New Bacillus thuringiensis strain isolated from the gut of Malabari goat is effective against Tetranychus macfarlanei

Abstract

This study illustrates a novel strain (designated as BPU5) of Bacillus thuringiensis (Bt) isolated from the rumen of Malabari goat, capable of producing polymorphic δ‐endotoxin crystals concomitantly with sporulation in Luria–Bertani medium (LB), and the δ‐endotoxin was efficient to combat Tetranychus macfarlanei, a devastating mite. Polymorphic δ‐endotoxin crystals produced were assessed by scanning electron microscopy and monitored its production concomitantly with sporulation in LB with or without sugar supplements. Toxicity of the δ‐endotoxin was assessed on T. macfarlanei using leaf disc bioassay method. Mortality rate was determined by comparing the survival of mites on the diet (prepared in 10% sucrose and powdered rice husk) containing different concentrations (1–10 mg/ml) of 72‐h‐old crude pellet (dried mixture of δ‐endotoxin (17 mg/g pellet), endospores and a few vegetative cells) or control diet with autoclaved pellet. The maximum production (1.39 mg/ml) of δ‐endotoxin was observed at 72 h in LB. Among the sugars (glucose, sucrose, maltose or lactose) tested as additional carbon source, glucose (8 g/l) enhanced (1.82 mg/ml) the production of δ‐endotoxin by 30%. The lethal concentration (LC50) required to kill 50% mites was estimated as 8.024 mg/ml. The δ‐endotoxin produced by B. thuringiensis BPU5 is shown to efficiently combat T. macfarlanei, a devastating mite infesting agricultural fields.

Current Insights on Vegetative Insecticidal Proteins (Vip) as Next Generation Pest Killers

“…The discovery of new isolates not only helped in the production of new pesticides of a wide insecticidal spectrum, but also in overcoming insecticidal resistance [80]. B. thuringiensis strains were isolated from diverse habitats, like milk and mossy pine cone [81], soil, leaf [82] and insect cadavers [83], and goat gut [84].…”

Molecular characterization of indigenous Bacillus thuringiensis strains isolated from Kashmir valley

“…There are reports of Bt strains active against livestock ectoparasites (Gough et al 2002) and nematodes (Wei et al 2003). Recently several reports of Bt and its toxicity against various insect pests have been documented (Ozturk et al 2008;de Escudero et al 2014;Neethu et al 2015). Cry toxins' primary action is to lyse midgut epithelial cells by inserting into the target membrane and forming pores (Bravo et al 2007).…”

Using Plant Growth-promoting Fungi (PGPF), as a Biofertilizer and Biocontrol Agents against Tetranychus cucurbitacearum on Nubian Watermelon (Citrullus lanatus L.)

“…Nowadays, agricultural sector has been facing the destructive activities of numerous pests like insects and weeds leading to significant decrease in many agricultural crops [1]. For example, in insect pests, the two-spotted spider mite, Tetranychus cucurbitacearum, consider a polyphase pest which can infest the plants and pierces the epidermis and feeds on the contents of mesophyll cells that results in chlorosis and due to a decrease in total chlorophyll content and an eventual loss of photosynthetic capacity and sometimes the plants will often die [2,3].…”