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.

Background: Soybean oil is a complex mixture of five fatty acids (palmitic, stearic, oleic, linoleic, and linolenic). Soybean oil with a high oleic acid content is desirable because this monounsaturated fatty acid improves the oxidative stability of the oil. To investigate the genetic architecture of oleic acid in soybean seeds, 260 soybean germplasms from Northeast China were collected as natural populations. A genome-wide association study (GWAS) was conducted on a panel of 260 germplasm resources. Results: Phenotypic identification results showed that the oleic acid content varied from 8.2 to 35.0%. A total of 2,311,337 single-nucleotide polymorphism (SNP) markers were obtained. GWAS analysis showed that there were many genes related to oleic acid content with a contribution rate of 7%. The candidate genes Glyma.11G229600.1 on chromosome 11 and Glyma.04G102900.1 on chromosome 4 were detected in a 2-year-long GWAS. The candidate gene Glyma.11G229600.1 showed a positive correlation with the oleic acid content, and the correlation coefficient was 0.980, while Glyma.04G102900.1 showed a negative correlation, with a coefficient of − 0.964. Conclusions: Glyma.04G102900.1 on chromosome 4 and Glyma.11G229600.1 on chromosome 11 were detected in both analyses (2018 and 2019). Glyma.04G102900.1 and Glyma.11G229600.1 are new key candidate genes related to oleic acid in soybean seeds. These results will be useful for high-oleic soybean breeding.

Background: Soybeans [Glycine max (L.) Merr] originated in China and has been cultivated for more than 3000 years. Soybean oil is a complex mixture of five fatty acids (palmitic, stearic, oleic, linoleic, and linolenic). Soybean oil with high oleic acid content is desirable because this monounsaturated fatty acid improves the oxidative stability of the oil. To investigate the genetic architecture of oleic acid in soybean seed. 260 Soybean germplasms from Northeast China were collected as the natural population. A genome-wide association study (GWAS) was conducted in a panel of 260 germplasm resources.Results: Phenotypic identification result showed that the content of oleic acid varied from 8.2% to 35.0%. 2,311,337 single nucleotide polymorphism (SNP) markers were obtained. GWAS analysis showed that there were many genes related to oleic acid content with contribution rate 7%. The candidate genes Glyma.11G229600.1 on chromosome 11 and Glyma.04G102900.1 on chromosome 4 were detected in a 2-year long GWAS. The candidate gene Glyma.11G229600.1 showed a positive correlation with the oleic acid content, and the correlation coefficient was 0.980, while Glyma.04G102900.1 showed a negative correlation with the oleic acid content. The correlation coefficient was -0.964.Conclusions: Glyma.04G102900.1 on chromosome 4 and Glyma.11G229600.1 on chromosome 11 were detected in both anaylsis (2018 and 2019). Glyma.04G102900.1 and Glyma.11G229600.1 are new key candidate genes related to oleic acid in soybean seeds.These results will be useful for High-oleic soybean breeding.