Bacillus thuringiensis DB27 Produces Two Novel Protoxins, Cry21Fa1 and Cry21Ha1, Which Act Synergistically against Nematodes

Iatsenko, Igor; Boichenko, Iuliia; Sommer, Ralf J.

doi:10.1128/aem.00464-14

Cited by 41 publications

(31 citation statements)

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“…This PI was also reported to be resistant to all known SCN HG Types and several resistance QTLs have been mapped from this source (Concibido et al 2004). Iatsenko et al (2014) reported that Bacillus thuringiensis DB27 produces two protoxins, Cry21Fa1 and Cry21Ha1, which act synergistically against nematodes. Studham et al (2009) conducted a study to identify whether Rag1, a single dominant gene for aphid resistance also confers resistance to both SCN and RKN similar to Mi-1.2, a tomato gene that confers resistance to both aphid and RKN.…”

Section: Discussionmentioning

confidence: 94%

Reaction of Soybean Cyst Nematode Resistant Plant Introductions to Root-Knot and Reniform Nematodes

Lee¹,

Kim²,

Robbins³

et al. 2015

Plant Breed. Biotech.

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This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Out of these accessions, 64 PIs were identified with high or moderate resistance to RKN. Of these 64 lines, 24 accessions showed good resistance to both RKN and RN. These new sources of resistance to multiple nematodes will be valuable materials for soybean breeding programs to develop new resistant cultivars that can overcome yield losses caused by one or more of these nematode species.

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Section: Discussionmentioning

confidence: 94%

Reaction of Soybean Cyst Nematode Resistant Plant Introductions to Root-Knot and Reniform Nematodes

Lee¹,

Kim²,

Robbins³

et al. 2015

Plant Breed. Biotech.

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“…Our previous studies have sequenced the genome of strain YBt-1518, from which three nematicidal Cry proteins (19), as well as Bmp1, chitinase (20), and other assistant virulence factors (21), were identified and appraised. Additionally, within the genome of nematicidal B. thuringiensis DB27, several Cry protein genes against nematodes were also identified (6,22).…”

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confidence: 99%

“…Although many Cry toxins are known to target various insects, only a few nematicidal crystal protein genes, particularly those targeting plant-parasitic nematodes (PPNs), have been found and utilized, of which only cry5Ba and cry6Aa have been applied into transgenic tomatoes (14)(15)(16). These nematicidal Cry toxins cluster together in phylogenetic subfamilies (17); the Cry5, Cry13A, Cry14A, and Cry21 proteins share the same evolutionary ancestry and are thus clustered into the Cry5 subfamily, which includes the nontoxic proteins Cry5A and Cry21G (6). Out of these nematicidal toxins, only Cry6Aa and Cry55Aa differ from the three-domain (3D) toxin Cry5 subfamily based on phylogenetic analysis and bioassays (18).…”

mentioning

confidence: 99%

“…The most successful commercially available biopesticide for agricultural pest biocontrol, Bacillus thuringiensis (Bt), is a ubiquitous Gram-positive bacterium that produces insecticidal and nematicidal parasporal crystals during the sporulation phase (4,5). Combined with other assistant virulence factors, crystal proteins contribute to its pathogenesis during infection of the host insect or worm (6,7). Although the number of identified nematicidal Bt strains is increasing (8) (relative to the amount of insecticidal Bt), additional nematode control resources are needed.…”

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confidence: 99%

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Dissimilar Crystal Proteins Cry5Ca1 and Cry5Da1 Synergistically Act against Meloidogyne incognita and Delay Cry5Ba-Based Nematode Resistance

