Expression of thurincin H, ChiA74 and Cry proteins at the sporulation phase in Bacillus thuringiensis HD1

Abstract

Aims:The objective of this study was to produce thurincin H, ChiA74 and Cry proteins together using Bacillus thuringiensis subsp. kurstaki HD1 as a heterologous host. Methods and Results: pSTAB-ThurH and pSTAB-ChiA74 constructs were designed to produce thurincin H and chitinase, respectively, at the sporulation phase.They were transformed into Bt HD1 generating the recombinant strains HD1/ pSTAB-ThurH and HD1/pSTAB-ThurH/pSTAB-ChiA74. Antimicrobial and chitinolytic activity tests were performed with recombinant strains. Both strains were able to produce thurincin H up to 72 h with antibacterial activity of ~4000 U mg −1 .The HD1/pSTAB-ThurH/pSTAB-ChiA74 strain also showed chitinolytic activity of ~23 mU mg −1 at 72 h. All B. thuringiensis strains exhibited crystal formation at 72, and 96 h. In addition, the application of thurincin H in corn seeds increased the germination percentage and root length by 7% and 10%, respectively. Conclusions:We showed that is possible to produce three proteins of biotechnological interest at the sporulation stage in B. thuringiensis, which two of them (thurincin H, and ChiA74) are naturally expressed in the vegetative stage.Significance and Impact of the Study: These results form the basis for developing of a biocontrol and biostimulator product that can be used as an alternative for chemical application.

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

“…Figures were plotted using GraphPad Prism 6 (GraphPad Software, CA, USA). Dose-mortality data were analyzed using the probit method according to Finney (Finney 1971). The slope and intercept of the dose-response curve were estimated using SPSS v22.0, and the LC 20 (Lethal Concentration for 20%), LC 50 (Lethal Concentration for 50%) values of the different insecticides for each pest were evaluated.…”

“…Most of the isolated strains showed catalase amylohydrolysis and indole properties (Table 2), which are consistent with the physiological and biochemical characteristics of Bt subsp. kurstaki strain HD-1 (Ref) (Porcar et al 2000, Porcar et al 2003, Ardahan Eski et al 2018, Gaona Mendoza et al 2021, Park et al 2022). In the present study, 11 general primers previously used for cry gene identification in lepidopteran pests were used.…”

Evaluation of inhibitory compounds produced by bacteria isolated from a hydrogen-producing bioreactor during the self-fermentation of wheat straw

“…Bacteria produce bacteriocins at the ribosomal level, and it has been reported that more than 99% of these microorganisms are able to synthesize these AMPs (Riley & Wertz, 2002). Bacteriocins have been used as food preservatives, in health to treat bacterial infections, as spermicidal agents, anticancer agents, for skin and oral care, in nutrition as modulators of the gastrointestinal microbiota, and in agriculture as biocontrol agents and plant growth promoters (Cesa‐Luna et al, 2021; Gaona‐Mendoza et al, 2021; Negash & Tsehai, 2020). Bacteriocins produced by lactic acid bacteria (LAB), primarily those used as probiotic, have been studied extensively (Alvarez‐Sieiro et al, 2016).…”