151
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Gill TA, Sandoya G, Williams P, Luthe DS. Belowground resistance to western corn rootworm in lepidopteran-resistant maize genotypes. JOURNAL OF ECONOMIC ENTOMOLOGY 2011; 104:299-307. [PMID: 21404871 DOI: 10.1603/ec10117] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Several maize, Zea mays L., inbred lines developed from an Antiguan maize population have been shown to exhibit resistance to numerous aboveground lepidopteran pests. This study shows that these genotypes are able to significantly reduce the survival of two root feeding pests, western corn rootworm, Diabrotica virgifera virgifera LeConte, and southern corn rootworm, Diabrotica undecimpunctata howardi Barber. The results also demonstrated that feeding by the aboveground herbivore fall armyworm, Spodoptera frugiperda (J. E. Smith), before infestation by western corn rootworm reduced survivorship of western corn rootworm in the root tissues of some, but not all, genotypes. Likewise, the presence of western corn rootworm in the soil seemed to increase resistance to fall armyworm in the whorl in several genotypes. However, genotypes derived from the Antiguan germplasm with genetic resistance to lepidopterans were still more resistant to the fall armyworm and both rootworm species than the susceptible genotypes even after defense induction. These results suggest that there may be intraplant communication that alters plant responses to aboveground and belowground herbivores.
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Affiliation(s)
- Torrence A Gill
- Department of Crop and Soil Science, 116 ASI Bldg., The Pennsylvania State University, University Park, PA 16802, USA.
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152
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Luthe DS, Gill T, Zhu L, Lopéz L, Pechanova O, Shivaji R, Ankala A, Williams WP. Aboveground to belowground herbivore defense signaling in maize: a two-way street? PLANT SIGNALING & BEHAVIOR 2011; 6:126-9. [PMID: 21270535 PMCID: PMC3122024 DOI: 10.4161/psb.6.1.14255] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Insect pests that attempt to feed on the caterpillar-resistant maize genotype Mp708 encounter a potent, multipronged defense system that thwarts their invasion. First, these plants are on "constant alert" due to constitutively elevated levels of the phytohormone jasmonic acid that signals the plant to activate its defenses. The higher jasmonic acid levels trigger the expression of defense genes prior to herbivore attack so the plants are "primed" and respond with a faster and stronger defense. The second defense is the rapid accumulation of a toxic cysteine protease called Mir1-CP in the maize whorl in response to caterpillar feeding. When caterpillars ingest Mir1-CP, it damages the insect's midgut and retards their growth. In this article, we discuss a third possible defense strategy employed by Mp708. We have shown that foliar caterpillar feeding causes Mir1-CP and defense gene transcripts to accumulate in its roots. We propose that caterpillar feeding aboveground sends a signal belowground via the phloem that results in Mir1-CP accumulation in the roots. We also postulate that the roots serve as a reservoir of Mir1-CP that can be mobilized to the whorl in response to caterpillar assault.
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Affiliation(s)
- Dawn S Luthe
- Department of Crop and Soil Sciences, The Pennsylvania State University, University Park, PA, USA.
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153
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Erb M, Köllner TG, Degenhardt J, Zwahlen C, Hibbard BE, Turlings TCJ. The role of abscisic acid and water stress in root herbivore-induced leaf resistance. THE NEW PHYTOLOGIST 2011; 189:308-20. [PMID: 20840610 DOI: 10.1111/j.1469-8137.2010.03450.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
• Herbivore-induced systemic resistance occurs in many plants and is commonly assumed to be adaptive. The mechanisms triggered by leaf-herbivores that lead to systemic resistance are largely understood, but it remains unknown how and why root herbivory also increases resistance in leaves. • To resolve this, we investigated the mechanism by which the root herbivore Diabrotica virgifera induces resistance against lepidopteran herbivores in the leaves of Zea mays. • Diabrotica virgifera infested plants suffered less aboveground herbivory in the field and showed reduced growth of Spodoptera littoralis caterpillars in the laboratory. Root herbivory did not lead to a jasmonate-dependent response in the leaves, but specifically triggered water loss and abscisic acid (ABA) accumulation. The induction of ABA by itself was partly responsible for the induction of leaf defenses, but not for the resistance against S. littoralis. Root-herbivore induced hydraulic changes in the leaves, however, were crucial for the increase in insect resistance. • We conclude that the induced leaf resistance after root feeding is the result of hydraulic changes, which reduce the quality of the leaves for chewing herbivores. This finding calls into question whether root-herbivore induced leaf-resistance is an evolved response.
