Lack of cross‐resistance to Mtx1 from Bacillus sphaericus in B. sphaericus‐resistant Culex quinquefasciatus (Diptera: Culicidae)

Wei, Suzhen; Cai, Quan; Cai, Yajun; Yuan, Zhiming

doi:10.1002/ps.1319

Cited by 7 publications

(5 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…quinquefasciatus , suggesting that Mtx1 has a different mode of action than Bin and lacks cross-resistance to B. sphaericus -resistant Cx. quinquefasciatus (Wei et al, 2007). …”

Section: Resistance and Receptorsmentioning

confidence: 99%

Properties and applied use of the mosquitocidal bacterium, Bacillus sphaericus

Park¹,

Bideshi²,

Federici³

2010

Journal of Asia-Pacific Entomology

View full text Add to dashboard Cite

Strains of Bacillus sphaericus exhibit varying levels of virulence against mosquito larvae. The most potent strain, B. sphaericus 2362, which is the active ingredient in the commercial product VectoLex®, together with another well-known larvicide Bacillus thuringiensis subsp. israelensis, are used to control vector and nuisance mosquito larvae in many regions of the world. Although not all strains of B. sphaericus are mosquitocidal, lethal strains produce one or two combinations of three different types of toxins. These are (1) the binary toxin (Bin) composed of two proteins of 42 kDa (BinA) and 51 kDa (BinB), which are synthesized during sporulation and co-crystallize, (2) the soluble mosquitocidal toxins (Mtx1, Mtx2 and Mtx3) produced during vegetative growth, and (3) the two-component crystal toxin (Cry48Aa1/Cry49Aa1). Non-mosquitocidal toxins are also produced by certain strains of B. sphaericus, for examples sphaericolysin, a novel insecticidal protein toxic to cockroaches. Larvicides based on B. sphaericus-based have the advantage of longer persistence in treated habitats compared to B. thuringiensis subsp. israelensis. However, resistance is a much greater threat, and has already emerged at significant levels in field populations in China and Thailand treated with B. sphaericus. This likely occurred because toxicity depends principally on Bin rather than various combinations of crystal (Cry) and cytolytic (Cyt) toxins present in B. thuringiensis subsp. israelensis. Here we review both the general characteristics of B. sphaericus, particularly as they relate to larvicidal isolates, and strategies or considerations for engineering more potent strains of this bacterium that contain built-in mechanisms that delay or overcome resistance to Bin in natural mosquito populations.

show abstract

“…quinquefasciatus , suggesting that Mtx1 has a different mode of action than Bin and lacks cross-resistance to B. sphaericus -resistant Cx. quinquefasciatus (Wei et al, 2007). …”

Section: Resistance and Receptorsmentioning

confidence: 99%

Properties and applied use of the mosquitocidal bacterium, Bacillus sphaericus

Park¹,

Bideshi²,

Federici³

2010

Journal of Asia-Pacific Entomology

View full text Add to dashboard Cite

show abstract

“…israelensis Cry-toxins and toxin combinations, including Cry4Aa, Cry4Ba, Cry4Aa + Cry4Ba, Cry4Aa + CryBa + Cry11Aa, and Cry4Aa + CryBa + Cry11Aa + Cyt1Aa. The presence of cross-resistance in Cry-toxin selected C. quinquefasciatus is intriguing because of the absence of any such cross-resistance in L. sphaericus resistant mosquitoes (Wirth et al, 2007; Wei et al, 2007). In view of the significant cross-resistance shown among the various Cry toxins from B. thuringiensis subsp.…”

Section: Discussionmentioning

confidence: 99%

Mtx toxins from Lysinibacillus sphaericus enhance mosquitocidal cry-toxin activity and suppress cry-resistance in Culex quinquefasciatus

