (LS) of caterpillars of the beet armyworm, Spodoptera exigua, is known to influence induced plant defence responses. To determine the role of this herbivore cue in determining metabolic shifts, plants were subject to herbivory by caterpillars with intact or impaired LS secretions. In both wild-type and quad-della plants, a jasmonate burst is an early response to caterpillar herbivory. Negative growth regulator DELLA proteins are required for the LS-mediated suppression of hormone levels. Jasmonate-dependent marker genes are induced in response to herbivory independently of LS, with the exception of AtPDF1.2 that showed LS-dependent expression in the quad-della mutant. Early expression of the salicylic acid (SA)-marker gene, AtPR1, was not affected by herbivory which also reflected SA hormone levels; however, this gene showed LS-dependent expression in the quad-della mutant. DELLA proteins may positively regulate glucosinolate levels and suppress laccase-like multicopper oxidase activity in response to herbivory. The present results show a link between DELLA proteins and early, induced plant defences in response to insect herbivory; in particular, these proteins are necessary for caterpillar LS-associated attenuation of defence hormones.
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Affiliation(s)
- Zhiyi Lan
- Department of Plant Science, McGill University, 21111 Lakeshore, Ste-Anne-de-Belleuve, QC, H9X 3V9, Canada
| | - Sebastian Krosse
- Ecogenomics, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Patrick Achard
- Institut de Biologie Moléculare des Plantes, Université de Strasbourg, Strasbourg, France
| | - Nicole M. van Dam
- Ecogenomics, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Jacqueline C. Bede
- Department of Plant Science, McGill University, 21111 Lakeshore, Ste-Anne-de-Belleuve, QC, H9X 3V9, Canada
- * To whom correspondence should be addressed. E-mail:
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Wang L, Wu J. The essential role of jasmonic acid in plant-herbivore interactions--using the wild tobacco Nicotiana attenuata as a model. J Genet Genomics 2013; 40:597-606. [PMID: 24377866 DOI: 10.1016/j.jgg.2013.10.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 10/15/2013] [Accepted: 10/16/2013] [Indexed: 12/28/2022]
Abstract
The plant hormone jasmonic acid (JA) plays a central role in plant defense against herbivores. Herbivore damage elicits a rapid and transient JA burst in the wounded leaves and JA functions as a signal to mediate the accumulation of various secondary metabolites that confer resistance to herbivores. Nicotiana attenuata is a wild tobacco species that inhabits western North America. More than fifteen years of study and its unique interaction with the specialist herbivore insect Manduca sexta have made this plant one of the best models for studying plant-herbivore interactions. Here we review the recent progress in understanding the elicitation of JA accumulation by herbivore-specific elicitors, the regulation of JA biosynthesis, JA signaling, and the herbivore-defense traits in N. attenuata.
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Affiliation(s)
- Lei Wang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Jianqiang Wu
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
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Ullmann-Zeunert L, Stanton MA, Wielsch N, Bartram S, Hummert C, Svatoš A, Baldwin IT, Groten K. Quantification of growth-defense trade-offs in a common currency: nitrogen required for phenolamide biosynthesis is not derived from ribulose-1,5-bisphosphate carboxylase/oxygenase turnover. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 75:417-429. [PMID: 23590461 PMCID: PMC4996319 DOI: 10.1111/tpj.12210] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 04/03/2013] [Accepted: 04/11/2013] [Indexed: 05/20/2023]
Abstract
Induced defenses are thought to be economical: growth and fitness-limiting resources are only invested into defenses when needed. To date, this putative growth-defense trade-off has not been quantified in a common currency at the level of individual compounds. Here, a quantification method for ¹⁵N-labeled proteins enabled a direct comparison of nitrogen (N) allocation to proteins, specifically, ribulose-1,5-bisposphate carboxylase/oxygenase (RuBisCO), as proxy for growth, with that to small N-containing defense metabolites (nicotine and phenolamides), as proxies for defense after herbivory. After repeated simulated herbivory, total N decreased in the shoots of wild-type (WT) Nicotiana attenuata plants, but not in two transgenic lines impaired in jasmonate defense signaling (irLOX3) and phenolamide biosynthesis (irMYB8). N was reallocated among different compounds within elicited rosette leaves: in the WT, a strong decrease in total soluble protein (TSP) and RuBisCO was accompanied by an increase in defense metabolites, irLOX3 showed a similar, albeit attenuated, pattern, whereas irMYB8 rosette leaves were the least responsive to elicitation, with overall higher levels of RuBisCO. Induced defenses were higher in the older compared with the younger rosette leaves, supporting the hypothesis that tissue developmental stage influences defense investments. We propose that MYB8, probably by regulating the production of phenolamides, indirectly mediates protein pool sizes after herbivory. Although the decrease in absolute N invested in TSP and RuBisCO elicited by simulated herbivory was much larger than the N-requirements of nicotine and phenolamide biosynthesis, ¹⁵N flux studies revealed that N for phenolamide synthesis originates from recently assimilated N, rather than from RuBisCO turnover.
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Affiliation(s)
- Lynn Ullmann-Zeunert
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena
- Qiagen, Hilden
| | - Mariana A. Stanton
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena
| | | | - Stefan Bartram
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Jena
| | - Christian Hummert
- Systems Biology/Bioinformatics Research Group, Leibniz Institute for Natural Product Research and Infection Biology, Jena
| | - Aleš Svatoš
- MS Group, Max Planck Institute for Chemical Ecology, Jena
| | - Ian T. Baldwin
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena
| | - Karin Groten
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena
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Yang DH, Baldwin IT, Wu J. Silencing brassinosteroid receptor BRI1 impairs herbivory-elicited accumulation of jasmonic acid-isoleucine and diterpene glycosides, but not jasmonic acid and trypsin proteinase inhibitors in Nicotiana attenuata. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:514-526. [PMID: 23347255 DOI: 10.1111/jipb.12035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 01/21/2013] [Indexed: 06/01/2023]
Abstract
The brassinosteroid (BR) receptor, BR insensitive 1 (BRI1), plays a critical role in plant development, but whether BRI1-mediated BR signaling is involved in plant defense responses to herbivores was largely unknown. Here, we examined the function of BRI1 in the resistance of Nicotiana attenuata (Solanaceae) to its specialist insect herbivore Manduca sexta. Jasmonic acid (JA) and JA-isoleucine conjugate (JA-Ile) are important hormones that mediate resistance to herbivores and we found that after wounding or simulated herbivory NaBRI1 had little effect on JA levels, but was important for the induction of JA-Ile. Further experiments revealed that decreased JAR (the enzyme for JA-Ile production) activity and availability of Ile in NaBRI1-silenced plants were likely responsible for the low JA-Ile levels. Consistently, M. sexta larvae gained more weight on NaBRI1-silenced plants than on the control plants. Quantification of insect feeding-induced secondary metabolites revealed that silencing NaBRI1 resulted in decreased levels of carbon-rich defensive secondary metabolites (hydroxygeranyllinalool diterpene glycosides, chlorogenic acid, and rutin), but had little effect on the nitrogen-rich ones (nicotine and trypsin proteinase inhibitors). Thus, NaBRI1-mediated BR signaling is likely involved in plant defense responses to M. sexta, including maintaining JA-Ile levels and the accumulation of several carbon-rich defensive secondary metabolites.
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Affiliation(s)
- Da-Hai Yang
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll Straße 8, D-07745 Jena, Germany
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58
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Bode RF, Halitschke R, Kessler A. Herbivore damage-induced production and specific anti-digestive function of serine and cysteine protease inhibitors in tall goldenrod, Solidago altissima L. (Asteraceae). PLANTA 2013; 237:1287-1296. [PMID: 23371287 DOI: 10.1007/s00425-013-1845-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 01/13/2013] [Indexed: 06/01/2023]
Abstract
Plant protease inhibitors (PIs) are among the most well-studied and widely distributed resistance traits that plants use against their herbivore attackers. There are different types of plant PIs which putatively function against the different types of proteases expressed in insect guts. Serine protease inhibitors (SPIs) and cysteine protease inhibitors (CPIs) are hypothesized to differentially function against the predominant gut proteases in lepidopteran and coleopteran herbivores, respectively. Here, we test the hypothesis that tall goldenrod, Solidago altissima, can specifically respond to damage by different herbivores and differentially induce SPIs and CPIs in response to damage by lepidopteran and coleopteran herbivores. Moreover, we ask if the concerted induction of different types of PIs accounts for variation in induced resistance to herbivory. We altered and optimized a rapid and effective existing methodology to quantitatively analyze both SPI and CPI activity simultaneously from a single tissue sample and to use the same plant extracts directly for characterization of inhibitory effects on insect gut protease activity. We found that both SPIs and CPIs are induced in S. altissima in response to damage, regardless of the damaging herbivore species. However, only SPIs were effective against Spodoptera exigua gut proteases. Our data suggest that plant PI responses are not necessarily specific to the identity of the attacking organism but that different components of generally induced defense traits can specifically affect different herbivore species. While providing an efficient and broadly applicable methodology to analyze multiple PIs extracted from the same tissue, this study furthers our understanding of specificity in induced plant resistance.
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Affiliation(s)
- Robert F Bode
- Department of Ecology and Evolutionary Biology, Cornell University, E445 Corson Hall, Ithaca, NY 14853, USA
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Wu J, Wang L, Wünsche H, Baldwin IT. Narboh D, a respiratory burst oxidase homolog in Nicotiana attenuata, is required for late defense responses after herbivore attack. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:187-98. [PMID: 23116134 DOI: 10.1111/j.1744-7909.2012.01182.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The superoxide (O₂⁻)-generating NADPH oxidases are crucial for the defense of plants against attack from pathogens; however, it remains unknown whether they also mediate responses against chewing insect herbivores. The transcripts of the respiratory burst NADPH oxidase homolog Narboh D in Nicotiana attenuate are rapidly and transiently elicited by wounding, and are amplified when Manduca sexta oral secretions (OS) are added to the wounds. The fatty-acid-amino-acid-conjugates (FACs), demonstrably the major elicitors in M. sexta OS, are responsible for the increase in Narboh D transcripts. Silencing Narboh D significantly reduced reactive oxygen species (ROS) levels after OS elicitation, but neither OS-elicited jasmonic acid (JA) or JA-isoleucine (JA-Ile) bursts, pivotal hormones that regulates plant resistance to herbivores, nor early transcripts of herbivore defense-related genes (NaJAR4 and NaPAL1), were influenced. However, late OS-elicited increases in trypsin proteinase inhibitors (TPIs), as well as the transcript levels of defense genes such as polyphenol oxidase, TPI and Thionin were significantly reduced. In addition, Narboh D-silenced plants were more vulnerable to insect herbivores, especially the larvae of the generalist Spodoptera littoralis. We thus conclude that Narboh D-based defenses play an important role in late herbivore-elicited responses.
