Transgenic tomato plants expressing the Arabidopsis NPR1 gene display enhanced resistance to a spectrum of fungal and bacterial diseases

Abstract

Development of effective disease-resistance to a broad-range of pathogens in crops usually requires tremendous resources and effort when traditional breeding approaches are taken. Genetic engineering of disease-resistance in crops has become popular and valuable in terms of cost and efficacy. Due to long-lasting and broad-spectrum of effectiveness against pathogens, employment of systemic acquired resistance (SAR) for the genetic engineering of crop disease-resistance is of particular interest. In this report, we explored the potential of using SAR-related genes for the genetic engineering of enhanced resistance to multiple diseases in tomato. The Arabidopsis NPR1 (nonexpresser of PR genes) gene was introduced into a tomato cultivar, which possesses heat-tolerance and resistance to tomato mosaic virus (ToMV). The transgenic lines expressing NPR1 were normal as regards overall morphology and horticultural traits for at least four generations. Disease screens against eight important tropical diseases revealed that, in addition to the innate ToMV-resistance, the tested transgenic lines conferred significant level of enhanced resistance to bacterial wilt (BW) and Fusarium wilt (FW), and moderate degree of enhanced resistance to gray leaf spot (GLS) and bacterial spot (BS). Transgenic lines that accumulated higher levels of NPR1 proteins exhibited higher levels and a broader spectrum of enhanced resistance to the diseases, and enhanced disease-resistance was stably inherited. The spectrum and degree of these NPR1-transgenic lines are more significant compared to that of transgenic tomatoes reported to date. These transgenic lines may be further explored as future tomato stocks, aiming at building up resistance to a broader spectrum of diseases.

Tomato RAV Transcription Factor Is a Pivotal Modulator Involved in the AP2/EREBP-Mediated Defense Pathway

“…The resistance of transgenic tomato plants to BW was evaluated as described previously (Lin et al, 2004;Chen et al, 2009). Ralstonia strain Pss4 (race 1, biovar 3; suspension A 600 = 0.6, about 2 3 10 8 cfu mL 21 ) was used as the inoculum.…”

Response of AtNPR1-expressing cotton plants to Fusarium oxysporum f. sp. vasinfectum isolates

“…Similar limitations were observed in the AtNPR1 transformants against Verticillium wilt, where protection was observed only against the non-defoliating isolates of V. dahliae and not the defoliating isolates (Parkhi et al 2010b). Nevertheless, there are a large number of reports that show that NPR1 overexpression confers a strong protection against a variety of diseases (Lin et al 2004;Makandar et al 2006;Malnoy et al 2007;Wally et al 2009;Zhang et al 2010;Dutt et al 2015;Silva et al 2015). Thus, controlled expression of NPR1 gene may still prove to be a useful means to confer tolerance to some pathogens in the field.…”

Increased resistance to fungal wilts in transgenic eggplant expressing alfalfa glucanase gene

“…Genetic engineering of disease resistance by transfer of plant defense-related genes into crops is valuable in terms of cost, efficacy, and reduction of pesticide usage (Lin et al 2004;Wally and Punja 2010;Ceasar and Ignacimuthu 2012). In this study, we explored the possibility of the use of a glucanase gene from alfalfa against two important fungal pathogens of eggplant, viz.…”