Wirth

Berry

Walton

et al. 2014

Journal of Invertebrate Pathology

View full text Add to dashboard Cite

The interaction of Mtx toxins from Lysinibacillus sphaericus (formerly Bacillus sphaericus) with Bacillus thuringiensis subsp. israelensis Cry toxins and the influence of such interactions on Cry-resistance were evaluated in susceptible and Cry-resistant Culex quinquefasciatus larvae. Mtx-1 and Mtx-2 were observed to be active against both susceptible and resistant mosquitoes; however varying levels of cross-resistance toward Mtx toxins were observed in the resistant mosquitoes. A 1:1 mixture of either Mtx-1 or Mtx-2 with different Cry toxins generally showed moderate synergism, but some combinations were highly toxic to resistant larvae and suppressed resistance. Toxin synergy has been demonstrated to be a powerful tool for enhancing activity and managing Cry-resistance in mosquitoes, thus Mtx toxins may be useful as components of engineered bacterial larvicides.

show abstract

“…in the B. sphaericus-resistant populations, their susceptibility to B. sphaericus C3-41 recovered, with the resistance ratio of fieldcollected larvae declining from 22,672-fold to 5.67-fold [41]; the gene exchange with populations in surrounding untreated areas may also have contributed to the rapid decline of resistance levels. There is a lack of cross-resistance between binary toxins and Mtx toxins [76], indicating that Mtx could be a potential tool to manage resistance to binary toxins in the future. It was suggested that once resistance to B. sphaericus is detected in the field, its use should be discontinued until the mosquito population becomes susceptible again because of the decline in number of resistant individuals [77].…”

Section: Resistance Managementmentioning

confidence: 99%

Resistance and Its Management to Microbial and Insect Growth Regulator Larvicides in Mosquitoes

Su¹

2016

Insecticides Resistance

View full text Add to dashboard Cite

Mosquito larvicides derived from microbial organisms and insect growth regulators have been increasingly used to control mosquito larvae worldwide. Their relative target specificity, nontarget safety, and environmentally friendly profile have been well documented. The current chapter was intended to review and analyze the relevant information regarding resistance development and resistance management tactics. Bacillus thuringiensis israelensis de Bajac B.t.i. is a quick-acting and highly target-specific biopesticide against mosquitoes, blackflies, and other nematoceran species. Resistance development toward intact complementary toxin complex of B.t.i. was rare however, low to high levels of resistance to individual toxins have occurred in laboratory mosquito populations. The toxins from bacterium Bacillus sphaericus Neide recently renamed Lysinibacillus sphaericus Meyer and Neide is another highly active larvicide against mosquitoes, toward which low to high levels of resistance have occurred in both laboratory and field mosquito populations. The Cyt A toxin from B.t.i. and Mtx toxin from certain strains of B. sphaericus are the key components in resistance management to B.t.i. and B. sphaericus. The resistance management strategies have been well developed and implemented. Spinosad derived from Saccharopolyspora spinosa Mertz and Yao has been recently used for mosquito control high levels of resistance and cross-resistance have occurred in laboratory mosquito populations and no management tactics have ever been developed. Methoprene has been used to control mosquitoes for decades, and low to high levels of resistance have been occasionally reported in both laboratory and field mosquito populations. Studies on mechanism and management of methoprene resistance are quite meager. Very little attention has been paid to the resistance management in mosquitoes to other insect growth regulators such as pyriproxyfen and diflubenzuron. The prevention of resistance and restoration of susceptibility in mosquitoes to these biorational larvicides are crucial to the success of sustainable integrated mosquito management.

show abstract

Lack of cross‐resistance to Mtx1 from Bacillus sphaericus in B. sphaericus‐resistant Culex quinquefasciatus (Diptera: Culicidae)

Cited by 7 publications

References 19 publications

Properties and applied use of the mosquitocidal bacterium, Bacillus sphaericus

Properties and applied use of the mosquitocidal bacterium, Bacillus sphaericus

Mtx toxins from Lysinibacillus sphaericus enhance mosquitocidal cry-toxin activity and suppress cry-resistance in Culex quinquefasciatus

Resistance and Its Management to Microbial and Insect Growth Regulator Larvicides in Mosquitoes

Contact Info

Product

Resources

About