Toxins for Transgenic Resistance to Hemipteran Pests

Chougule, Nanasaheb P.; Bonning, Bryony C.

doi:10.3390/toxins4060405

Cited by 139 publications

(97 citation statements)

References 167 publications

(193 reference statements)

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“…Unlike lepidopteran and coleopteran pests, Bacillus thuringiensis (Bt) toxins exhibit little toxicity against sap-sucking hemipteran pests (Raps et al, 2001;Gatehouse, 2008;Chougule and Bonning, 2012). Furthermore, Bt maize supports higher aphid populations compared with non-Bt maize (Faria et al, 2007), suggesting that better management practices are required to control hemipteran sap-sucking pests.…”

Section: Discussionmentioning

confidence: 99%

Ethylene Contributes to maize insect resistance1-Mediated Maize Defense against the Phloem Sap-Sucking Corn Leaf Aphid

et al. 2015

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ORCID IDs: 0000-0001-7137-8797 (J.L.); 0000-0002-3904-6984 (S.B.); 0000-0003-3192-978X (S.V.); 0000-0002-3550-5522 (V.J.); 0000-0001-9147-3871 (W.P.W.).Signaling networks among multiple phytohormones fine-tune plant defense responses to insect herbivore attack. Previously, it was reported that the synergistic combination of ethylene (ET) and jasmonic acid (JA) was required for accumulation of the maize insect resistance1 (mir1) gene product, a cysteine (Cys) proteinase that is a key defensive protein against chewing insect pests in maize (Zea mays). However, this study suggests that mir1-mediated resistance to corn leaf aphid (CLA; Rhopalosiphum maidis), a phloem sap-sucking insect pest, is independent of JA but regulated by the ET-signaling pathway. Feeding by CLA triggers the rapid accumulation of mir1 transcripts in the resistant maize genotype, Mp708. Furthermore, Mp708 provided elevated levels of antibiosis (limits aphid population)-and antixenosis (deters aphid settling)-mediated resistance to CLA compared with B73 and Tx601 maize susceptible inbred lines. Synthetic diet aphid feeding trial bioassays with recombinant Mir1-Cys Protease demonstrates that Mir1-Cys Protease provides direct toxicity to CLA. Furthermore, foliar feeding by CLA rapidly sends defensive signal(s) to the roots that trigger belowground accumulation of the mir1, signifying a potential role of long-distance signaling in maize defense against the phloem-feeding insects. Collectively, our data indicate that ET-regulated mir1 transcript accumulation, uncoupled from JA, contributed to heightened resistance to CLA in maize. In addition, our results underscore the significance of ET acting as a central node in regulating mir1 expression to different feeding guilds of insect herbivores.

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Section: Discussionmentioning

confidence: 99%

Ethylene Contributes to maize insect resistance1-Mediated Maize Defense against the Phloem Sap-Sucking Corn Leaf Aphid

et al. 2015

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“…Insect resistant transgenic crops that express insect-specific toxins derived from the bacterium Bacillus thuringiensis (Bt), have provided effective suppression of lepidopteran (moth) and coleopteran (beetle) pests and have been widely adopted in the United States and elsewhere (2,3). However, the sap-sucking hemipteran pests are not particularly susceptible to the Bt-derived toxins (4)(5)(6). Indeed, in some cases, chemical insecticides have to be applied to curtail damage caused by hemipteran pests on Bt transgenic crops, such that the benefit of using the insect resistant transgenic varieties is lost (7)(8)(9).…”

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confidence: 99%

Retargeting of the Bacillus thuringiensis toxin Cyt2Aa against hemipteran insect pests

Chougule

Liu

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Although transgenic crops expressing Bacillus thuringiensis (Bt) toxins have been used successfully for management of lepidopteran and coleopteran pest species, the sap-sucking insects (Hemiptera) are not particularly susceptible to Bt toxins. To overcome this limitation, we demonstrate that addition of a short peptide sequence selected for binding to the gut of the targeted pest species serves to increase toxicity against said pest. Insertion of a 12-aa pea aphid gut-binding peptide by adding to or replacing amino acids in one of three loops of the Bt cytolytic toxin, Cyt2Aa, resulted in enhanced binding and toxicity against both the pea aphid, Acyrthosiphon pisum, and the green peach aphid, Myzus persicae. This strategy may allow for transgenic plant-mediated suppression of other hemipteran pests, which include some of the most important pests of global agriculture.aphid management | biotechnology | insect resistance

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“…Chrysomelid beetles and cicadellid hemipterans dominated the assemblages on plants of both ecotypes, but different species were collected from the two different soil types. Chrysomelids and cicadellids are known to have neutral to acidic gut pH's (Knowles 1994;Chougule and Bonning 2012). In this pH range, PC-protein binding is kinetically favored and therefore could represent one possible defense mechanism against these herbivores.…”

Section: Discussionmentioning

confidence: 99%

Habitat-specific divergence of procyanidins in Protium subserratum (Burseraceae)

et al. 2015

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In Amazonian Peru, the neotropical tree Protium subserratum Engl. (Burseraceae) occurs as distinct ecotypes on low nutrient white-sand (WS), intermediate fertility brown-sand (BS), and nutrient-rich clay (CS) soils. Genetic analysis indicates that these ecotypes are undergoing incipient speciation. Possible drivers of this divergence are habitat-specific herbivore faunas and differing resource availabilities. Protium subserratum, therefore, provides an ideal opportunity to investigate how defense chemistry evolves during lineage divergence. WS and BS races of P. subserratum are host to largely nonoverlapping herbivore communities and they differ in chlorogenic acid, flavonoid, and oxidized terpene chemistry. Here, we investigate how another important class of anti-herbivore chemicals, procyanidins (PCs), varies among the ecotypes. We isolated the PCs from leaves of juvenile and adult trees from each ecotype and used spectroscopic and chemical techniques to characterize the chemical structures of their component monomers. We found that WS, BS, and CS ecotypes accumulate ca. 17 % of leaf dry weight as PCs. Within ecotypes, we found very little difference in PC type, neither by site nor by life stage.Among ecotypes, however, we observed a marked divergence in PC composition that arose at least in part from differences in their terminal and extension subunits. In addition, the average polymer length of BS and CS PCs was significantly greater than in WS ecotypes. We conclude that phenotypic differences in PCs in the WS versus BS and CS ecotypes of P. subserratum are consistent with selection by herbivores in different soil types that differ strongly in nutrient availability and may contribute to the evolution of habitat specialization.

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Toxins for Transgenic Resistance to Hemipteran Pests

Cited by 139 publications

References 167 publications

Ethylene Contributes to maize insect resistance1-Mediated Maize Defense against the Phloem Sap-Sucking Corn Leaf Aphid

Ethylene Contributes to maize insect resistance1-Mediated Maize Defense against the Phloem Sap-Sucking Corn Leaf Aphid

Retargeting of the Bacillus thuringiensis toxin Cyt2Aa against hemipteran insect pests

Habitat-specific divergence of procyanidins in Protium subserratum (Burseraceae)

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