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Affiliation(s)
- Jinsong Wu
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Science, Lanhei Road 132, China
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Zavala JA, Nabity PD, DeLucia EH. An emerging understanding of mechanisms governing insect herbivory under elevated CO2. ANNUAL REVIEW OF ENTOMOLOGY 2013; 58:79-97. [PMID: 22974069 DOI: 10.1146/annurev-ento-120811-153544] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
By changing the chemical composition of foliage, the increase in atmospheric CO(2) is fundamentally altering insect herbivory. The responses of folivorous insects to these changes is, however, highly variable. In this review we highlight emerging mechanisms by which increasing CO(2) alters the defense chemistry and signaling of plants. The response of allelochemicals affecting insect performance varies under elevated CO(2), and results suggest this is driven by changes in plant hormones. Increasing CO(2) suppresses the production of jasmonates and ethylene and increases the production of salicylic acid, and these differential responses of plant hormones affect specific secondary chemical pathways. In addition to changes in secondary chemistry, elevated CO(2) decreases rates of water loss from leaves, increases temperature and feeding rates, and alters nutritional content. New insights into the mechanistic responses of secondary chemistry to elevated CO(2) increase our ability to predict the ecological and evolutionary responses of plants attacked by insects.
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Affiliation(s)
- Jorge A Zavala
- Cátedra de Bioquímica/INBA, Facultad de Agronomía, University of Buenos Aires-CONICET, Buenos Aires C1417DSE, Argentina.
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Nair M, Sandhu SS. A Kunitz trypsin inhibitor from chickpea (<i>Cicer arietinum</i> L.) that exerts an antimicrobial effect on Fusarium oxysporum f.sp. ciceris. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/as.2013.411079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Gaquerel E, Stitz M, Kallenbach M, Baldwin IT. Jasmonate signaling in the field, part II: insect-guided characterization of genetic variations in jasmonate-dependent defenses of transgenic and natural Nicotiana attenuata populations. Methods Mol Biol 2013; 1011:97-109. [PMID: 23615990 DOI: 10.1007/978-1-62703-414-2_8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The introduction of genetically modified plants into natural habitats represents a valuable means to determine organismic level functions of a gene and its effects on a plant's interaction with other organisms. Nicotiana attenuata, a wild tobacco species native of the southwestern USA that grows in the immediate postfire environment, is one of the important host plants for herbivore populations recolonizing recently burned habitats in the Great Basin Desert. Here, we provide detailed guidelines for the analysis, under field conditions, of jasmonate-dependent defense and its impact on the plant's native herbivore community. The procedures are based on the field release of transgenic lines silenced for jasmonate biogenesis, metabolism, or perception to conduct association studies between defense trait expression (secondary metabolite and trypsin proteinase inhibitor accumulation) and insect infestations. Additionally, because some insects have evolved mechanisms to "eavesdrop" on jasmonate signaling when selecting their host plants, we describe how leafhoppers of the species Empoasca, which selectively colonize jasmonate-deficient plants, can be used as "bloodhounds" for identifying natural variations in jasmonate signaling among natural N. attenuata populations.
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Affiliation(s)
- Emmanuel Gaquerel
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena, Germany
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Joshi RS, Mishra M, Tamhane VA, Ghosh A, Sonavane U, Suresh CG, Joshi R, Gupta VS, Giri AP. The remarkable efficiency of a Pin-II proteinase inhibitor sans two conserved disulfide bonds is due to enhanced flexibility and hydrogen bond density in the reactive site loop. J Biomol Struct Dyn 2012; 32:13-26. [PMID: 23256852 DOI: 10.1080/07391102.2012.745378] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Capsicum annuum (L.) expresses diverse potato type II family proteinase inhibitors comprising of inhibitory repeat domain (IRD) as basic functional unit. Most IRDs contain eight conserved cysteines forming four disulfide bonds, which are indispensible for their stability and activity. We investigated the functional significance of evolutionary variations in IRDs and their role in mediating interaction between the inhibitor and cognate proteinase. Among the 18 IRDs encoded by C. annuum, IRD-7, -9, and -12 were selected for further characterization on the basis of variation in their reactive site loop, number of conserved cysteine residues, and higher theoretical ΔGbind for interaction with Helicoverpa armigera trypsin. Moreover, inhibition kinetics showed that IRD-9, despite loss of some of the disulfide bonds, was a more potent proteinase inhibitor among the three selected IRDs. Molecular dynamic simulations revealed that serine residues in the place of cysteines at seventh and eighth positions of IRD-9 resulted in an increase in the density of intramolecular hydrogen bonds and reactive site loop flexibility. Results of the serine residues chemical modification also supported this observation and provided a possible explanation for the remarkable inhibitory potential of IRD-9. Furthermore, this natural variant among IRDs showed special attributes like stability to proteolysis and synergistic inhibitory effect on other IRDs. It is likely that IRDs have coevolved selective specialization of their structure and function as a response towards specific insect proteases they encountered. Understanding the molecular mechanism of pest protease-plant proteinaceous inhibitor interaction will help in developing effective pest control strategies. An animated interactive 3D complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:JBSD:39.
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Affiliation(s)
- Rakesh S Joshi
- a Plant Molecular Biology Unit, Biochemical Sciences Division , CSIR-National Chemical Laboratory , Dr. Homi Bhabha Road, Pune , 411 008 , MS , India
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Meldau S, Erb M, Baldwin IT. Defence on demand: mechanisms behind optimal defence patterns. ANNALS OF BOTANY 2012; 110:1503-14. [PMID: 23022676 PMCID: PMC3503495 DOI: 10.1093/aob/mcs212] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 08/22/2012] [Indexed: 05/20/2023]
Abstract
BACKGROUND The optimal defence hypothesis (ODH) predicts that tissues that contribute most to a plant's fitness and have the highest probability of being attacked will be the parts best defended against biotic threats, including herbivores. In general, young sink tissues and reproductive structures show stronger induced defence responses after attack from pathogens and herbivores and contain higher basal levels of specialized defensive metabolites than other plant parts. However, the underlying physiological mechanisms responsible for these developmentally regulated defence patterns remain unknown. SCOPE This review summarizes current knowledge about optimal defence patterns in above- and below-ground plant tissues, including information on basal and induced defence metabolite accumulation, defensive structures and their regulation by jasmonic acid (JA). Physiological regulations underlying developmental differences of tissues with contrasting defence patterns are highlighted, with a special focus on the role of classical plant growth hormones, including auxins, cytokinins, gibberellins and brassinosteroids, and their interactions with the JA pathway. By synthesizing recent findings about the dual roles of these growth hormones in plant development and defence responses, this review aims to provide a framework for new discoveries on the molecular basis of patterns predicted by the ODH. CONCLUSIONS Almost four decades after its formulation, we are just beginning to understand the underlying molecular mechanisms responsible for the patterns of defence allocation predicted by the ODH. A requirement for future advances will be to understand how developmental and defence processes are integrated.
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Affiliation(s)
- Stefan Meldau
- Department of Molecular Ecology, Max-Planck-Institute for Chemical Ecology, Jena, Germany.
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Woldemariam MG, Onkokesung N, Baldwin IT, Galis I. Jasmonoyl-L-isoleucine hydrolase 1 (JIH1) regulates jasmonoyl-L-isoleucine levels and attenuates plant defenses against herbivores. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 72:758-67. [PMID: 22860609 DOI: 10.1111/j.1365-313x.2012.05117.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
For most plant hormones, biological activity is suppressed by reversible conjugation to sugars, amino acids and other small molecules. In contrast, the conjugation of jasmonic acid (JA) to isoleucine (Ile) is known to enhance the activity of JA. Whereas hydroxylation and carboxylation of JA-Ile permanently inactivates JA-Ilemediated signaling in plants, the alternative deactivation pathway of JA-Ile by its direct hydrolysis to JA remains unstudied. We show that Nicotiana attenuata jasmonoyl-L-isoleucine hydrolase 1 (JIH1), a close homologue of previously characterized indoleacetic acid alanine resistant 3 (IAR3) gene in Arabidopsis, hydrolyzes both JA-Ile and IAA-Ala in vitro. When the herbivory-inducible NaJIH1 gene was silenced by RNA interference, JA-Ile levels increased dramatically after simulated herbivory in irJIH1, compared with wild-type (WT) plants. When specialist (Manduca sexta) or generalist (Spodoptera littoralis) herbivores fed on irJIH1 plants they gained significantly less mass compared with those feeding on wild-type (WT) plants. The poor larval performance was strongly correlated with the higher accumulation of several JA-Ile-dependent direct defense metabolites in irJIH1 plants. In the field, irJIH1 plants attracted substantially more Geocoris predators to the experimentally attached M. sexta eggs on their leaves, compared with empty vector plants, which correlated with higher herbivory-elicited emissions of volatiles known to function as indirect defenses. We conclude that NaJIH1 encodes a new homeostatic step in JA metabolism that, together with JA and JA-Ilehydroxylation and carboxylation of JA-Ile, rapidly attenuates the JA-Ile burst, allowing plants to tailor the expression of direct and indirect defenses against herbivore attack in nature.
