Bacillus thuringiensis Bt_UNVM-84, a strain showing a strong insecticidal activity against Anthonomus grandis Boheman (Coleoptera: Curculionidae).

DIEGO SAUKA; CECILIA PERALTA; MELISA PAULA PÉREZ; ANTONELLA MOLLA; TADEO FERNANDEZ-GÖBEL; FEDERICO OCAMPO; LEOPOLDO PALMA*

Toxins

MDPI

Lugar: Basel; Año: 2023

2072-6651

Bacillus thuringiensis is a Gram-positive bacterium known for its insecticidal proteins ef- 6fective against various insect pests. However, limited strains and proteins target coleopteran pests 7like Anthonomous grandis Boheman, causing substantial economic losses in the cotton industry. This 8study focuses on characterizing Bt_UNVM-84, isolated from Oncativo (Argentina), which exhibits 9ovoid to amorphous parasporal crystals and was designated Bt_UNVM-84. Its genome encodes 10genes for the production of two pairs of binary Vpb1/Vpa2 proteins and three Cry-like proteins 11showing similarity with different Cry8 proteins. Interestingly, this gene content was found to be 12conserved in a previously characterized Argentine isolate of B. thuringiensis designated INTA Fr7- 134. SDS-PAGE analysis revealed a major band of 130 kDa that is proteolytically processed to an ap- 14proximately 66 kDa protein fragment by trypsin. Bioassays performed with spore-crystal mixtures 15demonstrated an interesting insecticidal activity against the cotton boll weevil A. grandis neonate 16larvae, resulting in 91 % mortality. Strain Bt_UNVM-84 is, therefore, an interesting candidate for the 17efficient biological control of this species, causing significant economic losses in cotton industry in 18the Americas.