Soybeans are the main source of oils and protein for humans and animals; however, cold stress jeopardizes their growth and limits the soybean planting area. Aldehyde dehydrogenases (ALDH) are conserved enzymes that catalyze aldehyde oxidation for detoxification in response to stress. Additionally, transgenic breeding is an efficient method for producing stress-resistant germplasms. In this study, the peanut ALDH gene AhALDH2B6 was heterologously expressed in soybean, and its function was tested. We performed RNA-seq using transgenic and wild-type soybeans with and without cold treatment to investigate the potential mechanism. Transgenic soybeans developed stronger cold tolerance, with longer roots and taller stems than P3 soybeans. Biochemically, the transgenic soybeans exhibited a decrease in malondialdehyde activity and an increase in peroxidase and catalase content, both of which are indicative of stress alleviation. They also possessed higher levels of ALDH enzyme activity. Two phenylpropanoid-related pathways were specifically enriched in up-regulated differentially expressed genes (DEGs), including the phenylpropanoid metabolic process and phenylpropanoid biosynthetic process. Our findings suggest that AhALDH2B6 specifically up-regulates genes involved in oxidoreductase-related functions such as peroxidase, oxidoreductase, monooxygenase, and antioxidant activity, which is partially consistent with our biochemical data. These findings established the function of AhALDH2B6, especially its role in cold stress processes, and provided a foundation for molecular plant breeding, especially plant-stress-resistance breeding.

Soybean [Glycine max (L.) Merr.], an essential staple food and oil crop worldwide, boasts abundant vegetable proteins and fats beneficial for both human and animal consumption. However, the soybean pod borer (Leguminivora glycinivorella) (SPB) stands as the most destructive soybean insect pest in northeast China and other northeastern Asian regions, leading to significant annual losses in soybean yield and economic burden. Therefore, this study aims to investigate the introduction of a previously tested codon-optimized cry1c gene, cry1c*, into the soybean genome and assess its effect on the SPB infestation by generating and characterizing stable transgenic soybeans overexpressing cry1c*. The transgenic soybean lines that constitutively overexpressed cry1c* exhibited a significant reduction in the percentage of damaged seeds, reaching as low as 5% in plants under field conditions. Additionally, feeding transgenic leaves to the larvae of S. exigua, S. litura, and M. separta resulted in inhibited larval growth, decreased larval body weight, and lower survival rates compared to larvae fed on wild-type leaves. These findings showed that the transgenic lines maintained their resistance to SPB and other lepidopteran pests, especially the transgenic line KC1. Southern blotting and genome-wide resequencing analysis revealed that T-DNA integration occurred as a single copy between loci 50,868,122 and 50,868,123 of chromosome 10 in the transgenic line KC1. Therefore, the transgenic line KC1, overexpressing high levels of cry1c* in leaves and seeds, holds strong potential for commercial use in the integrated management of SPB and other lepidopteran pests.