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Affiliation(s)
- Melkamu G Woldemariam
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans Knöll Str. 8, Jena D-07745, Germany
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Yang DH, Hettenhausen C, Baldwin IT, Wu J. Silencing Nicotiana attenuata calcium-dependent protein kinases, CDPK4 and CDPK5, strongly up-regulates wound- and herbivory-induced jasmonic acid accumulations. PLANT PHYSIOLOGY 2012; 159:1591-607. [PMID: 22715110 PMCID: PMC3425199 DOI: 10.1104/pp.112.199018] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 06/14/2012] [Indexed: 05/18/2023]
Abstract
The plant hormone jasmonic acid (JA) plays a pivotal role in plant-insect interactions. Herbivore attack usually elicits dramatic increases in JA concentrations, which in turn activate the accumulation of metabolites that function as defenses against herbivores. Although almost all enzymes involved in the biosynthesis pathway of JA have been identified and characterized, the mechanism by which plants regulate JA biosynthesis remains unclear. Calcium-dependent protein kinases (CDPKs) are plant-specific proteins that sense changes in [Ca(2+)] to activate downstream responses. We created transgenic Nicotiana attenuata plants, in which two CDPKs, NaCDPK4 and NaCDPK5, were simultaneously silenced (IRcdpk4/5 plants). IRcdpk4/5 plants were stunted and aborted most of their flower primordia. Importantly, after wounding or simulated herbivory, IRcdpk4/5 plants accumulated exceptionally high JA levels. When NaCDPK4 and NaCDPK5 were silenced individually, neither stunted growth nor high JA levels were observed, suggesting that NaCDPK4 and NaCDPK5 have redundant roles. Attack from Manduca sexta larvae on IRcdpk4/5 plants induced high levels of defense metabolites that slowed M. sexta growth. We found that NaCDPK4 and NaCDPK5 affect plant resistance against insects in a JA- and JA-signaling-dependent manner. Furthermore, IRcdpk4/5 plants showed overactivation of salicylic-acid-induced protein kinase, a mitogen-activated protein kinase involved in various stress responses, and genetic analysis indicated that the increased salicylic-acid-induced protein kinase activity in IRcdpk4/5 plants was a consequence of the exceptionally high JA levels and was dependent on CORONATINE INSENSITIVE1. This work reveals the critical roles of CDPKs in modulating JA homeostasis and highlights the complex duet between JA and mitogen-activated protein kinase signaling.
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Affiliation(s)
| | | | - Ian T. Baldwin
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
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Curzi MJ, Zavala JA, Spencer JL, Seufferheld MJ. Abnormally high digestive enzyme activity and gene expression explain the contemporary evolution of a Diabrotica biotype able to feed on soybeans. Ecol Evol 2012; 2:2005-17. [PMID: 22957201 PMCID: PMC3434003 DOI: 10.1002/ece3.331] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 06/12/2012] [Accepted: 06/19/2012] [Indexed: 12/02/2022] Open
Abstract
Western corn rootworm (Diabrotica virgifera) (WCR) depends on the continuous availability of corn. Broad adoption of annual crop rotation between corn (Zea mays) and nonhost soybean (Glycine max) exploited WCR biology to provide excellent WCR control, but this practice dramatically reduced landscape heterogeneity in East-central Illinois and imposed intense selection pressure. This selection resulted in behavioral changes and “rotation-resistant” (RR) WCR adults. Although soybeans are well defended against Coleopteran insects by cysteine protease inhibitors, RR-WCR feed on soybean foliage and remain long enough to deposit eggs that will hatch the following spring and larvae will feed on roots of planted corn. Other than documenting changes in insect mobility and egg laying behavior, 15 years of research have failed to identify any diagnostic differences between wild-type (WT)- and RR-WCR or a mechanism that allows for prolonged RR-WCR feeding and survival in soybean fields. We documented differences in behavior, physiology, digestive protease activity (threefold to fourfold increases), and protease gene expression in the gut of RR-WCR adults. Our data suggest that higher constitutive activity levels of cathepsin L are part of the mechanism that enables populations of WCR to circumvent soybean defenses, and thus, crop rotation. These new insights into the mechanism of WCR tolerance of soybean herbivory transcend the issue of RR-WCR diagnostics and management to link changes in insect gut proteolytic activity and behavior with landscape heterogeneity. The RR-WCR illustrates how agro-ecological factors can affect the evolution of insects in human-altered ecosystems.
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von Elert E, Zitt A, Schwarzenberger A. Inducible tolerance to dietary protease inhibitors in Daphnia magna. J Exp Biol 2012; 215:2051-9. [DOI: 10.1242/jeb.068742] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Daphnia has been shown to acquire tolerance to cyanobacterial toxins within an animals' lifetime and to transfer this tolerance to the next generation. Here we used a strain of the cyanobacterium Microcystis aeruginosa, which contained two chymotrypsin inhibitors (BN920 and CP954), the green alga Scenedesmus obliquus as reference food and a clone of D. magna to investigate the physiological mechanism of acquired tolerance to these cyanobacterial toxins. The intracellular concentrations of CP954 and BN920 were 1550 and 120 μmol l–1, respectively. When food suspensions of the green alga contained >60% M. aeruginosa, growth rates of D. magna were reduced. When grown on the green alga, three chymotrypsins ranging in mass from 16 to 22 kDa were distinguished in D. magna. Purified BN920 and CP954 specifically inhibited D. magna chymotrypsins. Feeding with encapsulated BN920 resulted in growth depression in D. magna and replacement of the chymotrypsins by three chymotrypsins with smaller molecular mass. With just 20% M. aeruginosa, the same changes in the chymotrypsin pattern as with the pure inhibitor were observed. IC50 values for inhibition of chymotrypsins of D. magna growing on the green alga were 5.4 nmol l–1 (BN920) and 7.4 nmol l–1 (CP954). When D. magna was grown on 20% M. aeruginosa, 2.2-fold higher IC50 values were observed. This indicated that increased tolerance to these dietary inhibitors was acquired within an animal's lifetime by remodelling the digestive chymotrypsins, which in turn serves as an intra-generational defence against these cyanobacterial inhibitors. This mechanism might be relevant for the transfer of tolerance to the next generation through maternal effects.
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Affiliation(s)
- Eric von Elert
- Zoological Institute, Cologne Biocenter, University of Cologne, Köln, Germany
| | - Anja Zitt
- Department of Chemistry, University of Konstanz, Konstanz, Germany
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Oh Y, Baldwin IT, Gális I. NaJAZh regulates a subset of defense responses against herbivores and spontaneous leaf necrosis in Nicotiana attenuata plants. PLANT PHYSIOLOGY 2012; 159:769-88. [PMID: 22496510 PMCID: PMC3375940 DOI: 10.1104/pp.112.193771] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 04/05/2012] [Indexed: 05/18/2023]
Abstract
The JASMONATE ZIM DOMAIN (JAZ) proteins function as negative regulators of jasmonic acid signaling in plants. We cloned 12 JAZ genes from native tobacco (Nicotiana attenuata), including nine novel JAZs in tobacco, and examined their expression in plants that had leaves elicited by wounding or simulated herbivory. Most JAZ genes showed strong expression in the elicited leaves, but NaJAZg was mainly expressed in roots. Another novel herbivory-elicited gene, NaJAZh, was analyzed in detail. RNA interference suppression of this gene in inverted-repeat (ir)JAZh plants deregulated a specific branch of jasmonic acid-dependent direct and indirect defenses: irJAZh plants showed greater trypsin protease inhibitor activity, 17-hydroxygeranyllinalool diterpene glycosides accumulation, and emission of volatile organic compounds from leaves. Silencing of NaJAZh also revealed a novel cross talk in JAZ-regulated secondary metabolism, as irJAZh plants had significantly reduced nicotine levels. In addition, irJAZh spontaneously developed leaf necrosis during the transition to flowering. Because the lesions closely correlated with the elevated expression of programmed cell death genes and the accumulations of salicylic acid and hydrogen peroxide in the leaves, we propose a novel role of the NaJAZh protein as a repressor of necrosis and/or programmed cell death during plant development.
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Affiliation(s)
- Youngjoo Oh
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena D–07745, Germany
| | - Ian T. Baldwin
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena D–07745, Germany
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Ye M, Luo SM, Xie JF, Li YF, Xu T, Liu Y, Song YY, Zhu-Salzman K, Zeng RS. silencing COI1 in rice increases susceptibility to chewing insects and impairs inducible defense. PLoS One 2012; 7:e36214. [PMID: 22558386 PMCID: PMC3338713 DOI: 10.1371/journal.pone.0036214] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 03/28/2012] [Indexed: 11/24/2022] Open
Abstract
The jasmonic acid (JA) pathway plays a key role in plant defense responses against herbivorous insects. CORONATINE INSENSITIVE1 (COI1) is an F-box protein essential for all jasmonate responses. However, the precise defense function of COI1 in monocotyledonous plants, especially in rice (Oryza sativa L.) is largely unknown. We silenced OsCOI1 in rice plants via RNA interference (RNAi) to determine the role of OsCOI1 in rice defense against rice leaf folder (LF) Cnaphalocrocis medinalis, a chewing insect, and brown planthopper (BPH) Nilaparvata lugens, a phloem-feeding insect. In wild-type rice plants (WT), the transcripts of OsCOI1 were strongly and continuously up-regulated by LF infestation and methyl jasmonate (MeJA) treatment, but not by BPH infestation. The abundance of trypsin protease inhibitor (TrypPI), and the enzymatic activities of polyphenol oxidase (PPO) and peroxidase (POD) were enhanced in response to both LF and BPH infestation, but the activity of lipoxygenase (LOX) was only induced by LF. The RNAi lines with repressed expression of OsCOI1 showed reduced resistance against LF, but no change against BPH. Silencing OsCOI1 did not alter LF-induced LOX activity and JA content, but it led to a reduction in the TrypPI content, POD and PPO activity by 62.3%, 48.5% and 27.2%, respectively. In addition, MeJA-induced TrypPI and POD activity were reduced by 57.2% and 48.2% in OsCOI1 RNAi plants. These results suggest that OsCOI1 is an indispensable signaling component, controlling JA-regulated defense against chewing insect (LF) in rice plants, and COI1 is also required for induction of TrypPI, POD and PPO in rice defense response to LF infestation.
