|Bell, Alois - Al|
Submitted to: Transgenic Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2010
Publication Date: 2/10/2010
Citation: Parkhi, V., Kumar, V., Campbell, L.M., Bell, A.A., Shah, J., Rathore, K.S. 2010. Resistance against various fungal pathogens and reniform nematode in transgenic cotton plants expressing Arabidopsis NPR1. Transgenic Research. 19:959-975. Interpretive Summary: Cotton suffers 10 percent yield losses annually from a combination of nematodes and soil born fungal pathogens. Increased resistance to the entire disease complex should result in substantial yield increases and increased fiber quality. The NPR1 gene from Arabidopsis thaliana has been shown to increase resistance to various pathogens in several plant species. The investigators incorporated and over expressed this gene in several cotton lines. These lines showed increased resistance to Verticillium wilt, Fusarium wilt, damping-off caused by Rhizoctonia solani and Alternaria leaf spot. The NPR1 gene also suppressed reproduction of reniform nematode and increased plant vigor and yield. Molecular studies showed that the NPR1 lines responded more rapidly and to a greater extent to infection than the wild parent. These lines may be useful in increasing cotton resistance to soil borne disease complexes.
Technical Abstract: Cotton is an economically important crop worldwide that suffers severe losses due to a wide range of fungal/bacterial pathogens and nematodes. Given its susceptibility to various pathogens, it is important to obtain a broad-spectrum resistance in cotton. Resistance to several fungal and bacterial diseases has been obtained by over expressing the Non-expressor of Pathogenesis-Related genes-1 (NPR1) in various plant species with apparently minimal or no pleiotropic effects. We examined the efficacy of this approach in cotton by constitutive expression of the Arabidopsis (Arabidopsis thaliana) NPR1 gene. The results show that NPR 1-expressing lines exhibited significant resistance to Verticillium dahliae isolate TS2, Fusarium oxysporum f. sp. vasinfectum, Rhizoctonia solani, and Alternaria alternata. Interestingly, the transformants also show significant resistance to reniform nematodes. Analysis of defense-related, biochemical and molecular responses suggest that when challenged with pathogens or certain systemic acquired resistance-inducing chemicals, the transgenic lines respond to a greater degree compared to the wild-type plants. Importantly, the basal activities of the defense-related genes and enzymes in uninduced transformants were no different than those in their non-transgenic counterparts. The results provide additional evidence supporting the role of NPR1 as an important part of the plant defense system and suggest a means to achieve broad-spectrum resistance to pathogens via genetic engineering.