Production of transgenic rice plants expressing Dioscorea batatas tuber lectin 1 to confer resistance against brown planthopper

Abstract

Dioscorea batatas tuber lectin 1 (DB1) is a storage protein isolated from yam tuber and has been shown to be a mannose-binding lectin. Here we produced transgenic rice plants expressing cDNA of DB1 under the control of phloemspecific promoter of rice sucrose synthase-1 gene. DB1 accumulated at a level of 0.07% of total soluble protein. We then evaluated its efficacy for brown planthopper (BPH). After releasing the first instar of BPH on the transgenic rice plants, the number of survived BPH adults was reduced up to 30% compared to that of wild-type rice. The number of the next generation BPH was suppressed to 22% on average in the seven most-resistant plants compared to that of wild-type rice plants when female adult BPH was inoculated. These results demonstrated that DB1 is effective to confer BPH resistance in terms of decreased survival and fecundity.Key words: Dioscorea batatas tuber lectin 1, insect resistance, planthopper, transgenic rice.Three major sap-sucking pests of rice in Japan: brown planthopper (Nilaparvata lugens, BPH), whitebacked planthopper (Sogatella furcifera, WBPH) and small brown planthopper (Laodelphax striatellus) are known to cause severe damage to rice by sucking or acting as vectors for major viral disease. Recently, these pests have developed resistance to most commercial chemical pesticides (Matsumura et al. 2008). A transgenic approach has been explored to confer rice plants with resistance to such sap-sucking insects. One of the promising genes is encoding mannose-binding protein such as snowdrop lectin (Galanthus nivalis agglutinin; GNA) and garlic leaf lectin (Allium sativum agglutinin from leaf; ASAL). Expression of GNA or ASAL in rice plants has been shown to confer substantial resistance to BPH, WBPH, and green rice planthopper in terms of increased insect mortality, retarded development and decreased fecundity (Rao et al. 1998;Nagadhara et al. 2003Nagadhara et al. , 2004Saha et al. 2006a; Yarashi et al. 2008). Mannose-binding proteins, in general, are known to bind to mannose-containing glycoproteins in the mid-guts of insects, and inhibit growth and development (Sauvion et al. 1996).We have been focusing on Dioscorea batatas tuber lectin 1 (DB1), which has been isolated from yam tuber, Dioscorea batatas Decne., as a storage protein. DB1 is considered to be least non-harmful to human beings, as we Japanese eat raw tubers without boiling them. DB1 is a mannose-binding lectin (23 kDa) consisting of identical 12-kDa subunits. It has 58% and 48% amino-acid identity to GNA and ASAL, respectively, and is classified in the GNA-related lectin family (Gaidamashvili et al. 2004). The insecticidal properties of DB1 have been reported against moth larvae (Helicoverpa armigera). The rate of adults emerging from pupae was reduced to 33%, when fed on 0.01% (w/v) DB1 in an artificial diet (Ohizumi et al. 2009). We also demonstrated that ≥1 mg/ml DB1 in an artificial diet significantly decreased the survival and fecundity of green peach aphid, Myzus persicaeca (Kato et al. 2010). Th...

Genome sequencing of the staple food crop white Guinea yam enables the development of a molecular marker for sex determination

“…The second expansion (red band) consisted of 28 mannose-binding lectins sharing high similarity with Dioscorea batatas tuber lectin DB1 (accession number AB178475). DB1 has insecticidal properties against cotton bollworm ( Helicoverpa armigera ), and studies in transgenic tobacco and rice plants expressing DB1 demonstrated that it also confers resistance against green peach aphid and brown plant hopper, respectively [ 22 – 24 ]. Of these mannose-binding lectin genes in Guinea yam, 16 did not have orthologs in any of the six other species examined, and two showed enriched expression (Benjamini–Hochberg [ 25 ] adjusted P value [padj] < 0.05) in tubers.…”

An underutilized orphan tuber crop—Chinese yam : a review

“…Another major protein stored in Chinese yam tubers is a galactose-binding lectin. This is a defense protein that targets insect pests, suggesting it may be transferrable to other crops (Gaidamashvili et al 2004 ; Ohizumi et al 2009 ; Yoshimura et al 2012 ). This protein has also been shown to inhibit cancer cell growth, and may therefore be useful as a lead to develop new cancer drugs (Yang et al 2011 ; Chan and Ng 2013 ).…”

Development of Transgenic Cotton Lines Expressing Allium sativum Agglutinin (ASAL) for Enhanced Resistance against Major Sap-Sucking Pests

“…It was also reported that transgenic crops expressing garlic lectins (ASA and ASAL) could confer resistance against various lepidopteran and homopteran insects, viz., Nilaparvata lugens , Nephotettix virescens , Sogatella furcifera, Spodoptera littoralis , Lipaphis erysimi and Aphis craccivora [8], [17], [29]-[31]. Further, it was reported that the expression of Dioscorea batatas tuber lectin in rice and tobacco reduced the survival of BPH and aphid by 30% and 60%, respectively [32], [33]. Garlic lectins serve as promising candidate molecules for the development of transgenic crops against sucking pests as they are from edible source, and as such may not pose any biosafety problem.…”