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Affiliation(s)
- Mao Ye
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-bioresources, Ministry of Agriculture, South China Agricultural University, Wushan, Guangzhou, People's Republic of China
- Key Laboratory of Tropical Agro-environment, Ministry of Agriculture, South China Agricultural University, Wushan, Guangzhou, People's Republic of China
| | - Shi Ming Luo
- Key Laboratory of Tropical Agro-environment, Ministry of Agriculture, South China Agricultural University, Wushan, Guangzhou, People's Republic of China
| | - Jie Fen Xie
- Key Laboratory of Tropical Agro-environment, Ministry of Agriculture, South China Agricultural University, Wushan, Guangzhou, People's Republic of China
| | - Yan Fang Li
- Plant Protection Institute, Guangdong Academy of Agricultural Sciences of China, Guangzhou, People's Republic of China
| | - Tao Xu
- Key Laboratory of Tropical Agro-environment, Ministry of Agriculture, South China Agricultural University, Wushan, Guangzhou, People's Republic of China
| | - Yang Liu
- College of Life Sciences, South China Agricultural University, Wushan, Guangzhou, People's Republic of China
| | - Yuan Yuan Song
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-bioresources, Ministry of Agriculture, South China Agricultural University, Wushan, Guangzhou, People's Republic of China
- Key Laboratory of Tropical Agro-environment, Ministry of Agriculture, South China Agricultural University, Wushan, Guangzhou, People's Republic of China
| | - Keyan Zhu-Salzman
- Department of Entomology, Texas A&M University, College Station, Texas, United States of America
| | - Ren Sen Zeng
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-bioresources, Ministry of Agriculture, South China Agricultural University, Wushan, Guangzhou, People's Republic of China
- Key Laboratory of Tropical Agro-environment, Ministry of Agriculture, South China Agricultural University, Wushan, Guangzhou, People's Republic of China
- * E-mail:
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71
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Fan R, Wang H, Wang Y, Yu D. Proteomic analysis of soybean defense response induced by cotton worm (prodenia litura, fabricius) feeding. Proteome Sci 2012; 10:16. [PMID: 22397523 PMCID: PMC3325874 DOI: 10.1186/1477-5956-10-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 03/08/2012] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Cotton worm is one of the main insects of soybean in southern China. Plants may acquire defense mechanisms that confer protection from predation by herbivores. Induced responses can lead to increased resistance against herbivores in many species. This study focuses on searching changed proteins in soybean defense response induced by cotton worm feeding. RESULTS Ten protein spots that are changed in abundance in response to cotton worm feeding were identified by Two-dimensional gel electrophoresis (2-DE). A total of 11 unique proteins from these spots were identified by MALDI-TOF MS. The mRNA and protein relative expression levels of most changed proteins were up-regulated. These proteins were mainly involved in physiological processes, including active oxygen removal, defense signal transduction, and metabolism regulation. CONCLUSION This is the first proteomic analysis of the soybean defense response induced by cotton worm. The differentially expressed proteins could work together to play a major role in the induced defense response. PAL and SAMS were up-regulated at both the protein and mRNA levels. These genes can be strongest candidates for further functional research.
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Affiliation(s)
- Rui Fan
- National Center for Soybean Improvement, National Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
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Abstract
Plants have evolved a plethora of different chemical defenses covering nearly all classes of (secondary) metabolites that represent a major barrier to herbivory: Some are constitutive; others are induced after attack. Many compounds act directly on the herbivore, whereas others act indirectly via the attraction of organisms from other trophic levels that, in turn, protect the plant. An enormous diversity of plant (bio)chemicals are toxic, repellent, or antinutritive for herbivores of all types. Examples include cyanogenic glycosides, glucosinolates, alkaloids, and terpenoids; others are macromolecules and comprise latex or proteinase inhibitors. Their modes of action include membrane disruption, inhibition of nutrient and ion transport, inhibition of signal transduction processes, inhibition of metabolism, or disruption of the hormonal control of physiological processes. Recognizing the herbivore challenge and precise timing of plant activities as well as the adaptive modulation of the plants' metabolism is important so that metabolites and energy may be efficiently allocated to defensive activities.
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Affiliation(s)
- Axel Mithöfer
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Jena, Germany.
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74
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Bonaventure G. The Nicotiana attenuata LECTIN RECEPTOR KINASE 1 is involved in the perception of insect feeding. PLANT SIGNALING & BEHAVIOR 2011; 6:2060-3. [PMID: 22105024 PMCID: PMC3356243 DOI: 10.4161/psb.6.12.18324] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The Nicotiana attenuata LECTIN RECEPTOR KINASE 1 (LecRK1) has been recently identified as a component of the mechanism used by plants to suppress the Manduca sexta-triggered accumulation of salicylic acid (SA). The suppression of the SA burst by LecRK1 allows for the unfettered induction of jasmonic acid (JA)-mediated defense responses against M. sexta herbivory. LecRK1 contains a multi-domain extracellular region composed of a G-type Lectin domain and a PAN-AP domain separated by a variable sequence with low similarity to an EGF domain. The LecRK1 intracellular region is composed of a single domain structure with predicted Ser/Thr protein kinase activity. The multi-domain structure of the extracellular region of LecRK1 adds a level of complexity in terms of the potential ligands that this receptor protein could recognize.
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Affiliation(s)
- Gustavo Bonaventure
- Max Planck Institute of Chemical Ecology, Department of Molecular Ecology, Jena, Germany.
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Azarkan M, Martinez-Rodriguez S, Buts L, Baeyens-Volant D, Garcia-Pino A. The plasticity of the β-trefoil fold constitutes an evolutionary platform for protease inhibition. J Biol Chem 2011; 286:43726-43734. [PMID: 22027836 DOI: 10.1074/jbc.m111.291310] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteases carry out a number of crucial functions inside and outside the cell. To protect the cells against the potentially lethal activities of these enzymes, specific inhibitors are produced to tightly regulate the protease activity. Independent reports suggest that the Kunitz-soybean trypsin inhibitor (STI) family has the potential to inhibit proteases with different specificities. In this study, we use a combination of biophysical methods to define the structural basis of the interaction of papaya protease inhibitor (PPI) with serine proteases. We show that PPI is a multiple-headed inhibitor; a single PPI molecule can bind two trypsin units at the same time. Based on sequence and structural analysis, we hypothesize that the inherent plasticity of the β-trefoil fold is paramount in the functional evolution of this family toward multiple protease inhibition.
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Affiliation(s)
- Mohamed Azarkan
- Protein Chemistry Unit, Faculty of Medicine, Université Libre de Bruxelles, Campus Erasme (CP 609), 808 Route de Lennik, B-1070 Brussels, Belgium
| | - Sergio Martinez-Rodriguez
- Molecular Recognition Unit, Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium; Department of Molecular and Cellular Interactions, Vlaams Interuniversitair Instituut voor Biotechnologie (VIB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Lieven Buts
- Molecular Recognition Unit, Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium; Department of Molecular and Cellular Interactions, Vlaams Interuniversitair Instituut voor Biotechnologie (VIB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Danielle Baeyens-Volant
- Protein Chemistry Unit, Faculty of Medicine, Université Libre de Bruxelles, Campus Erasme (CP 609), 808 Route de Lennik, B-1070 Brussels, Belgium
| | - Abel Garcia-Pino
- Molecular Recognition Unit, Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium; Department of Molecular and Cellular Interactions, Vlaams Interuniversitair Instituut voor Biotechnologie (VIB), Pleinlaan 2, B-1050 Brussels, Belgium.
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Fragoso V, Goddard H, Baldwin IT, Kim SG. A simple and efficient micrografting method for stably transformed Nicotiana attenuata plants to examine shoot-root signaling. PLANT METHODS 2011; 7:34. [PMID: 22014154 PMCID: PMC3207920 DOI: 10.1186/1746-4811-7-34] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 10/20/2011] [Indexed: 05/18/2023]
Abstract
To adjust their development to the environment, plants rely on specific signals that travel from shoot to root and vice versa. Here we describe an efficient micrografting protocol for Nicotiana attenuata, a useful tool for identifying these signals and understanding their functions. Additionally we analyzed transcript accumulation profiles of scions and rootstocks of grafts performed with wild-type and stably transformed N. attenuata. Our results are consistent with the source-to-sink movement of an sRNA silencing signal.
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Affiliation(s)
- Variluska Fragoso
- Department of Molecular Ecology, Max-Planck-Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | | | - Ian T Baldwin
- Department of Molecular Ecology, Max-Planck-Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Sang-Gyu Kim
- Department of Molecular Ecology, Max-Planck-Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
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Stitz M, Baldwin IT, Gaquerel E. Diverting the flux of the JA pathway in Nicotiana attenuata compromises the plant's defense metabolism and fitness in nature and glasshouse. PLoS One 2011; 6:e25925. [PMID: 22022469 PMCID: PMC3189938 DOI: 10.1371/journal.pone.0025925] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 09/13/2011] [Indexed: 11/23/2022] Open
Abstract
A plant's inducible defenses against herbivores as well as certain developmental processes are known to be controlled by the jasmonic acid (JA) pathway. We have previously shown that ectopically expressing Arabidopsis thaliana JA O-methyltransferase in Nicotiana attenuata (35S-jmt) strongly reduces the herbivory-elicited jasmonate bursts by acting as metabolic sink that redirects free JA towards methylation; here we examine the consequences of this metabolic sink on N. attenuata's secondary metabolism and performance in nature. In the glasshouse, 35S-jmt plants produced fewer seed capsules due to shorter floral styles, which could be restored to wild type (WT) levels after hand-pollination, and were more susceptible to Manduca sexta larvae attack. When transplanted into the Great Basin Desert in Utah, 35S-jmt plants grew as well as WT empty vector, but were highly attacked by native herbivores of different feeding guilds: leaf chewers, miners, and single cell feeders. This greater susceptibility was strongly associated with reduced emissions of volatile organic compounds (hexenylesters, monoterpenes and sesquiterpenes) and profound alterations in the production of direct defenses (trypsin proteinase inhibitors [TPI], nicotine, diterpene glycosides [DTGs] and phenylpropanoid-polyamine conjugates) as revealed by a combination of targeted and metabolomics analyses of field collected samples. Complementation experiments with JA-Ile, whose formation is outcompeted in 35S-jmt plants by the methylation reaction, restored the local TPI activation to WT levels and partially complemented nicotine and DTG levels in elicited but not systemic leaves. These findings demonstrate that MeJA, the major JA metabolite in 35S-jmt plants, is not an active signal in defense activation and highlights the value of creating JA sinks to disrupt JA signaling, without interrupting the complete octadecanoid pathway, in order to investigate the regulation of plants' defense metabolism in nature.
