Artificial Synthetic Snow Nivalis Agglutinin (gna) Gene Expression In Transgenic Wheat And The Effect Of Resistance To Aphids

Wheat is one of the most abundant sources of energy and protein for the world population. In China, wheat production also play important role in feeding millions of people. With the improvement of irrigation conditions on cornfield and changes of agricultural ecosystem, wheat aphid cause more losses than ever in wheat productivity. Nowadays, pest control and management heavily count on many chemical pesticides, however, the indiscriminate use of pesticides are toxic to beneficial insects, which act as predators or parasites to the pest species, and have a harmful effect on natural environment. Screening and identifying varieties that possess pest-resistant trait are main breeding objects of wheat, but the progress has been slow and difficult to achieve by conventional breeding means, due to host-plant resistance to insects involving quantitative traits at several loci. Therefore, seeking effective approaches to enchace wheat resistance against pest attack are necessary.With the advancement of modern biotechnoloigy, molecular breeding place brand new hopes on human's crop cultivation. The gene of δ - endotoxins from Bacillus thuringiensis (Bt), protease inhibitors gene, plant lectin genes had been cloned and demostrate insect resistance in transgenic plants; genetic transformation of wheat by particle bombardment procedure was well established over past decade and introduction of entirely novel resistance genes to wheat by genetic engineering becames possible.Galanthus navalis agglutinin (GNA) from the bulb of sonowdrop of Amaryllidaceae has great resistance to Homoptera sap-sucking pests including wheat aphid, rice brown planthopper, by inhibiting their growth and fecundity, furthermore, GNA is nontoxic to higher animals or predators to pest. Snowdrop lectin is currently receiving most interest as insecticidal agents against homopteran plant pests and might be suitable in the control of wheat aphid damage through genetic modification.In this study, an expression vector pBAC202 containing a synthesized gene encoding snowdrop lectin (Galanthus nivalis agglutinin, GNA) driven by small subunit of ribulose bisphosphate carboxylase gene (RbcS) promoter was constructed and then transferred into indigenous high yield wheat cultivars explants of immature inflorescence and immature embryos by particle bombardment method. Forty-two transformed plants were produced. DNA dot blotting, PCR and PCR-Southern hybridization analysis were performed and the exogenous gene integration was confirmed. Protein extracted from leaf of transgenic plants were subjected to red blood cell agglutination bioassay; the experimental result showed that the selected transformants had expressed GNA with normal biological functions. The aphid (Rhopalosiphum padi) resistance bioassay were carried out under artificial condition; the aphid reduction rate in different transgene lines ranges from 19% to 73%, the average reduction rate is 47% based on statistic data and some transgenic lines demonstrated strong...