Enhanced Resistance of Snowdrop Lectin （Galanthus nivalis L. agglutinin） Expressing Maize to Asian Corn Borer （Ostriniafurnacalis Guenée）

In order to enhance the resistance to pests, transgenic maize (Zea mays L.) plants from elite inbred lines containing the gene encoding snowdrop lectin (Galanthus nivalis L. agglutinin; GNA) under control of a phloem-specific promoter were generated through the Agrobacterium tumefaciens-mediated also studied. Thirty-six independently derived plants were subjected to molecular analyses. The level of GNA expression at 0.13%-0.28% of total soluble protein was observed in different transgenic plants. The progeny of three GNA-expressing independent transformants that were derived separately from the elite inbred lines DH4866, DH9942, and 8902, were selected for examination of resistance to ACB. These plants synthesized GNA at levels above 0.24% total soluble protein and enhanced resistance to ACB was demonstrated by exposing the plants to insects under greenhouse conditions. Semi-artificial diet bioassays also showed the toxic effect of GNA on ACB. Field evaluation of the transgenic plants supported the results from the artificial trial. In the present study, we have obtained new insect-resistant maize material for further breeding work and have found that GNA-expressing plants not only gained significant resistance to homopterans, but also showed toxicity to ACB, which is a type of Lepidoptera.

Study on the Obtaining of Transgenic Wheat with GNA Alien Gene by Biolistic Particle

The immature embryos of wheat plants, cv. Jing 411, 12 - 14 days after pollination, were cultured on SD2 medium for callus induction. After 10 days culture, 800 wheat calli were bombarded by biolistic particle coated with the DNA of plasmid pBI121-2 harboring both Galanthus nivalis agglutinin gene and bar gene. 67 green plants were finally regenerated from the bombardment calli on selection medium containing 4mg/L Basta. The results of bioassay by both inoculating wheat aphids onto the plants and applying Basta solution of 50 mg/L and 75 mg/L onto the wheat leaves in the field, and the molecular analysis, such as PCR and Southern blotting, indicated that 8 T2 plants contaning the target genes were obtained.

Ferritin acts as a target site for the snowdrop lectin （GNA） in the midgut of the cotton leafworm Spodoptera littoralis

The snowdrop lectin GNA （Galanthus nivalis agglutinin） has been shown to possess insecticidal activity to a range of economically important insect pests. However, the precise mechanism of insecticidal action of GNA against insects remains unknown. In this investigation, we attempted to purify and identify receptor（s） responsible for binding of GNA in the larval midgut of a major lepidopteran pest （the cotton leafworm, Spodoptera littoralis） to better understand its mode of action. Therefore, cytoplasmic as well as membrane proteins from 800 larval midguts were chromatographed on a column with immobilized GNA. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the proteins eluted from the GNA column followed by sequencing of the GNA-binding proteins and BLAST analyses revealed that the N-terminal sequences of a 24 kDa polypeptide purified from the cytoplasmic and membrane protein fraction revealed sequence similarity to sequences encoding heavy chain homologs of ferritin from Manduca sexta （76% sequence identity）, Calpodes ethlius （80% sequence identity） and Bombyx mori （61% sequence identity）. Furthermore, the N-terminal sequence of a 31 kDa polypeptide from the membrane protein fraction showed sequence similarity to a light chain homolog of ferritin from Manduca sexta （88% sequence identity）.