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Affiliation(s)
- Michael Stitz
- Max Planck Institute for Chemical Ecology, Department of Molecular Ecology, Jena, Germany
| | - Ian T. Baldwin
- Max Planck Institute for Chemical Ecology, Department of Molecular Ecology, Jena, Germany
| | - Emmanuel Gaquerel
- Max Planck Institute for Chemical Ecology, Department of Molecular Ecology, Jena, Germany
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Gilardoni PA, Hettenhausen C, Baldwin IT, Bonaventure G. Nicotiana attenuata LECTIN RECEPTOR KINASE1 suppresses the insect-mediated inhibition of induced defense responses during Manduca sexta herbivory. THE PLANT CELL 2011; 23:3512-32. [PMID: 21926334 PMCID: PMC3203443 DOI: 10.1105/tpc.111.088229] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 08/29/2011] [Accepted: 09/05/2011] [Indexed: 05/18/2023]
Abstract
Nicotiana attenuata has the capacity to respond specifically to herbivory by its natural herbivore, Manduca sexta, through the perception of elicitors in larval oral secretions. We demonstrate that Lectin receptor kinase 1 (LecRK1) functions during M. sexta herbivory to suppress the insect-mediated inhibition of jasmonic acid (JA)-induced defense responses. Gene function analysis performed by reducing LecRK1 expression in N. attenuata by both virus-induced gene silencing and inverted repeated RNA interference (ir-lecRK1 plants) revealed that LecRK1 was essential to mount a full defense response against M. sexta folivory; larvae growing on ir-lecRK1 plants were 40 to 100% larger than those growing on wild-type plants. The insect-induced accumulation of nicotine, diterpene-glucosides, and trypsin protease inhibitors, as well as the expression of Thr deaminase, was severalfold reduced in ir-lecRK1 plants compared with the wild type. The accumulation of JA and JA-Ile was unaffected during herbivory in ir-lecRK1 plants; however, salicylic acid (SA) accumulation was increased by twofold. The expression of nahG in ir-lecRK1 plants prevented the increased accumulation of SA and restored the defense response against M. sexta herbivory. The results suggest that LecRK1 inhibits the accumulation of SA during herbivory, although other mechanisms may also be affected.
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Affiliation(s)
| | | | | | - Gustavo Bonaventure
- Department of Molecular Ecology, Max Planck Institute of Chemical Ecology, D-07745 Jena, Germany
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79
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Heinrich M, Baldwin IT, Wu J. Two mitogen-activated protein kinase kinases, MKK1 and MEK2, are involved in wounding- and specialist lepidopteran herbivore Manduca sexta-induced responses in Nicotiana attenuata. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:4355-65. [PMID: 21610019 PMCID: PMC3153688 DOI: 10.1093/jxb/err162] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 04/14/2011] [Accepted: 04/25/2011] [Indexed: 05/18/2023]
Abstract
In a wild tobacco plant, Nicotiana attenuata, two mitogen-activated protein kinases (MAPKs), salicylic acid-induced protein kinase (SIPK) and wound-induced protein kinase (WIPK), play central roles in modulating herbivory-induced phytohormone and anti-herbivore secondary metabolites. However, the identities of their upstream MAPK kinases (MAPKKs) were elusive. Ectopic overexpression studies in N. benthamiana and N. tabacum suggested that two MAPKKs, MKK1 and MEK2, may activate SIPK and WIPK. The homologues of MKK1 and MEK2 were cloned in N. attenuata (NaMKK1 and NaMEK2) and a virus-induced gene silencing approach was used to knock-down the transcript levels of these MAPKK genes. Plants silenced in NaMKK1 and NaMEK2 were treated with wounding or simulated herbivory by applying the oral secretions of the specialist herbivore Manduca sexta to wounds. MAPK activity assay indicated that after wounding or simulated herbivory NaMKK1 is not required for the phosphorylation of NaSIPK and NaWIPK; in contrast, NaMEK2 and other unknown MAPKKs are important for simulated herbivory-elicited activation of NaSIPK and NaWIPK, and after wounding NaMEK2 probably does not activate NaWIPK but plays a minor role in activating NaSIPK. Consistently, NaMEK2 and certain other MAPKKs, but not NaMKK1, are needed for wounding- and simulated herbivory-elicited accumulation of jasmonic acid (JA), JA-isoleucine, and ethylene. Furthermore, both NaMEK2 and NaMKK1 regulate the levels of trypsin proteinase inhibitors. The findings underscore the complexity of MAPK signalling pathways and highlight the importance of MAPKKs in regulating wounding- and herbivory-induced responses.
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Affiliation(s)
| | | | - Jianqiang Wu
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll Str. 8, D-07745 Jena, Germany
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80
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Wünsche H, Baldwin IT, Wu J. S-Nitrosoglutathione reductase (GSNOR) mediates the biosynthesis of jasmonic acid and ethylene induced by feeding of the insect herbivore Manduca sexta and is important for jasmonate-elicited responses in Nicotiana attenuata. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:4605-16. [PMID: 21622839 PMCID: PMC3170554 DOI: 10.1093/jxb/err171] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 04/20/2011] [Accepted: 05/04/2011] [Indexed: 05/17/2023]
Abstract
S-nitrosoglutathione reductase (GSNOR) reduces the nitric oxide (NO) adduct S-nitrosoglutathione (GSNO), an essential reservoir for NO bioactivity. In plants, GSNOR has been found to be important in resistance to bacterial and fungal pathogens, but whether it is also involved in plant-herbivore interactions was not known. Using a virus-induced gene silencing (VIGS) system, the activity of GSNOR in a wild tobacco species, Nicotiana attenuata, was knocked down and the function of GSNOR in defence against the insect herbivore Manduca sexta was examined. Silencing GSNOR decreased the herbivory-induced accumulation of jasmonic acid (JA) and ethylene, two important phytohormones regulating plant defence levels, without compromising the activity of two mitogen-activated protein kinases (MAPKs), salicylic acid-induced protein kinase (SIPK) and wound-induced protein kinase (WIPK). Decreased activity of trypsin proteinase inhibitors (TPIs) were detected in GSNOR-silenced plants after simulated M. sexta feeding and bioassays indicated that GSNOR-silenced plants have elevated susceptibility to M. sexta attack. Furthermore, GSNOR is required for methyl jasmonate (MeJA)-induced accumulation of defence-related secondary metabolites (TPI, caffeoylputrescine, and diterpene glycosides) but is not needed for the transcriptional regulation of JAZ3 (jasmonate ZIM-domain 3) and TD (threonine deaminase), indicating that GSNOR mediates certain but not all jasmonate-inducible responses. This work highlights the important role of GSNOR in plant resistance to herbivory and jasmonate signalling and suggests the potential involvement of NO in plant-herbivore interactions. Our data also suggest that GSNOR could be a target of genetic modification for improving crop resistance to herbivores.
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Affiliation(s)
| | | | - Jianqiang Wu
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, D-07745 Jena, Germany
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81
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Fujimoto T, Tomitaka Y, Abe H, Tsuda S, Futai K, Mizukubo T. Expression profile of jasmonic acid-induced genes and the induced resistance against the root-knot nematode (Meloidogyne incognita) in tomato plants (Solanum lycopersicum) after foliar treatment with methyl jasmonate. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:1084-97. [PMID: 21216026 DOI: 10.1016/j.jplph.2010.12.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 12/04/2010] [Accepted: 12/05/2010] [Indexed: 05/18/2023]
Abstract
We investigated what gene(s) in the plant roots have the positive role against repressing root-knot nematode (RKN) infection. We investigated the interaction between RKN infection and gene expression in the plant roots induced by methyl jasmonate (MeJA). We focused on the induced resistance response and the duration after foliar treatment with MeJA of 0.1, 0.5, 1.0, and 5.0mM at 1, 24, 48, and 72h prior to the inoculation of RKN. As a result, the foliar treatment with MeJA at 0.5mM or higher concentrations significantly reduced the infection of RKN in plants and the effect lasted for about 1 week. The repressing effect on RKN population declined to the lowest level in two weeks after MeJA treatment. The expression of proteinase inhibitors (PIs) and multicystatin (MC) were induced while the repressing effect on RKN was valid and a negative correlation was found between the expression of PIs or MC and RKN infection. In addition, when tomato plants no longer expressing MC and PIs were treated again with MeJA, the repressing effect revived. These phenomena appeared to be regardless of the existence of Mi-genes or isolate of RKN. Our results indicate that the expression level of MC and PIs may be effective as marker genes for estimating the induced resistance response against RKN infection.
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Affiliation(s)
- Taketo Fujimoto
- Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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82
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Franzke A, Reinhold K. Stressing food plants by altering water availability affects grasshopper performance. Ecosphere 2011. [DOI: 10.1890/es11-00095.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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83
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Maserti BE, Del Carratore R, Croce CMD, Podda A, Migheli Q, Froelicher Y, Luro F, Morillon R, Ollitrault P, Talon M, Rossignol M. Comparative analysis of proteome changes induced by the two spotted spider mite Tetranychus urticae and methyl jasmonate in citrus leaves. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:392-402. [PMID: 20926159 DOI: 10.1016/j.jplph.2010.07.026] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 07/29/2010] [Accepted: 07/30/2010] [Indexed: 05/24/2023]
Abstract
Citrus plants are currently facing biotic and abiotic stresses. Therefore, the characterization of molecular traits involved in the response mechanisms to stress could facilitate selection of resistant varieties. Although large cDNA microarray profiling has been generated in citrus tissues, the available protein expression data are scarce. In this study, to identify differentially expressed proteins in Citrus clementina leaves after infestation by the two-spotted spider mite Tetranychus urticae, a proteome comparison was undertaken using two-dimensional gel electrophoresis. The citrus leaf proteome profile was also compared with that of leaves treated over 0-72h with methyl jasmonate, a compound playing a key role in the defense mechanisms of plants to insect/arthropod attack. Significant variations were observed for 110 protein spots after spider mite infestation and 67 protein spots after MeJA treatments. Of these, 50 proteins were successfully identified by liquid chromatography-mass spectrometry-tandem mass spectrometry. The majority constituted photosynthesis- and metabolism-related proteins. Five were oxidative stress associated enzymes, including phospholipid glutathione peroxidase, a salt stressed associated protein, ascorbate peroxidase and Mn-superoxide dismutase. Seven were defense-related proteins, such as the pathogenesis-related acidic chitinase, the protease inhibitor miraculin-like protein, and a lectin-like protein. This is the first report of differentially regulated proteins after T. urticae attack and exogenous MeJA application in citrus leaves.
