Contents - Faperta

Genetic Transformation of Crops for Resistance to Insect Pests 233
larvae fed on transformed plants of tobacco expressing the protein Tarin 1 from Colocasia
esculenta (L.) Schott. exhibited retarded growth, and reduced pupation and biomass, and
increased larval mortality (Leal Bertioli et al., 2003). Tarin 1 also inhibited the growth of
Pseudomonas syringae van Hall (pv. tomato) under in vitro conditions. Root damage by
Meloidogyne javanica (Treub.) was greater in the control plants than in the transformed
plants, but the results were not statistically signifi cant (Leal Bertioli et al., 2003).
Potato
Transgenic potatoes expressing GNA and concanavalin A (ConA) were less susceptible to
peach-potato aphid, M. persicae (Gatehouse et al., 1995, 1996, 1999). Larval biomass of the
tomato moth, Lecanobia oleracea (L.) is reduced in artifi cial diet containing GNA, and on
excised leaves of transgenic tomato (Fitches, Gatehouse, and Gatehouse, 1997), which may
result in lower fecundity of the female moths. Accumulation of the transgene product in
transformed potato plants expressing GNA increased as the potato plant developed, with
maximum levels found in mature plants (Down et al., 2001). The variation in accumulation
of GNA in transgenic plants within a line of clonal replicates was correlated with expression
of resistance to the larvae of tomato moth, L. oleracea. Growing conditions affected the
levels of GNA expression in transgenic plants and the expression of resistance to L. oleracea
(Down et al., 2001).
Cotton
Larvae of cotton budworm, H. virescens, fed on transformed cotton with the lectin gene
have a reduced weight, but there was no effect on larval survival (Satyendra, Stewart, and
Wilkins, 1998).
Cereals
Transgenic maize expressing wheat agglutinin has shown moderate activity against
O. nubilalis and Diabrotica sp. (Maddock et al., 1991). Snowdrop lectin at levels greater than
0.04% decreases the fecundity but not the survival of the grain aphid, Sitobion avenae (F.)
(Stoger et al., 1999). Transgenic haploid rice shoots with GNA have shown resistance to
brown planthopper, N. lugens, green planthopper, Nephotettix virescens (Distant) (C.D. Yang
et al., 1998; Tinjuangjun et al., 2000; Tang et al., 2001), rice small brown planthopper,
Laodelphax striatellus (Fallen) (Sun, Wu, and Tang, 2002), and potato leafhoppers, Empoasca
fabae (Harris) (Habibi, Backus, and Czapla, 1992). In plants where GNA expression is
tissue-specifi c (phloem and epidermal layer), or constitutive, the green planthopper
survival has been reduced by 23 and 53%, respectively (Foissac et al., 2000). The brown
planthopper nymphs tended to avoid plants expressing GNA, and avoidance was less pronounced
and took a longer time to develop on plants where GNA expression was tissue
specifi c. In contrast to brown planthopper, the green planthopper nymphs were attracted
to plants expressing GNA.
Sugarcane
Transgenic sugarcane plants engineered to express GNA have shown increased antibiosis to
larvae of sugarcane grubs, A. consanguineus (Nutt et al., 1999). Larvae feeding on the roots of
transgenic sugarcane plants gained only 20.6% of the weight of controls (Nutt et al., 2001).