A fusion protein containing a lepidopteran-specific toxin from the South Indian red scorpion (Mesobuthus tamulus) and snowdrop lectin shows oral toxicity to target insects.

Background: Despite evidence suggesting a role in plant defence, the use of plant lectins in crop protection has been hindered by their low and species-specific insecticidal activity. Snowdrop lectin (Galanthus nivalis agglutinin; GNA) is transported to the haemolymph of insects after oral ingestion, and can be used as a basis for novel insecticides. Recombinant proteins containing GNA expressed as a fusion with a peptide or protein, normally only toxic when injected into the insect haemolymph, have the potential to show oral toxicity as a result of GNA-mediated uptake.

An alternative strategy for sustainable pest resistance in genetically enhanced crops.

Bacillus thuringiensis (Bt) crystal protein genes encode insecticidal delta-endotoxins that are widely used for the development of insect-resistant crops. In this article, we describe an alternative transgenic strategy that has the potential to generate broader and more sustainable levels of resistance against insect pests. Our strategy involves engineering plants with a fusion protein combining the delta-endotoxin Cry1Ac with the galactose-binding domain of the nontoxic ricin B-chain (RB).

Reduction in the endogenous arginine decarboxylase transcript levels in rice leads to depletion of the putrescine and spermidine pools with no concomitant changes in the expression of downstream genes in the polyamine biosynthetic pathway.

We investigated whether down-regulation of arginine decarboxylase (ADC) activity and concomitant changes in polyamine levels result in changes in the expression of downstream genes in the polyamine pathway. We generated transgenic rice (Oryza sativa L.) plants in which the rice adc gene was down-regulated by expression of its antisense oat (Avena sativa L.

Expression of a heterologous S-adenosylmethionine decarboxylase cDNA in plants demonstrates that changes in S-adenosyl-L-methionine decarboxylase activity determine levels of the higher polyamines spermidine and spermine.

We posed the question of whether steady-state levels of the higher polyamines spermidine and spermine in plants can be influenced by overexpression of a heterologous cDNA involved in the later steps of the pathway, in the absence of any further manipulation of the two synthases that are also involved in their biosynthesis. Transgenic rice (Oryza sativa) plants engineered with the heterologous Datura stramonium S-adenosylmethionine decarboxylase (samdc) cDNA exhibited accumulation of the transgene steady-state mRNA. Transgene expression did not affect expression of the orthologous samdc gene.