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Affiliation(s)
- B E Maserti
- CNR-IBF, Istituto di BioFisica, Area della Ricerca, Via Moruzzi 1, Pisa, Italy
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84
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Meldau S, Baldwin IT, Wu J. SGT1 regulates wounding- and herbivory-induced jasmonic acid accumulation and Nicotiana attenuata's resistance to the specialist lepidopteran herbivore Manduca sexta. THE NEW PHYTOLOGIST 2011; 189:1143-1156. [PMID: 21118264 DOI: 10.1111/j.1469-8137.2010.03558.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
• SGT1 (suppressor of G-two allele of SKP1) is a conserved protein in all eukaryotes and is crucial for resisting pathogens in humans and plants. We studied whether SGT1 is involved in the induced defense response of a native tobacco (Nicotiana attenuata) to its natural herbivore, Manduca sexta. • We diminished NaSGT1 transcription in N. attenuata using virus-induced gene silencing (VIGS) and analysed the induced defense responses after wounding and M. sexta elicitation. • Silencing NaSGT1 highly attenuates wounding- and herbivory-induced amounts of jasmonic acid (JA) and JA-isoleucine but elevates the concentration of salicylic acid. Chemical profiling reveals that NaSGT1-silenced plants are also compromised in their ability to accumulate JA precursors produced in chloroplasts. We show that the reduced JA accumulation in NaSGT1-silenced plants is independent of the elevated salicylic acid levels. NaSGT1-silenced plants have decreased contents of defensive metabolites and have compromised resistance to M. sexta larvae. Transcript analyses after methyl jasmonate (MeJA) treatment revealed that NaSGT1 is important for the normal regulation of MeJA-induced transcriptional responses. • This work demonstrates the importance of SGT1 in the regulatory network that deploys defense responses against herbivores, and highlights the significance of SGT1 in plants' responses to JA.
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Affiliation(s)
- Stefan Meldau
- Max Planck Institute for Chemical Ecology, Hans-Knöll Straße 8, D-07745 Jena, Germany
| | - Ian T Baldwin
- Max Planck Institute for Chemical Ecology, Hans-Knöll Straße 8, D-07745 Jena, Germany
| | - Jianqiang Wu
- Max Planck Institute for Chemical Ecology, Hans-Knöll Straße 8, D-07745 Jena, Germany
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85
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Yang DH, Hettenhausen C, Baldwin IT, Wu J. BAK1 regulates the accumulation of jasmonic acid and the levels of trypsin proteinase inhibitors in Nicotiana attenuata's responses to herbivory. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:641-52. [PMID: 20937731 PMCID: PMC3003809 DOI: 10.1093/jxb/erq298] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 08/30/2010] [Accepted: 09/03/2010] [Indexed: 05/18/2023]
Abstract
BAK1 is a co-receptor of brassinosteroid (BR) receptor BRI1, and plays a well-characterized role in BR signalling. BAK1 also physically interacts with the flagellin receptor FLS2 and regulates pathogen resistance. The role of BAK1 in mediating Nicotiana attenuata's resistance responses to its specialist herbivore, Manduca sexta, was examined here. A virus-induced gene-silencing system was used to generate empty vector (EV) and NaBAK1-silenced plants. The wounding- and herbivory-induced responses were examined on EV and NaBAK1-silenced plants by wounding plants or simulating herbivory by treating wounds with larval oral secretions (OS). After wounding or OS elicitation, NaBAK1-silenced plants showed attenuated jasmonic acid (JA) and JA-isoleucine bursts, phytohormone responses important in mediating plant defences against herbivores. However, these decreased JA and JA-Ile levels did not result from compromised MAPK activity or elevated SA levels. After simulated herbivory, NaBAK1-silenced plants had EV levels of defensive secondary metabolites, namely, trypsin proteinase inhibitors (TPIs), and similar levels of resistance to Manduca sexta larvae. Additional experiments demonstrated that decreased JA levels in NaBAK1-VIGS plants, rather than the enzymatic activity of JAR proteins or Ile levels, were responsible for the reduced JA-Ile levels observed in these plants. Methyl jasmonate application elicited higher levels of TPI activity in NaBAK1-silenced plants than in EV plants, suggesting that silencing NaBAK1 enhances the accumulation of TPIs induced by a given level of JA. Thus NaBAK1 is involved in modulating herbivory-induced JA accumulation and how JA levels are transduced into TPI levels in N. attenuata.
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Affiliation(s)
| | | | | | - Jianqiang Wu
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll Straße 8, D-07745 Jena, Germany
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86
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Chen Y, Whitehill JGA, Bonello P, Poland TM. Differential response in foliar chemistry of three ash species to emerald ash borer adult feeding. J Chem Ecol 2010; 37:29-39. [PMID: 21153046 DOI: 10.1007/s10886-010-9892-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 11/11/2010] [Accepted: 11/29/2010] [Indexed: 11/29/2022]
Abstract
The emerald ash borer (EAB; Agrilus planipennis Fairmaire; Coleoptera: Buprestidae), is an exotic wood-boring beetle that has been threatening North American ash (Fraxinus spp.) resources since its discovery in Michigan and Ontario in 2002. In this study, we investigated the phytochemical responses of the three most common North American ash species (black, green, and white ash) in northeastern USA to EAB adult feeding. Black ash was the least responsive to EAB adult feeding in terms of the induction of volatile compounds, and levels of only two (indole and benzyl cyanide) of the 11 compounds studied increased. In green ash, levels of two [(E)-β-ocimene and indole] of the 11 volatile compounds studied were elevated, while the levels of two green leaf volatiles [hexanal and (E)-2-hexenal] decreased. White ash showed the greatest response with an increase in levels of seven of the 11 compounds studied. Qualitative differences among ash species were detected. Among the phenolic compounds detected, ligustroside was the only one detected in all three species. Oleuropein aglycone and 2 unidentified compounds were found only in black ash; coumaroylquinic acid and feruloylquinic acid were detected only in green ash; and verbascoside hexoside was detected only in white ash. EAB adult feeding did not elicit or decrease concentrations of any selected individual phenolic compounds. However, although levels of total phenolics from black and green ash foliage were not affected by EAB adult feeding, they decreased significantly in white ash. EAB adult feeding elevated chymotrypsin inhibitors in black ash. The possible ecological implications of these findings are discussed.
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Affiliation(s)
- Yigen Chen
- Department of Entomology, Michigan State University, East Lansing, MI 48824, USA.
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87
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Hartl M, Giri AP, Kaur H, Baldwin IT. Serine protease inhibitors specifically defend Solanum nigrum against generalist herbivores but do not influence plant growth and development. THE PLANT CELL 2010; 22:4158-75. [PMID: 21177479 PMCID: PMC3027172 DOI: 10.1105/tpc.109.073395] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 11/15/2010] [Accepted: 12/01/2010] [Indexed: 05/18/2023]
Abstract
Solanaceaeous taxa produce diverse peptide serine proteinase inhibitors (SPIs), known antidigestive defenses that might also control endogenous plant proteases. If and how a plant coordinates and combines its different SPIs for the defense against herbivores and if these SPIs simultaneously serve developmental functions is unknown. We examine Solanum nigrum's SPI profile, comprising four different active inhibitors, of which the most abundant proved to be novel, to understand their functional specialization in an ecological context. Transcript and activity characterization revealed tissue-specific and insect-elicited accumulation patterns. Stable and transient gene silencing of all four SPIs revealed different specificities for target proteinases: the novel SPI2c displayed high specificity for trypsin and chymotrypsin, while two other SPI2 homologs were highly active against subtilisin. In field and lab experiments, we found all four SPIs to display herbivore- and gene-specific defensive properties, with dissimilar effects on closely related species. However, we did not observe any clear developmental phenotype in SPI-silenced plants, suggesting that SPIs do not play a major role in regulating endogenous proteases under the conditions studied. In summary, specific single SPIs or their combinations defend S. nigrum against generalist herbivores, while the defense against herbivores specialized on SPI-rich diets requires other unknown defense mechanisms.
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Affiliation(s)
- Markus Hartl
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany.
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88
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Oliva MLV, Silva MC, Sallai RC, Brito MV, Sampaio MU. A novel subclassification for Kunitz proteinase inhibitors from leguminous seeds. Biochimie 2010; 92:1667-73. [DOI: 10.1016/j.biochi.2010.03.021] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 03/26/2010] [Indexed: 11/16/2022]
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89
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Onkokesung N, Baldwin IT, Gális I. The role of jasmonic acid and ethylene crosstalk in direct defense of Nicotiana attenuata plants against chewing herbivores. PLANT SIGNALING & BEHAVIOR 2010; 5:1305-7. [PMID: 20930539 PMCID: PMC3115374 DOI: 10.4161/psb.5.10.13124] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 07/23/2010] [Indexed: 05/20/2023]
Abstract
We examined performance of herbivores on plants lacking either jasmonate (JA, asLOX3) or ethylene (ET, mETR1) signaling, or both (mETR1asLOX3). Plant defenses against Manduca sexta caterpillars were strongly impaired in JA-deficient asLOX3 plants; however, making asLOX3 plants ethylene insensitive did not further increase the performance of the larvae on a mETR1asLOX3 genetic cross. This result demonstrates the dominant role of JA over ET in the regulation of plant defenses against herbivores. However, ET-insensitivity combined with otherwise normal levels of JA in mETR1 plants promoted faster caterpillar growth, which correlated with reduced accumulation of the alkaloidal direct defense nicotine in mETR1 compared to WT plants. Our data points to an important accessory function of ET in the activation of JA-regulated plant defenses against herbivores at the level of alkaloid biosynthesis in the roots and/or accumulation in the leaves.
