Embrapa Recursos Genéticos e Biotecnologia, PqEB W5 Norte, 70770-900, Brasília, DF, Brazil.
Universidade de Brasília, Departamento de Biologia Celular, Campus Universitário, 70910-900, Brasília, DF, Brazil.
Sci Rep. 2017 Nov 13;7(1):15385. doi: 10.1038/s41598-017-15636-7.
Ricin is a highly toxic ribosome-inactivating lectin occurring in the seeds of castor bean (Ricinus communis L.). Castor bean grows throughout tropical and sub-tropical regions and is a very important crop due to its high seed content of ricinoleic acid, an unusual fatty acid, which has several industrial applications. However, due to the presence of the toxin, castor bean can cause death after the exposure of animals to low doses of ricin through skin contact, injection, inhalation or oral routes. Aiming to generate a detoxified genotype, we explored the RNAi concept in order to silence the ricin coding genes in the endosperm of castor bean seeds. Results indicated that ricin genes were effectively silenced in genetically modified (GM) plants, and ricin proteins were not detected by ELISA. Hemagglutination activity was not observed with proteins isolated from GM seeds. In addition, we demonstrated that seed proteins from GM plants were not toxic to rat intestine epithelial cells or to Swiss Webster mice. After oil extraction, bio-detoxified castor bean cake, which is very rich in valuable proteins, can be used for animal feeding. Gene silencing would make castor bean cultivation safer for farmers, industrial workers and society.
蓖麻毒素是一种存在于蓖麻（Ricinus communis L.）种子中的高度毒性核糖体失活凝集素。蓖麻生长在热带和亚热带地区，由于其种子中含有高浓度的蓖麻酸，这是一种不寻常的脂肪酸，具有多种工业应用，因此是一种非常重要的作物。然而，由于毒素的存在，动物通过皮肤接触、注射、吸入或口服途径接触低剂量的蓖麻毒素后会导致死亡。为了产生解毒基因型，我们探索了 RNAi 概念，以便在蓖麻种子的胚乳中沉默蓖麻毒素编码基因。结果表明，在转基因（GM）植物中有效沉默了蓖麻基因，ELISA 检测不到蓖麻蛋白。从 GM 种子中分离出的蛋白质没有观察到血凝活性。此外，我们证明了来自 GM 植物的种子蛋白对大鼠肠上皮细胞或瑞士 Webster 小鼠没有毒性。油提取后，富含有价值蛋白质的生物解毒蓖麻饼可用于动物饲养。基因沉默将使蓖麻种植对农民、工业工人和社会更安全。
