biologia plantarum

Biologia plantarum 50:793-796, 2006 | DOI: 10.1007/s10535-006-0134-x

Stress-induced changes in the free amino acid composition in transgenic soybean plants having increased proline content

L. Simon-Sarkadi^1,*, G. Kocsy², Á. Várhegyi¹, G. Galiba², J. A. De Ronde³

¹ Department of Biochemistry and Food Technology, Budapest University of Technology and Economics, Budapest, Hungary

² Agricultural Research Institute of the Hungarian Academy of Sciences, Martonvásár, Hungary

³ Roodeplaat Vegetable and Ornamental Plant Institute, Private Bag X293, Pretoria, South Africa

Following drought stress at supraoptimal temperature the increase in proline (Pro) content in transgenic (T) soybean [Glycine max (L.) Merr. cv. Ibis] plants overexpressing the gene coding for the last enzyme of Pro biosynthesis, L-Δ¹-pyrroline-5-carboxylate reductase, was much greater than in wild type (W) plants (105-fold versus 19-fold after 7 d). Under control conditions arginine accounted for nearly 60 % of the total free amino acid content. After stress treatment the content of Pro was more than 50 % in both T and W genotypes, and at the end of recovery the γ-aminobutyrate content reached 27 and 53 % in the W and T plants, respectively. Without stress treatment there was only a 2-fold difference between T and W in the tyrosine content. However, during the stress period and the subsequent recovery a similar difference was found for many amino acids. The present results indicate that manipulating of the content of a single amino acid influences the whole free amino acid composition in soybean.

Keywords: drought; Glycine max; heat

Subjects: amino acids; 3,6-dichloro-o-anisic acid; drought stress; proline; Δ¹-pyrroline-5-carboxylate reductase; relative water content (RWC); soybean; temperature, high, stress; transgenic plants (cf. also in vitro…)

Received: May 3, 2005; Accepted: September 15, 2005; Published: December 1, 2006  Show citation