The nematicidal activity of Bacillus thuringiensis Cry1Ia36 expressing in Escherichia coli

Abstract

Plant-parasitic nematodes (PPNs) are a significant threat to numerous agricultural crops. Biocontrol is an effective and safe method of the managing PPNs. Bacillus thuringiensis (Bt) and its parasporal crystal proteins (ICPs) are important biocontrol resources for PPNs. In this study, the 2160-bp cry1Ia36 gene from the Bt YC-10 strain was expressed in Escherichia coli and the 81-kDa protein was purified. The nematicidal activity test yielded an LC₅₀ of 12.79 mg/L at 96 h for the second stage juveniles (J2s) of Meloidogyne incognita, and the Cry1Ia36 protein exhibited a pronounced inhibitory effect on the infection of M. incognita to cucumber roots with the pot experiment, which the control effect was 76.95 % treated with 40 mg/L Cry1Ia36. Transgenic tomatoes that expressed the cry1Ia36 gene exhibited efficient control of M. incognita, showing a notable reduction in the number of galls and eggmasses compared to the control. Subsequent transcriptome analysis revealed substantial alterations in the expression patterns of numerous genes in M. incognita J2s treated with Cry1Ia36 protein. Furthermore, the yeast two-hybrid analysis and pull-down assays demonstrated an interaction protein in M. incognita and the interaction protein is associated with the nematicidal activity of Cry1Ia36. Consequently, these findings suggest that the Cry1Ia36 protein could be a promising nematicidal agent for the control of PPN diseases, which offers a viable alternative to chemical pesticides because of its association with environmental concerns, although no previous reports have been found that demonstrate its activity against PPNs. Concurrently, this study has also expanded the spectrum of Bt ICPs.