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Affiliation(s)
- Nawaporn Onkokesung
- Max Planck Institute for Chemical Ecology, Department of Molecular Ecology, Jena, Germany
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90
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Huang H, Qi SD, Qi F, Wu CA, Yang GD, Zheng CC. NtKTI1, a Kunitz trypsin inhibitor with antifungal activity from Nicotiana tabacum, plays an important role in tobacco's defense response. FEBS J 2010; 277:4076-88. [PMID: 20735473 DOI: 10.1111/j.1742-4658.2010.07803.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A cDNA library from tobacco inoculated with Rhizoctonia solani was constructed, and several cDNA fragments were identified by differential hybridization screening. One cDNA clone that was dramatically repressed, NtKTI1, was confirmed as a member of the Kunitz plant proteinase inhibitor family. RT-PCR analysis revealed that NtKTI1 was constitutively expressed throughout the whole plant and preferentially expressed in the roots and stems. Furthermore, RT-PCR analysis showed that NtKTI1 expression was repressed after R. solani inoculation, mechanical wounding and salicylic acid treatment, but was unaffected by methyl jasmonate, abscisic acid and NaCl treatment. In vitro assays showed that NtKTI1 exerted prominent antifungal activity towards R. solani and moderate antifungal activity against Rhizopus nigricans and Phytophthora parasitica var. nicotianae. Bioassays of transgenic tobacco demonstrated that overexpression of NtKTI1 enhanced significantly the resistance of tobacco against R. solani, and the antisense lines exhibited higher susceptibility than control lines towards the phytopathogen. Taken together, these studies suggest that NtKTI1 may be a functional Kunitz trypsin inhibitor with antifungal activity against several important phytopathogens in the tobacco defense response.
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Affiliation(s)
- Hao Huang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, China
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91
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Anderson JT, Mitchell-Olds T. Ecological genetics and genomics of plant defenses: Evidence and approaches. Funct Ecol 2010; 25:312-324. [PMID: 21532968 DOI: 10.1111/j.1365-2435.2010.01785.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Herbivores exert significant selection on plants, and plants have evolved a variety of constitutive and inducible defenses to resist and tolerate herbivory. Assessing the genetic mechanisms that influence defenses against herbivores will deepen our understanding of the evolution of essential phenotypic traits.Ecogenomics is a powerful interdisciplinary approach that can address fundamental questions about the ecology and evolutionary biology of species, such as: which evolutionary forces maintain variation within a population? and What is the genetic architecture of adaptation? This field seeks to identify gene regions that influence ecologically-important traits, assess the fitness consequences under natural conditions of alleles at key quantitative trait loci (QTLs), and test how the abiotic and biotic environment affects gene expression.Here, we review ecogenomics techniques and emphasize how this framework can address long-standing and emerging questions relating to anti-herbivore defenses in plants. For example, ecogenomics tools can be used to investigate: inducible vs. constitutive defenses; tradeoffs between resistance and tolerance; adaptation to the local herbivore community; selection on alleles that confer resistance and tolerance in natural populations; and whether different genes are activated in response to specialist vs. generalist herbivores and to different types of damage.Ecogenomic studies can be conducted with model species, such as Arabidopsis, or their relatives, in which case myriad molecular tools are already available. Burgeoning sequence data will also facilitate ecogenomic studies of non-model species. Throughout this paper, we highlight approaches that are particularly suitable for ecological studies of non-model organisms, discuss the benefits and disadvantages of specific techniques, and review bioinformatic tools for analyzing data.We focus on established and promising techniques, such as QTL mapping with pedigreed populations, genome wide association studies, transcription profiling strategies, population genomics, and transgenic methodologies. Many of these techniques are complementary and can be used jointly to investigate the genetic architecture of defense traits and selection on alleles in nature.
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Affiliation(s)
- Jill T Anderson
- Institute for Genome Sciences and Policy, Department of Biology, Duke University, P.O. Box 90338, Durham, North Carolina 27708, USA
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92
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Jassbi AR, Zamanizadehnajari S, Baldwin IT. 17-Hydroxygeranyllinalool glycosides are major resistance traits of Nicotiana obtusifolia against attack from tobacco hornworm larvae. PHYTOCHEMISTRY 2010; 71:1115-21. [PMID: 20452633 DOI: 10.1016/j.phytochem.2010.04.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2010] [Revised: 04/12/2010] [Accepted: 04/13/2010] [Indexed: 05/08/2023]
Abstract
In the Great Basin Desert, Nicotiana obtusifolia (synonymous with Nicotiana trigonophylla) and Nicotiana attenuata co-occur, but the former is frequently less attacked by larvae of the tobacco hornworm than the latter, despite having lower nicotine and trypsin protease inhibitor defenses. Glycosides of the diterpene, 17-hydroxygeranyllinalool (HGL-DTGs) have recently been found to be important defenses of N. attenuata. Total HGL-DTG levels are 5-fold higher in N. obtusifolia than in N. attenuata, and we characterize the three major HGL-DTGs purified from N. obtusifolia leaves as: 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-17-hydroxygeranyllinalool-17-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranoside; nicotinoside III and its malonic acid conjugates. Using APCI- and ESI-LC-MS, we also identified mono- and diacetyl-nicotinoside III and quercetin glycosides. To evaluate the defensive value of these HGL-DTGs, we used virus-induced-gene silencing to reduce the transcript levels of geranylgeranyl diphosphate synthase and total HGL-DTG levels in both species. When fed on silenced plants, larvae gained up to about two times more mass than those that fed on empty vector control plants of both species. We conclude that HGL-DTGs function as the most important direct defenses for both N. attenuata and N. obtusifolia.
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Affiliation(s)
- Amir Reza Jassbi
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, D-07745 Jena, Germany
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93
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Onkokesung N, Gális I, von Dahl CC, Matsuoka K, Saluz HP, Baldwin IT. Jasmonic acid and ethylene modulate local responses to wounding and simulated herbivory in Nicotiana attenuata leaves. PLANT PHYSIOLOGY 2010; 153:785-98. [PMID: 20382894 PMCID: PMC2879812 DOI: 10.1104/pp.110.156232] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Accepted: 04/06/2010] [Indexed: 05/19/2023]
Abstract
Jasmonic acid (JA) and ethylene (ET) are known to play important roles in mediating plant defense against herbivores, but how they affect development in herbivore-attacked plants is unknown. We used JA-deficient (silenced in LIPOXYGENASE3 [asLOX3]) and ET-insensitive (expressing a mutated dominant negative form of ETHYLENE RESPONSE1 [mETR1]) Nicotiana attenuata plants, and their genetic cross (mETR1asLOX3), to examine growth and development of these plants under simulated herbivory conditions. At the whole plant level, both hormones suppressed leaf expansion after the plants had been wounded and the wounds had been immediately treated with Manduca sexta oral secretions (OS). In addition, ectopic cell expansion was observed around both water- and OS-treated wounds in mETR1asLOX3 leaves but not in mETR1, asLOX3, or wild-type leaves. Pretreating asLOX3 leaves with the ET receptor antagonist 1-methylcyclopropane resulted in local cell expansion that closely mimicked the mETR1asLOX3 phenotype. We found higher auxin (indole-3-acetic acid) levels in the elicited leaves of mETR1asLOX3 plants, a trait that is putatively associated with enhanced cell expansion and leaf growth in this genotype. Transcript profiling of OS-elicited mETR1asLOX3 leaves revealed a preferential accumulation of transcripts known to function in cell wall remodeling, suggesting that both JA and ET act as negative regulators of these genes. We propose that in N. attenuata, JA-ET cross talk restrains local cell expansion and growth after herbivore attack, allowing more resources to be allocated to induced defenses against herbivores.
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Affiliation(s)
| | - Ivan Gális
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany (N.O., I.G., C.C.v.D., I.T.B.); Faculty of Agriculture, Kyushu University, 812–8581 Fukuoka, Japan (K.M.); Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, 07745 Jena, Germany (H.-P.S.)
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94
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Gilardoni PA, Schuck S, Jüngling R, Rotter B, Baldwin IT, Bonaventure G. SuperSAGE analysis of the Nicotiana attenuata transcriptome after fatty acid-amino acid elicitation (FAC): identification of early mediators of insect responses. BMC PLANT BIOLOGY 2010; 10:66. [PMID: 20398280 PMCID: PMC3095340 DOI: 10.1186/1471-2229-10-66] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 04/14/2010] [Indexed: 05/19/2023]
Abstract
BACKGROUND Plants trigger and tailor defense responses after perception of the oral secretions (OS) of attacking specialist lepidopteran larvae. Fatty acid-amino acid conjugates (FACs) in the OS of the Manduca sexta larvae are necessary and sufficient to elicit the herbivory-specific responses in Nicotiana attenuata, an annual wild tobacco species. How FACs are perceived and activate signal transduction mechanisms is unknown. RESULTS We used SuperSAGE combined with 454 sequencing to quantify the early transcriptional changes elicited by the FAC N-linolenoyl-glutamic acid (18:3-Glu) and virus induced gene silencing (VIGS) to examine the function of candidate genes in the M. sexta-N. attenuata interaction. The analysis targeted mRNAs encoding regulatory components: rare transcripts with very rapid FAC-elicited kinetics (increases within 60 and declines within 120 min). From 12,744 unique Tag sequences identified (UniTags), 430 and 117 were significantly up- and down-regulated >or= 2.5-fold, respectively, after 18:3-Glu elicitation compared to wounding. Based on gene ontology classification, more than 25% of the annotated UniTags corresponded to putative regulatory components, including 30 transcriptional regulators and 22 protein kinases. Quantitative PCR analysis was used to analyze the FAC-dependent regulation of a subset of 27 of these UniTags and for most of them a rapid and transient induction was confirmed. Six FAC-regulated genes were functionally characterized by VIGS and two, a putative lipid phosphate phosphatase (LPP) and a protein of unknown function, were identified as important mediators of the M. sexta-N. attenuata interaction. CONCLUSIONS The analysis of the early changes in the transcriptome of N. attenuata after FAC elicitation using SuperSAGE/454 has identified regulatory genes involved in insect-specific mediated responses in plants. Moreover, it has provided a foundation for the identification of additional novel regulators associated with this process.
