Yarasi Bharathi, Sadumpati Vijayakumar, Immanni China Pasalu, Vudem Dasavantha Reddy, Khareedu Venkateswara Rao
Centre for Plant Molecular Biology, Osmania University, Hyderabad, 500 007, India.
BMC Plant Biol. 2008 Oct 14;8:102. doi: 10.1186/1471-2229-8-102.
Rice (Oryza sativa) productivity is adversely impacted by numerous biotic and abiotic factors. An approximate 52% of the global production of rice is lost annually owing to the damage caused by biotic factors, of which approximately 21% is attributed to the attack of insect pests. In this paper we report the isolation, cloning and characterization of Allium sativum leaf agglutinin (asal) gene, and its expression in elite indica rice cultivars using Agrobacterium-mediated genetic transformation method. The stable transgenic lines, expressing ASAL, showed explicit resistance against major sap-sucking pests.
Allium sativum leaf lectin gene (asal), coding for mannose binding homodimeric protein (ASAL) from garlic plants, has been isolated and introduced into elite indica rice cultivars susceptible to sap-sucking insects, viz., brown planthopper (BPH), green leafhopper (GLH) and whitebacked planthopper (WBPH). Embryogenic calli of rice were co-cultivated with Agrobacterium harbouring pSB111 super-binary vector comprising garlic lectin gene asal along with the herbicide resistance gene bar, both under the control of CaMV35S promoter. PCR and Southern blot analyses confirmed stable integration of transgenes into the genomes of rice plants. Northern and western blot analyses revealed expression of ASAL in different transgenic rice lines. In primary transformants, the level of ASAL protein, as estimated by enzyme-linked immunosorbent assay, varied between 0.74% and 1.45% of the total soluble proteins. In planta insect bioassays on transgenic rice lines revealed potent entomotoxic effects of ASAL on BPH, GLH and WBPH insects, as evidenced by significant decreases in the survival, development and fecundity of the insects.
In planta insect bioassays were carried out on asal transgenic rice lines employing standard screening techniques followed in conventional breeding for selection of insect resistant plants. The ASAL expressing rice plants, bestowed with high entomotoxic effects, imparted appreciable resistance against three major sap-sucking insects. Our results amply demonstrate that transgenic indica rice harbouring asal exhibit surpassing resistance against BPH, GLH and WBPH insects. The prototypic asal transgenic rice lines appear promising for direct commercial cultivation besides serving as a potential genetic resource in recombination breeding.
水稻（Oryza sativa）的生产力受到多种生物和非生物因素的不利影响。由于生物因素造成的损害，全球每年约52%的水稻产量损失，其中约21%归因于害虫的侵袭。在本文中，我们报告了大蒜叶凝集素（asal）基因的分离、克隆和特性分析，以及利用农杆菌介导的遗传转化方法在优良籼稻品种中的表达。表达ASAL的稳定转基因系对主要的刺吸式害虫表现出明显的抗性。
大蒜叶凝集素基因（asal）编码来自大蒜植株的甘露糖结合同型二聚体蛋白（ASAL），已被分离并导入对刺吸式昆虫敏感的优良籼稻品种，即褐飞虱（BPH）、绿叶蝉（GLH）和白背飞虱（WBPH）。水稻胚性愈伤组织与携带pSB111超双元载体的农杆菌共培养，该载体包含大蒜凝集素基因asal以及除草剂抗性基因bar，两者均受CaMV35S启动子控制。PCR和Southern杂交分析证实转基因已稳定整合到水稻植株的基因组中。Northern和western杂交分析揭示了ASAL在不同转基因水稻系中的表达。在初级转化体中，通过酶联免疫吸附测定法估计，ASAL蛋白水平占总可溶性蛋白的0.
