Expression of snowdrop lectin (GNA) in transgenic rice plants confers resistance to rice brown planthopper

Abstract

SummarySnowdrop lectin (Galanthus nivalis agglutinin; GNA) has been shown previously to be toxic towards rice brown planthopper (Nilaparvata lugens; BPH) when administered in artificial diet. BPH feeds by phloem abstraction, and causes 'hopper burn', as well as being an important virus vector. To evaluate the potential of the gna gene to confer resistance towards BPH, transgenic rice (Oryza sativa L.) plants were produced, containing the gna gene in constructs where its expression was driven by a phloemspecific promoter (from the rice sucrose synthase RSs1 gene) and by a constitutive promoter (from the maize ubiquitin ubi1 gene). PCR and Southern analyses on DNA from these plants confirmed their transgenic status, and that the transgenes were transmitted to progeny after selffertilization. Western blot analyses revealed expression of GNA at levels of up to 2.0% of total protein in some of the transgenic plants. GNA expression driven by the RSs1 promoter was tissue-specific, as shown by immunohistochemical localization of the protein in the non-lignified vascular tissue of transgenic plants. Insect bioassays and feeding studies showed that GNA expressed in the transgenic rice plants decreased survival and overall fecundity (production of offspring) of the insects, retarded insect development, and had a deterrent effect on BPH feeding. gna is the first transgene to exhibit insecticidal activity towards sap-sucking insects in an important cereal crop plant.

Transgenic indica rice resistant to sap‐sucking insects

“…Marked decreases in the honeydew production of both BPH (80.08%) and GLH (69.06%) insects were observed when fed on T 2 homozygous plants ( Figure 6), thus suggesting the high feeding deterrent effect of GNA against both the insects. Earlier, it was reported that transgenic rice expressing GNA exhibits resistance to BPH when assayed under controlled laboratory conditions (Loc et al, 2002;Maqbool et al, 2001;Rao et al, 1998). The insect bioassays reported in this study were carried out by the standard screening techniques These results represent the first report on transgenic indica rice exhibiting a high degree of resistance against BPH and GLH pests.…”

“…The present study deals with the Agrobacterium-mediated plants is higher than the expression levels which were previously reported using the RSs1 promoter (Rao et al, 1998).…”

“…Earlier investigations (Powell et al, 1993) indicated that the snowdrop-lectin protein (GNA), which was isolated from the ornamental monocotyledonous plant, Galanthus nivalis (snowdrop), belonging to Amarillidaceae family, is toxic to sap-sucking insects of rice. Furthermore, it was reported that the snowdrop-lectin gene (gna), which is expressed in japonica rice (Rao et al, 1998) and wheat (Stoger et al, 1999), conferred resistance against rice brown planthopper and grain aphid, respectively. Recently, it has been shown that the transgenic rice expressing GNA, conferred enhanced resistance to the rice small brown planthopper (Wu et al, 2002).…”

Carbohydrate/glycan-binding specificity of legume lectins in respect to their proposed biological functions

“…Apart of present status of the investigation about the lectins as tools in crop biotechnology, a condition sine qua non for their use is the test to engineered plant for resistance in field. In this way, some non legume plants have already been used (Rao et al, 1998). A set of amino acid to define the monosaccharide specificity In a view of the understanding of the role of legume lectins under the symbiosis establishment or any other activity, the differences in their active combining site and specificity for carbohydrate should be considered.…”

Effectiveness of garlic lectin on red spider mite of tea

“…To date, several plants' lectins have been demonstrated to reduce insect survival, development and fecundity both in vitro and in planta against a wide range of insect orders including Lepidoptera, Coleoptera, Diptera and Homoptera (Peumans & Van Damme 1995;was documented through artificial diet bioassay (Powell et al 1995a,b;Powell 2001) and expression in transgenicplants (Hilder et al 1995;Rao et al 1998;Foissac et al 2000;Loc et al 2002;Nagad-hara et al 2003;Ramesh et al 2004) using mannose binding Galanthus nivalis agglutinin (GNA). Later another mannose-binding 25 kDa homodimeric lectin Allium sativum leaf agglutinin (ASAL) having a high degree of sequence similarity with GNA has been identified by us as a prospective control agent antagonistic to various sucking pests including Myzus persicae, Lipaphis erysimi, green leaf hopper and Aphis craccivora in both artificial diet and transgenic situation (Bandyopadhyay et al 2001;Banerjee et al 2004;Majumder et al 2004Majumder et al , 2005Dutta et al 2005a,b;Saha et al 2006Saha et al , 2007.…”