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Affiliation(s)
- Paola A Gilardoni
- Max Planck Institute for Chemical Ecology, Department of Molecular Ecology, Hans Knöll Str. 8, 07745 Jena, Germany
| | - Stefan Schuck
- Max Planck Institute for Chemical Ecology, Department of Molecular Ecology, Hans Knöll Str. 8, 07745 Jena, Germany
| | - Ruth Jüngling
- GenXPro GmbH, Altenhöferallee 3, 60438 Frankfurt am Main, Germany
| | - Björn Rotter
- GenXPro GmbH, Altenhöferallee 3, 60438 Frankfurt am Main, Germany
| | - Ian T Baldwin
- Max Planck Institute for Chemical Ecology, Department of Molecular Ecology, Hans Knöll Str. 8, 07745 Jena, Germany
| | - Gustavo Bonaventure
- Max Planck Institute for Chemical Ecology, Department of Molecular Ecology, Hans Knöll Str. 8, 07745 Jena, Germany
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95
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Bezzi S, Kessler D, Diezel C, Muck A, Anssour S, Baldwin IT. Silencing NaTPI expression increases nectar germin, nectarins, and hydrogen peroxide levels and inhibits nectar removal from plants in nature. PLANT PHYSIOLOGY 2010; 152:2232-42. [PMID: 20190094 PMCID: PMC2850041 DOI: 10.1104/pp.109.151753] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2009] [Accepted: 02/24/2010] [Indexed: 05/21/2023]
Abstract
Native flower visitors removed less nectar from trypsin proteinase inhibitor (TPI)-silenced Nicotiana attenuata plants (ir-pi) than from wild-type plants in four field seasons of releases, even when the nectar repellent, nicotine, was also silenced. Analysis of floral chemistry revealed no differences in the emission of the floral attractants benzylacetone and benzaldehyde or in the concentrations of nectar sugar and nicotine between wild-type and ir-pi flowers, suggesting that these two lines are equally able to attract insect visitors. TPI activity was found in all wild-type flower parts and was highest in anther heads, while TPI activity was not found in any parts of ir-pi flowers. The nectar of ir-pi flowers contained 3.6-fold more total proteins than the nectar of wild-type flowers. Proteomics analysis and hydrogen peroxide (H2O2) measurements revealed that ir-pi nectar contained more nectarins and nectar germin-like proteins and about 1.5-fold more H2O2 compared with wild-type nectar. Field experiments with wild-type flowers supplemented with a solution containing sugar and glucose oxidase demonstrated a causal association between the accumulation of H2O2 and the reduction in nectar removal. These results showed that silencing TPI expression increases the accumulation of nectar proteins and H2O2 levels, which in turn reduces nectar removal by native insect floral visitors. The effect of silencing TPIs on nectar protein accumulation suggests an endogenous regulatory function for TPIs in N. attenuata flowers. The repellency of H2O2 to floral visitors raises new questions about the qualities of nectar that make it attractive for pollinators.
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96
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Kaplan I, Thaler JS. Plant resistance attenuates the consumptive and non-consumptive impacts of predators on prey. OIKOS 2010. [DOI: 10.1111/j.1600-0706.2009.18311.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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97
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Kessler D, Diezel C, Baldwin IT. Changing Pollinators as a Means of Escaping Herbivores. Curr Biol 2010; 20:237-42. [DOI: 10.1016/j.cub.2009.11.071] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 11/21/2009] [Accepted: 11/25/2009] [Indexed: 10/19/2022]
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98
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Ma QH, Tian B, Li YL. Overexpression of a wheat jasmonate-regulated lectin increases pathogen resistance. Biochimie 2010; 92:187-93. [PMID: 19958808 PMCID: PMC7117000 DOI: 10.1016/j.biochi.2009.11.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 11/24/2009] [Indexed: 01/22/2023]
Abstract
Jasmonates are known to induce the transcriptional activation of plant defense genes, which leads to the production of jasmonate-regulated proteins (JRP). We previously cloned and characterized a novel jacalin-like lectin gene (Ta-JA1) from wheat (Triticum aestivum L.), which codes a modular JRP with disease response and jacalin-related lectin (JRL) domains and is present only in the Gramineae family. The function of this protein is still unclear. Phylogenetic analysis indicated that Ta-JA1 and related proteins from cereals grouped together, which diverged from JRL with an additional N-terminal disease response domain. The recombinant Ta-JA1 proteins agglutinated rabbit erythrocytes, and this hemagglutination activity was preferentially inhibited by mannose. The Ta-JA1 protein was able to inhibit E. coli cell growth. Overexpression of Ta-JA1 in transgenic tobacco plants increased their resistance to infection by tobacco bacterial, fungal and viral pathogens. Our results suggest that Ta-JA1 belongs to a mannose-specific lectin, which may confer a basal but broad-spectrum resistance to plant pathogens. Ta-JA1 and its homologues in maize, rice, sorghum and creeping bentgrass may represent a new type of monocot lectin with a modular structure and diversity of physiological functions in biotic and abiotic stress responses.
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Affiliation(s)
- Qing-Hu Ma
- Institute of Botany, Chinese Academy of Sciences, Beijing, China.
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99
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Demkura PV, Abdala G, Baldwin IT, Ballaré CL. Jasmonate-dependent and -independent pathways mediate specific effects of solar ultraviolet B radiation on leaf phenolics and antiherbivore defense. PLANT PHYSIOLOGY 2010; 152:1084-95. [PMID: 20007446 PMCID: PMC2815854 DOI: 10.1104/pp.109.148999] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2009] [Accepted: 12/07/2009] [Indexed: 05/18/2023]
Abstract
Ultraviolet B (UV-B) radiation, a very small fraction of the daylight spectrum, elicits changes in plant secondary metabolism that have large effects on plant-insect interactions. The signal transduction pathways that mediate these specific effects of solar UV-B are not known. We examined the role of jasmonate signaling by measuring responses to UV-B in wild-type and transgenic jasmonate-deficient Nicotiana attenuata plants in which a lipoxygenase gene (NaLOX3) was silenced (as-lox). In wild-type plants, UV-B failed to elicit the accumulation of jasmonic acid (JA) or the bioactive JA-isoleucine conjugate but amplified the response of jasmonate-inducible genes, such as trypsin proteinase inhibitor (TPI), to wounding and methyl jasmonate, and increased the accumulation of several phenylpropanoid derivatives. Some of these phenolic responses (accumulation of caffeoyl-polyamine conjugates) were completely lacking in as-lox plants, whereas others (accumulation of rutin and chlorogenic acid) were similar in both genotypes. In open field conditions, as-lox plants received more insect damage than wild-type plants, as expected, but the dramatic increase in resistance to herbivory elicited by UV-B exposure, which was highly significant in wild-type plants, did not occur in as-lox plants. We conclude that solar UV-B (1) uses jasmonate-dependent and -independent pathways in the elicitation of phenolic compounds, and (2) increases sensitivity to jasmonates, leading to enhanced expression of wound-response genes (TPI). The lack of UV-B-induced antiherbivore protection in as-lox plants suggests that jasmonate signaling plays a central role in the mechanisms by which solar UV-B increases resistance to insect herbivores in the field.
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Affiliation(s)
| | | | | | - Carlos L. Ballaré
- Instituto de Investigaciones Fisiológicas y Ecológicas vinculadas a la Agricultura, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, C1417DSE Buenos Aires, Argentina (P.V.D., C.L.B.); Departamento de Ciencias Naturales, Facultad de Ciencias Exactas Fisicoquímicas y Naturales, Universidad Nacional de Río Cuarto, 5800 Río Cuarto, Argentina (G.A.); and Department of Molecular Ecology, Max-Planck-Institute for Chemical Ecology, 07745 Jena, Germany (I.T.B.)
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100
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Govind G, Mittapalli O, Griebel T, Allmann S, Böcker S, Baldwin IT. Unbiased transcriptional comparisons of generalist and specialist herbivores feeding on progressively defenseless Nicotiana attenuata plants. PLoS One 2010; 5:e8735. [PMID: 20090945 PMCID: PMC2806910 DOI: 10.1371/journal.pone.0008735] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 12/20/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Herbivore feeding elicits dramatic increases in defenses, most of which require jasmonate (JA) signaling, and against which specialist herbivores are thought to be better adapted than generalist herbivores. Unbiased transcriptional analyses of how neonate larvae cope with these induced plant defenses are lacking. METHODOLOGY/PRINCIPAL FINDINGS We created cDNA microarrays for Manduca sexta and Heliothis virescens separately, by spotting normalized midgut-specific cDNA libraries created from larvae that fed for 24 hours on MeJA-elicited wild-type (WT) Nicotiana attenuata plants. These microarrays were hybridized with labeled probes from neonates that fed for 24 hours on WT and isogenic plants progressively silenced in JA-mediated defenses (N: nicotine; N/PI: N and trypsin protease inhibitors; JA: all JA-mediated defenses). H. virescens neonates regulated 16 times more genes than did M. sexta neonates when they fed on plants silenced in JA-mediated defenses, and for both species, the greater the number of defenses silenced in the host plant (JA > N/PI > N), the greater were the number of transcripts regulated in the larvae. M. sexta larvae tended to down-regulate while H. virescens larvae up- and down-regulated transcripts from the same functional categories of genes. M. sexta larvae regulated transcripts in a diet-specific manner, while H. virescens larvae regulated a similar suite of transcripts across all diet types. CONCLUSIONS/SIGNIFICANCE The observations are consistent with the expectation that specialists are better adapted than generalist herbivores to the defense responses elicited in their host plants by their feeding. While M. sexta larvae appear to be better adapted to N. attenuata's defenses, some of the elicited responses remain effective defenses against both herbivore species. The regulated genes provide novel insights into larval adaptations to N. attenuata's induced defenses, and represent potential targets for plant-mediated RNAi to falsify hypotheses about the process of adaptation.
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Affiliation(s)
- Geetha Govind
- Max Planck Institute for Chemical Ecology, Jena, Germany
| | | | - Thasso Griebel
- Faculty of Mathematics and Computer Science, Friedrich Schiller University of Jena, Jena, Germany
| | - Silke Allmann
- Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Sebastian Böcker
- Faculty of Mathematics and Computer Science, Friedrich Schiller University of Jena, Jena, Germany
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