Contents - Faperta

Genetic Transformation of Crops for Resistance to Insect Pests 229
Rice
Expression of the potato trypsin inhibitor gene confers resistance to insect pests in rice
(Duan et al., 1996). Constitutive expression of CpTi increases resistance to C. suppressalis
and Sesamia inferens (Walker) in rice (Xu et al., 1996). A synthetic gene (mwti11b) coding for
a winged bean trypsin inhibitor (WTI-11B) signifi cantly retarded the larval growth of
C. suppressalis in rice (Mochizuki et al., 1999). Accumulation of Kunitz type SBTI in rice also
confers resistance to the brown planthopper, Nilaparvata lugens (Stal) (Lee et al., 1999).
Wheat
The Angoumois grain moth, Sitotroga cerealella (Oliver), is one of the major storage pests of
cereals, and no antibiotic resistance in wheat against this insect has been identifi ed to date.
Characterization of the midgut proteases of S. cerealella larvae revealed that the major
digestive proteases were trypsin-like and alpha-chymotrypsin-like serine proteases
(Shukle and Wu, 2003). The potential value of naturally occurring plant protease inhibitors
as resistance factors for S. cerealella has been assessed in bioassays using artifi cial seeds
prepared by freeze-drying a fl our paste in Tefl on moulds and then coating the seeds with
gelatin. Soybean trypsin inhibitor (Kunitz inhibitor) had an adverse effect on the development
of the insect and suggested that protease inhibitors might serve as a transgenic
resistance factor (Shukle and Wu, 2003). A signifi cant reduction in survival rate of the
Angoumois grain moth, S. cerealella has been observed on transgenic wheat seeds expressing
the trypsin inhibitor from barley (Altpeter et al., 1999). However, it did not have a
signifi cant protective effect against leaf-feeding insects.
Sugarcane
Transgenic sugarcane plants expressing potato proteinase inhibitor II have shown
increased antibiosis to larvae of sugarcane grubs, Antitrogus consanguineus (Blackburn)
(Nutt et al., 1999). Antitrogus consanguineus larvae feeding for six weeks on transgenic
plants carrying the potato proteinase inhibitor II gene gained only 4.2% of the weight of
grubs feeding on nontransgenic control plants (Nutt et al., 2001).
Vegetables
The CpTi gene in cabbage, B. oleracea var capitata (cultivars Yingchun and Jingfeng), has
shown resistance to P. rapae (Fang et al., 1997). However, adults of Psylliodes chrysocephala
(L.) feed identically on leaf discs from control or transformed plants of oilseed rape expressing
constitutively the cysteine proteinase inhibitor, oryzacystatin I (OCI) (Western et al.,
1998). Trypsin inhibitor gene from sweet potato expressed in Taiwan caulifl ower, B. oleracea
var. botrytis, showed resistance to insects (L.C. Ding, Yeh, and Wang, 1998). CpTI gene
and nptII gene were introduced into Brassica campestris L. ssp. chinensis. The insect resistance
of the transgenic plants was maintained in the progeny (She et al., 2000). Modifi ed
CpTi gene (sck) has been successfully transferred into Chinese cabbage, B. campestris subsp.
pekinensis cultivars (GP 11 and Zhongbai 4) (G.D. Yang et al., 2002). The resistance of the
transgenic plants to P. rapae was observed in laboratory and fi eld conditions. A trypsin
inhibitor from Indian mustard, Brassica juncea (L.) Czern. (BjTi, a precursor of a 2S seed
storage protein), showed a soybean trypsin inhibitor active site-like motif (GPFRI ) at the
expected processing site (Mandal et al., 2002). The BjTi is a thermostable Kunitz-type