Toxicity of a Bacillus thuringiensis israelensis-like strain against Spodoptera frugiperda

Abstract

Bacillus thuringiensis (Bt) Berliner is a promising agent for microbial control of agriculturally and medically important insects. This study aimed at searching for Bt strains encoding Cry proteins that act more efficiently against fall armyworm. Thirty Bt strains were isolated from soil samples in Pernambuco State and evaluated through bioassays. Among these, strain I4A7 was the most efficient against the fall armyworm, Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae), and thus it was characterized by biochemical sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and molecular (polymerase chain reaction (PCR) and sequencing reaction) methods. The protein pattern of this strain on a SDS-PAGE was similar to that of B. thuringiensis israelensis (Bti). Moreover, I4A7 cry DNA sequence showed high identity (99-100%) to genes cry4Aa, 4Ba, 10Aa, 11Aa, cyt1Aa and cyt2B from Bti. The toxicity of the newly isolated Btilike strain upon S. frugiperda should be considered as this strain might be used in combination with other Bt strains, such as B. thuringiensis var. kurstaki (Btk).

Bacillus thuringiensis subsp. israelensis and Its Dipteran-Specific Toxins

“…In addition to mosquitoes, black flies [ 23 ] and chironomid midges [ 24 , 25 ] the expanded host range of Bti includes the following species: Tabanus triceps (Diptera: Tabanidae) [ 26 ], Mexican fruit fly, Anastrepha ludens and Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae) [ 27 , 28 ], Tipula paludosa (Diptera: Nematocera) [ 29 ], fungus gnats, Bradysia coprophila and Bradysia impatiens (Diptera: Sciaridae) [ 30 , 31 ], nodule-damaging fly Rivellia angulata (Diptera: Platystomatidae) [ 32 ], pea aphid Acyrthosiphon pisum (Hemiptera: Aphidoidea) [ 33 ], potato aphid, Macrosiphum euphorbiae (Homoptera: Aphididae) [ 34 ], cotton boll weevil Anthonomus grandis (Coleoptera: Tenebrionidae) [ 35 ], leaf beetle, Chrysomela scripta (Coleoptera: Chrysomelidae) [ 36 ], fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) [ 37 ], diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) [ 38 ], root-knot nematode, Meloidogyne incognita on barley [ 39 ] and trematode species, Schistosoma mansoni and Trichobilharzia szidati (Trematoda: Schistosomatidae) [ 40 ].…”

Relative activity of 15 bacterial strains against the larvae of Helicoverpa armigera, Spodoptera exigua, and Spodoptera litura (Lepidoptera: Noctuidae)

“…Previous research has shown that the significant production of 130–145 kDa proteins may correspond to the expression of cry1A , cry1C , cry1D , and cry1F , but not to cry2 or cyt genes, which code for proteins 70–80 kDa in size (Fig. 7) (Souza et al 2009, Palma et al 2014). Different members of the same Cry family may be present in individual isolate (e.g., Cry1Aa, Cry1Ab, Cry1Ac, Cry2Aa, and Cry2Ab in Bt serovar kurstaki HD-1), and the presence of multiple toxin strains from a single first-level Cry family is common.…”

First Microsatellites fromSpodoptera frugiperda(Lepidoptera: Noctuidae) and Their Potential use for Population Genetics

“…The alternative method of control is the use of transgenic crops expressing Cry toxins from Bacillus thuringiensis (Berliner) (Bt; Bacillales: Bacillaceae) (Jenkins 1999). However, S. frugiperda has shown some level of tolerance to Cry1 F toxin (Adamczyk et al 1997, Chilcutt et al 2007, de Souza et al 2009). In particular, Puerto Rico (PR) fall armyworm populations have already shown high tolerance to the ␦-endotoxin Cry1 F of Bt (Tabashnik et al 2009.…”