Geng

Liu

et al. 2017

Appl Environ Microbiol

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Cry proteins of Bacillus thuringiensis (Bt) have been successfully used as biopesticides and in transgenic crops throughout the world. However, resources against the most serious agricultural pathogens, plant root-knot nematodes, are limited. The genomes of several highly nematicidal virulent Bt strains from our laboratory have been sequenced, facilitating the identification of novel Cry proteins and other virulence factors. We identified two novel Cry proteins, Cry5Ca1 and Cry5Da1, that exhibit high toxicity against Meloidogyne incognita. Using the Caenorhabditis elegans model, the two Cry5 toxins were shown to negatively affect nematode life span, fertility, and survival. The 50% lethal concentrations (LC 50 s) of Cry5Ca1 and Cry5Da1 were 57.22 g/ml and 36.69 g/ml, respectively. Moreover, a synergistic effect (synergism factor, 1.61 to 2.04) was observed for nematicidal toxicity of Cry5Ca1 and Cry5Da1, which is accordant with the phylogenetic results suggesting that domain II of the two novel Cry5 toxins evolved into two independent clades. Through comparison of the depressed degree of toxicity in the ␤-methylgalactoside detoxification test, we found that the novel toxin Cry5D possesses a different galactosebinding epitope; meanwhile, the finding that Cry5D does not share a motif (GXXXE) in the corresponding loop of domain II with Cry5B could explain the different galactose binding performance. Additionally, low-level cross-resistance of C. elegans bre mutant strains was evident between Cry5B and Cry5D. These results suggest that Cry5D can be used as an alternative to delay the potential resistance of nematodes to Cry5B. IMPORTANCE Although proper gene resources for Bt crops against the most serious agricultural pathogens, plant root-knot nematodes, are limited, we have identified two novel nematicidal toxins, Cry5Ca1 and Cry5Da1, against M. incognita, which have supplied more gene candidates for Bt crops designed against nematodes. Moreover, the association of the dissimilarity between Cry5Da1 and Cry5Ba1 and their low crossresistance can be attributed not only to a low sequence similarity of domain II but also to the structural difference of the key motif and receptor-binding epitope in the loops. This association facilitates the selection of a proper candidate for the prospective design of pyramided Bt crops that can delay potential resistance.KEYWORDS Bacillus thuringiensis, Caenorhabditis elegans, Cry proteins, bre resistance, nematicidal T he agricultural economic damage caused by more than 4,100 species of plantparasitic nematodes (PPNs) has been estimated to cost US$80 billion per year (1, 2), and a large proportion of this cost is due to the serious damage caused by the plant-parasitic nematode Meloidogyne incognita (3). Although many nematophagous

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“…To accomplish this, we first transferred all individuals on prey plates to NGM plates with OP50, letting both species recover from starvation for 2 days (days 3-4). Following this recovery period, we recruited a pathogenic strain of bacteria, Bacillus thuringiensis strain DB27, that after 24 h of exposure is completely lethal to C. elegans but not at all to P. pacificus [33,34]. One day after administering DB27 to plates in a quantity of 60 ml in lysogenic broth per plate (day 5), P. pacificus offspring could be readily distinguished and counted.…”

Section: (A) Predation Assaymentioning

confidence: 99%

Adaptive value of a predatory mouth-form in a dimorphic nematode

2014

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Polyphenisms can be adaptations to environments that are heterogeneous in space and time, but to persist they require conditional-specific advantages. The nematode Pristionchus pacificus is a facultative predator that displays an evolutionarily conserved polyphenism of its mouthparts. During development, P. pacificus irreversibly executes either a eurystomatous (Eu) or stenostomatous (St) mouth-form, which differ in the shape and number of movable teeth. The Eu form, which has an additional tooth, is more complex than the St form and is thus more highly derived relative to species lacking teeth. Here, we investigate a putative fitness trade-off for the alternative feeding-structures of P. pacificus. We show that the complex Eu form confers a greater ability to kill prey. When adults were provided with a prey diet, Eu nematodes exhibited greater fitness than St nematodes by several measures, including longevity, offspring survival and fecundity when followed by bacterial feeding. However, the two mouthforms had similar fecundity when fed ad libitum on bacteria, a condition that would confer benefit on the more rapidly developing St form. Thus, the two forms show conditional fitness advantages in different environments. This study provides, to our knowledge, the first functional context for dimorphism in a model for the genetics of plasticity.

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Bacillus thuringiensis DB27 Produces Two Novel Protoxins, Cry21Fa1 and Cry21Ha1, Which Act Synergistically against Nematodes

Cited by 41 publications

References 45 publications

Reaction of Soybean Cyst Nematode Resistant Plant Introductions to Root-Knot and Reniform Nematodes

Reaction of Soybean Cyst Nematode Resistant Plant Introductions to Root-Knot and Reniform Nematodes

Dissimilar Crystal Proteins Cry5Ca1 and Cry5Da1 Synergistically Act against Meloidogyne incognita and Delay Cry5Ba-Based Nematode Resistance

Adaptive value of a predatory mouth-form in a dimorphic nematode

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