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Affiliation(s)
- Matthias Erb
- FARCE Laboratory, University of Neuchâtel, Neuchâtel, Switzerland
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154
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Rasmann S, Bauerle TL, Poveda K, Vannette R. Predicting root defence against herbivores during succession. Funct Ecol 2010. [DOI: 10.1111/j.1365-2435.2010.01811.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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155
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Erb M, Foresti N, Turlings TCJ. A tritrophic signal that attracts parasitoids to host-damaged plants withstands disruption by non-host herbivores. BMC PLANT BIOLOGY 2010; 10:247. [PMID: 21078181 PMCID: PMC3095329 DOI: 10.1186/1471-2229-10-247] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Accepted: 11/15/2010] [Indexed: 05/20/2023]
Abstract
BACKGROUND Volatiles emitted by herbivore-infested plants are highly attractive to parasitoids and therefore have been proposed to be part of an indirect plant defense strategy. However, this proposed function of the plant-provided signals remains controversial, and it is unclear how specific and reliable the signals are under natural conditions with simultaneous feeding by multiple herbivores. Phloem feeders in particular are assumed to interfere with plant defense responses. Therefore, we investigated how attack by the piercing-sucking cicadellid Euscelidius variegatus influences signaling by maize plants in response to the chewing herbivore Spodoptera littoralis. RESULTS The parasitoid Cotesia marginiventris strongly preferred volatiles of plants infested with its host S. littoralis. Overall, the volatile emissions induced by S. littoralis and E. variegatus were similar, but higher levels of certain wound-released compounds may have allowed the wasps to specifically recognize plants infested by hosts. Expression levels of defense marker genes and further behavioral bioassays with the parasitoid showed that neither the physiological defense responses nor the attractiveness of S. littoralis infested plants were altered by simultaneous E. variegatus attack. CONCLUSIONS Our findings imply that plant defense responses to herbivory can be more robust than generally assumed and that ensuing volatiles convey specific information about the type of herbivore that is attacking a plant, even in complex situations with multiple herbivores. Hence, the results of this study support the notion that herbivore-induced plant volatiles may be part of a plant's indirect defense stratagem.
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Affiliation(s)
- Matthias Erb
- Laboratory for Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Nicolas Foresti
- Laboratory for Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Ted CJ Turlings
- Laboratory for Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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156
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157
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Verhage A, van Wees SC, Pieterse CM. Plant immunity: it's the hormones talking, but what do they say? PLANT PHYSIOLOGY 2010; 154:536-40. [PMID: 20921180 PMCID: PMC2949039 DOI: 10.1104/pp.110.161570] [Citation(s) in RCA: 182] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 06/25/2010] [Indexed: 05/18/2023]
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158
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López-Ráez JA, Flors V, García JM, Pozo MJ. AM symbiosis alters phenolic acid content in tomato roots. PLANT SIGNALING & BEHAVIOR 2010; 5:1138-40. [PMID: 21490421 PMCID: PMC3115087 DOI: 10.4161/psb.5.9.12659] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Accepted: 06/10/2010] [Indexed: 05/20/2023]
Abstract
Arbuscular mycorrhizal (AM) fungi colonize the roots of most plants to establish a mutualistic symbiosis leading to important benefits for plant health. We have recently shown that AM symbiosis alters both transcriptional and hormonal profiles in tomato roots, many of these changes related to plant defence. Here, we analytically demonstrate that the levels of other important defence-related compounds as phenolic acids are also altered in the symbiosis. Both caffeic and chlorogenic acid levels significantly decreased in tomato roots upon mycorrhization, while ferulic acid increased. Moreover, in the case of caffeic acid a differential reduction was observed depending on the colonizing AM fungus. The results confirm that AM associations imply the regulation of plant defence responses, and that the host changes may vary depending on the AM fungus involved. The potential implications of altered phenolic acid levels on plant control over mycorrhizal colonization and in the plant resistance to pathogens is discussed.
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Affiliation(s)
- Juan A López-Ráez
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (CSIC), Granada, Spain.
