Transgenic rice established to express corn cystatin exhibits strong inhibitory activity against insect gut proteinases

• Published in: Plant molecular biology Vol. 30; no. 1; pp. 149 - 157
• Main Authors: Irie, K, Hosoyama, H, Takeuchi, T, Iwabuchi, K, Watanabe, H, Abe, M, Abe, K, Arai, S
• Format: Journal Article
• Language: English
• Published: Netherlands 1996
• Subjects: Animals; Base Sequence; cathepsins; Coleoptera; Coleoptera - enzymology; complementary DNA; Cystatins - biosynthesis; Cystatins - genetics; Cysteine Proteinase Inhibitors - biosynthesis; Cysteine Proteinase Inhibitors - genetics; Digestive System - enzymology; Dose-Response Relationship, Drug; enzyme activity; gene expression; gene transfer; Genes, Plant; immunohistochemistry; inhibition; leaves; messenger RNA; midgut; midgut proteinases; Molecular Sequence Data; Oryza - genetics; Oryza sativa; papain; plant proteins; Plants, Genetically Modified; proteinase inhibitors; RNA, Messenger - biosynthesis; RNA, Plant - biosynthesis; Sitophilus; Sitophilus zeamais; Tissue Distribution; transgenic plants; Zea mays; Zea mays - enzymology; Zea mays - genetics
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/bf00017809

Corn cystatin (CC), a phytocystatin, shows a wide inhibitory spectrum against various cysteine proteinases. We produced transgenic rice plants by introducing CC cDNA under CaMV 35S promoter as a first step to obtain a rice plant with insecticidal activity. This attempt was based on the observation that many insect pests, especially Coleoptera, have cysteine proteinases, probably digestive enzymes, and also that oryzacystatin, an intrinsic rice cystatin, shows a narrow inhibition spectrum and is present in ordinary rice seeds in insufficient amounts to inhibit the cysteine proteinases of rice insect pests. The transgenic rice plants generated contained high levels of CC mRNA and CC protein in both seeds and leaves, the CC protein content of the seed reaching ca. 2% of the total heat soluble protein. We also recovered CC activity from seeds and found that the CC fraction efficiently inhibited both papain and cathepsin H, whereas the corresponding fraction from non-transformed rice seeds showed much lower or undetectable inhibitory activities against these cysteine proteinases. Furthermore, CC prepared from transgenic rice plants showed potent inhibitory activity against proteinases that occur in the gut of the insect pest, Sitophilus zeamais.