Assessment of conditions affecting Agrobacterium-mediated soybean transformation using the cotyledonary node explant

• Published in: Euphytica Vol. 136; no. 2; pp. 167 - 179
• Main Authors: Paz, M.M, Shou, H, Guo, Z, Zhang, Z, Banerjee, A.K, Wang, K
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 2004
• Subjects: Agrobacterium; Agrobacterium tumefaciens; Agronomy. Soil science and plant productions; bar gene; bilanafos; Biological and medical sciences; chlorine; cotyledons; cultivars; culture media; cysteine; dithiothreitol; explants; Fundamental and applied biological sciences. Psychology; gene transfer; genetic transformation; Genetics and breeding of economic plants; glufosinate; Glycine max; herbicide resistance; in vitro regeneration; phosphinothricin acetyltransferase; seed germination; seed vigor; seeds; shoots; soybeans; sterilizing; transgenes; transgenic plants; Cotyledon; Node; cysteine; Explant; Agrobacterium tumefaciens; Soybean; transformation; Glycine max; Agrobacterium; Leguminosae; Dicotyledones; Angiospermae; Genetic improvement; Bacteria; glufosinate; Spermatophyta; Rhizobiaceae
• ISSN: 0014-2336; 1573-5060
• DOI: 10.1023/b:euph.0000030670.36730.a4

Conditions affecting Agrobacterium-mediated transformation of soybean [Glycine max (L.) Merr.], including seed vigor of explant source, selection system, and cocultivation conditions, were investigated. A negative correlation between seed sterilization duration and seed vigor, and a positive correlation between seed vigor and regenerability of explants were observed in the study, suggesting that use of high vigor seed and minimum seed sterilization duration can further improve transformation efficiency. Selection schemes using glufosinate or bialaphos as selective agents in vitro were assessed. Glufosinate selection enhanced soybean transformation as compared to bialaphos. The use of 6 mg L super(-1) glufosinate during shoot induction and shoot elongation stages yielded higher final transformation efficiency ranging from 2.0% to 6.3% while bialaphos at 4 to 6 mg L super(-1) gave 0% to 2.1% efficiency. Including cysteine and DTT during cocultivation increased the transformation efficiency from 0.2-0.9% to 0.6-2.9%. This treatment also improved T-DNA transfer as indicated by enhanced transient GUS expression. Shoot regeneration and Agrobacterium infection were attained in twelve soybean cultivars belonging to maturity groups I-VI. These cultivars may be amenable to genetic transformation and may provide a valuable tool in soybean improvement programs.