Di Qin, Xiao-Yi Liu, Cristina Miceli, Qi Zhang & Pi-wu Wang

BMC Biotechnology volume 19, Article number: 66 (2019); Published: 15 October 2019

Abstract

Background

Cry8-like from Bacillus thuringiensis (Bt) encodes an insecticidal crystal (Cry) protein. Holotrichia parallela (Coleoptera: Scarabaeoidae), commonly known as the dark black chafer, is a troublesome pest of soybean (Glycine max). To test whether cry8-like can confer resistance against H. parallela to soybean, we introduced cry8-like from the Bt strain HBF-18 into soybean cultivar Jinong 28.

Results

Quantitative reverse transcription-PCR analysis demonstrated that cry8-like was expressed most highly in soybean leaves. In addition, Southern blot assays revealed that one copy of the integrated fragment was present in the transformed plants. Eight independent cry8-like transgenic lines were subsequently fed on by H. parallela. Under H. parallela feeding stress, the survival rates of the non-transgenic plants were 92% lower than those of the transgenic plants. The mortality rate of H. parallela increased when the larvae fed on the roots of T₁ transgenic soybean plants. Moreover, the surviving larvae were deformed, and their growth was inhibited.

Conclusions

Collectively, our data suggest that transgenic soybean plants expressing the cry8-like gene are more resistant to H. parallela than non-transgenic plants and that transgenic expression of the cry8-like gene may represent a promising strategy for engineering pest tolerance. The events generated in this study could thus be utilized in soybean breeding programs.

See https://bmcbiotechnol.biomedcentral.com/articles/10.1186/s12896-019-0563-1

Figure 2: Agrobacterium-mediated transformation of soybean. (a) Diagram of pCAMBIA3300-cry8-like used for transformation. (b) Soybean cotyledon nodes cultured on shoot-induction medium (c) and (d) Shoot development. (e) 3-month-old T₀ transgenic soybean plants grown under greenhouse conditions in soil