Expression of a cysteine proteinase inhibitor (oryzacystatin-I) in transgenic tobacco plants

• Published in: Plant molecular biology 1993-02, Vol.21 (4), p.655-663
• Main Authors: Masoud, S.A. (Kansas State Univ., Manhattan, KS (USA). Dept. of Biochemistry), Johnson, L.B, White, F.F, Reeck, G.R
• Format: Article
• Language: English
• Subjects: AGROBACTERIUM TUMEFACIENS; Biological and medical sciences; Biotechnology; Cystatins - genetics; Cystatins - isolation & purification; Cystatins - metabolism; DNA - genetics; DNA, Recombinant - analysis; EXPRESION GENICA; EXPRESSION DES GENES; Fundamental and applied biological sciences. Psychology; GENE EXPRESSION; Genetic engineering; Genetic technics; GENETIC TRANSFORMATION; Methods. Procedures. Technologies; Modification of gene expression level; Nicotiana; NICOTIANA TABACUM; Oryza - enzymology; Plants, Genetically Modified; Plants, Toxic; Recombinant Proteins - metabolism; RNA, Messenger - genetics; TRANSFORMACION GENETICA; TRANSFORMATION GENETIQUE
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/bf00014548

Expression of cysteine proteinase inhibitors (cystatins) in tobacco or other plants has the potential for improving resistance against pathogens and insects that possess cysteine proteinases. A chimeric gene containing a cDNA clone of rice cystatin (oryzacystatin-I; OC-I), the cauliflower mosaic virus 35S promoter, and the nopaline synthase 3' region was introduced into tobacco plants by Agrobacterium tumefaciens. The presence of the chimeric gene in transgenic plants was detected by a polymerase chain reaction-amplified assay, and transcriptional activity was shown by RNA blot analysis. Heated extracts from transgenic tobacco plants, as well as from progeny which were obtained by selfing a primary transformant, contained protein bands that corresponded in molecular mass to OC-I and reacted with antibodies raised against rOC, a recombinant OC-I protein produced by Escherichia coli. Similar bands were absent in extracts from untransformed control plants. OC-I levels reached 0.5% and 0.6% of the total soluble proteins in leaves and roots, respectively, of some progeny. On a fresh weight basis, the OC-I content was higher in leaves (50 micrograms/g) than in roots (30 micrograms/g). OC-I was partially purified from protein extracts of rice seeds and from transgenic tobacco leaves by affinity to anti-rOC antibodies. OC-I from both sources was active against papain.