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159
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Erb M, Glauser G. Family Business: Multiple Members of Major Phytohormone Classes Orchestrate Plant Stress Responses. Chemistry 2010; 16:10280-9. [DOI: 10.1002/chem.201001219] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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160
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Shivaji R, Camas A, Ankala A, Engelberth J, Tumlinson JH, Williams WP, Wilkinson JR, Luthe DS. Plants on constant alert: elevated levels of jasmonic acid and jasmonate-induced transcripts in caterpillar-resistant maize. J Chem Ecol 2010; 36:179-91. [PMID: 20148356 DOI: 10.1007/s10886-010-9752-z] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 01/03/2010] [Accepted: 01/15/2010] [Indexed: 12/20/2022]
Abstract
This study was conducted to determine if constitutive levels of jasmonic acid (JA) and other octadecanoid compounds were elevated prior to herbivory in a maize genotype with documented resistance to fall armyworm (Spodoptera frugiperda) and other lepidopteran pests. The resistant inbred Mp708 had approximately 3-fold higher levels of jasmonic acid (JA) prior to herbivore feeding than the susceptible inbred Tx601. Constitutive levels of cis-12-oxo-phytodienoic acid (OPDA) also were higher in Mp708 than Tx601. In addition, the constitutive expression of JA-inducible genes, including those in the JA biosynthetic pathway, was higher in Mp708 than Tx601. In response to herbivory, Mp708 generated comparatively higher levels of hydrogen peroxide, and had a greater abundance of NADPH oxidase transcripts before and after caterpillar feeding. Before herbivore feeding, low levels of transcripts encoding the maize insect resistance cysteine protease (Mir1-CP) and the Mir1-CP protein were detected consistently. Thus, Mp708 appears to have a portion of its defense pathway primed, which results in constitutive defenses and the ability to mount a stronger defense when caterpillars attack. Although the molecular mechanisms that regulate the constitutive accumulation of JA in Mp708 are unknown, it might account for its enhanced resistance to lepidopteran pests. This genotype could be valuable in studying the signaling pathways that maize uses to response to insect herbivores.
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Affiliation(s)
- Renuka Shivaji
- Department of Biochemistry and Molecular Biology, Mississippi State University, Mississippi State, MS 39762, USA
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161
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Heil M, Ton J. Systemic Resistance Induction by Vascular and Airborne Signaling. PROGRESS IN BOTANY 2010. [DOI: 10.1007/978-3-642-02167-1_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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162
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Erb M, Lenk C, Degenhardt J, Turlings TCJ. The underestimated role of roots in defense against leaf attackers. TRENDS IN PLANT SCIENCE 2009; 14:653-9. [PMID: 19736036 DOI: 10.1016/j.tplants.2009.08.006] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 08/04/2009] [Accepted: 08/10/2009] [Indexed: 05/23/2023]
Abstract
Plants have evolved intricate strategies to withstand attacks by herbivores and pathogens. Although it is known that plants change their primary and secondary metabolism in leaves to resist and tolerate aboveground attack, there is little awareness of the role of roots in these processes. This is surprising given that plant roots are responsible for the synthesis of plant toxins, play an active role in environmental sensing and defense signaling, and serve as dynamic storage organs to allow regrowth. Hence, studying roots is essential for a solid understanding of resistance and tolerance to leaf-feeding insects and pathogens. Here, we highlight this function of roots in plant resistance to aboveground attackers, with a special focus on systemic signaling and insect herbivores.
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Affiliation(s)
- Matthias Erb
- Laboratory for Fundamental and Applied Research in Chemical Ecology, University of Neuchâtel, Neuchâtel, Switzerland.
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163
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Navia-Giné WG, Gomez SK, Yuan J, Chen F, Korth KL. Insect-induced gene expression at the core of volatile terpene release in Medicago truncatula. PLANT SIGNALING & BEHAVIOR 2009. [PMID: 19820332 PMCID: PMC2710562 DOI: 10.4161/psb.4.7.8973] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The blends of induced volatiles released by higher plants in response to herbivory regularly contain terpenoids. The precursors of volatile terpenoids can be synthesized via two pathways, the mevalonate (MVA) and the methyl erythritol 4-phosphate (MEP) pathways localized in the cytosol and in plastids, respectively. Terpenes are important players in interactions between plants and herbivorous insects, by acting in both direct and indirect defenses. We recently characterized a gene encoding an (E)-beta-ocimene synthase (MtEBOS) in the legume Medicago truncatula Gaertn. Compared to undamaged plants, caterpillar-damaged M. truncatula emitted (E)-beta-ocimene at an elevated level and this increase is associated with high levels of expression of MtEBOS mRNA. Exogenous treatment with jasmonic acid also increases transcript accumulation of MtEBOS. These results indicate that transcript accumulation is used as a tightly regulated mechanism to control (E)-beta-ocimene emission. The data, along with additional findings in other species, illustrate that like most plant families legumes regulate the final steps of volatile terpene biosynthesis at the level of transcript induction.
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Affiliation(s)
- Wayra G Navia-Giné
- Department of Plant Pathology, University of Arkansas, Fayetteville, AR, USA
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