|Bell, Alois - Al|
Submitted to: Transgenic Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/5/2012
Publication Date: 4/22/2013
Citation: Kumar, V., Joshi, S.G., Bell, A.A., Rathore, K.S. 2013. Enhanced resistance against Thielaviopsis basicola in transgenic cotton plants expressing Arabidopsis NPR1 gene. Transgenic Research. 22(2):359-368. Interpretive Summary: Arabidopsis thaliana has been used extensively as a model to understand the genetic control of disease resistance in plants. The gene AtNPR1 from this plant acts as a master control switch of several immune responses. In previous studies transformed cotton plants containing the AtNPR1 gene were found to be more resistant to several fungal diseases and nematodes. In this study the gene also was shown to increase resistance to Thielaviopsis root rot, an important seedling disease of cotton. The results provide further support for development of broad-spectrum disease resistance in plants by introducing immunity-regulating genes from other plant species.
Technical Abstract: Black root rot, caused by Thielaviopsis basicola, is an important disease in several crops including cotton. We studied the response of AtNPR1-expressing cotton lines, previously shown to be highly resistant to a diverse set of pathogens, to a challenge from T. basicola. In four different experiments, we found significant degree of tolerance in the transgenic lines to black root rot. Although transformants showed the typical root discoloration symptoms similar to the wild-type control plants following infection, their roots tended to recover faster and resumed normal growth. Better performance of transgenic plants is reflected by the fact that they have significantly higher shoot and root mass, longer shoot length, and greater number of boll-set. Transcriptional analysis of the defense response showed that the roots of AtNPR1-overexpressing transgenic plants exhibited stronger and faster induction of most of these defense-related genes, particularly PR1, thaumatin, glucanase, LOX1, and chitinase. The results obtained in this investigation provide furhter support for a broad-spectrum nature of the resistance conferred by overexpression of AtNPR1 gene in cotton.