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A new Cry toxin with a unique two‐component dependency from Bacillus sphaericus
Author(s) -
Jones Gareth W.,
NielsenLeroux Christina,
Yang Yankun,
Yuan Zhiming,
Fiúza Dumas Vinícius,
Monnerat Rose Gomes,
Berry Colin
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.07-8913com
Subject(s) - bacillus sphaericus , bacillus thuringiensis , toxin , pore forming toxin , biology , culex quinquefasciatus , microbiology and biotechnology , bacillus subtilis , bacillaceae , bacteria , bacillales , genetics , larva , microbial toxins , botany , aedes aegypti
Highly pathogenic strains of Bacillus sphaericus produce the mosquitocidal Bin proteins, but resistance to this toxin can be produced under laboratory and field conditions. Analysis of strains able to overcome this resistance revealed the presence of a previously undescribed type of two‐component toxin. One subunit, Cry48Aa1, is related to the 3‐domain crystal toxins of Bacillus thuringiensis . Uniquely for this type of protein, insect toxicity is only achieved in the presence of a second, accessory protein, Cry49Aa1. This protein is itself related to both the binary toxin of B. sphaericus and to Cry35 and Cry36 of B. thuringiensis, none of which require interaction with Cry48Aa1‐like proteins for their activity. The necessity for both Cry48Aa1 and Cry49Aa1 components for pathogenicity, therefore, indicates an unprecedented interaction to generate toxicity. Despite high potency for purified Cry48Aa1/Cry49Aa1 proteins (LC 50 for third instar Culex quinquefasciatus larvae: 15.9 ng/ml and 6.3 ng/ml respectively), bacteria producing them show suboptimal mosquitocidal activity due to low‐level Cry48Aa1 production. This new toxin combination may indicate a fortuitous combination of members of the gene families that encode 3‐domain Cry toxins and Binary‐like toxins, permitting the “mix‐and‐match” evolution of a new component in the mosquitocidal armoury.— Jones G. W., Nielsen‐Leroux, C., Yang, Y., Yuan, Z., Dumas, V. F., Monnerat, R. G., Colin Berry C. A new Cry toxin with a unique two‐component dependency from Bacillus sphaericus . FASEB J . 21, 4112–4120 (2007)