Soybean (Glycine max), a key food and oilseed crop, is derived from wild soybean (Glycine soja). Compared with cultivated varieties, wild soybean exhibits significantly higher genetic diversity, harboring stress-tolerance genes, broad-spectrum disease-resistance genes, and superior alleles that regulate seed nutrition, which were lost during domestication. These genetic resources have remained “visible yet underutilized”, primarily due to the lack of mature transformation and gene editing systems. In this study, we established stable genetic transformation and gene editing systems for Glycine soja. We identified three major bottlenecks to the genetic transformation of Glycine soja: its thick, rigid seed coat impairs water absorption and germination; its Agrobacterium infection efficiency is low; and regenerated shoots exhibit severe chlorosis and death. To address these issues, we employed 1) seed coat sandpaper abrasion enables wild soybean seeds to absorb water and germinate within 1 d; 2) sonication at 45 kHz for 60 s, which increased the Agrobacterium infection rate from 11.76% to 55.26%; and 3) supplementation of the culture media with an additional 12 mg L⁻¹ ferrous sulfate and 30 mg L⁻¹ disodium ethylenediaminetetraacetic acid (EDTA), which alleviated chlorosis in regenerated shoots. The transformation efficiencies of two wild soybean accessions reached 1.54% and 6.33%, with stable transgene heritability. We targeted GsDELLA and successfully generated homozygous mutants, which displayed reduced plant height and branch number. We extended this approach to 19 elite soybean cultivars, obtaining positive transformants, with higher transformation efficiencies for late-maturing (MG I–VI; typically > 10%) than early-maturing (MG 00–I; 2%–10%) varieties. Our versatile transformation platform should accelerate the genetic improvement of both wild and cultivated soybean germplasm.

A fast and efficient recognition method of transgenic lines will greatly improve detection efficiency and reduce cost. In this study, we successfully identified the transgenic soybean plants by the color. We isolated a GmW1 gene encoding a flavonoid 3′5′-hydroxylase from a soybean cultivar ZH42 (purple flower). We found that purple flowers occurred in the overexpression lines in the Jack and Williams 82 backgrounds (white flower). All plants with purple flowers were positive, and this trait seems stably inherited in the offspring. We have also obtained the editing plants, which were classified into three types according to the different flower colors appeared. We analyzed the phenotype and the homozygous types of the T₁ mutants. We also found that a correspondence between flower color and stem color. This study provides a visible color reporter on soybean transformation. It can be quickly and early to identify the transgenic soybean plants by stem color of seedlings, which substantially reduces the amount of labor and cost.

Soybean is one of the world's most important oil and protein crops. Efficient transformation is a key factor for the improvement of soybean by genetic modification. We describe an optimized protocol for the Agrobacterium rhizogenes-mediated transformation of soybean and the induction of hairy root development in vitro. Cotyledons with 0.5-cm hypocotyls were cut from 5-day-old seedlings and used as explants. After infection and co-cultivation, hairy roots were produced in induction culture medium after 10–12days. Using this method, 90%–99% of the infected explants of five different cultivars produced hairy roots within one month. Observations using reporter constructs showed that 30%–60% of the hairy roots induced were transformed. Based on high transformation efficiency and short transformation period, this method represents an efficient and rapid platform for study of soybean gene function.