Broad-spectrum disease resistance to necrotrophic and biotrophic pathogens in transgenic carrots (<Emphasis Type="Italic">Daucus carota</Emphasis> L.) expressing an Arabidopsis <Emphasis Type="Italic">NPR1</Emphasis> gene |
| |
Authors: | Owen Wally Jayaraman Jayaraj Zamir K Punja |
| |
Institution: | (1) Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada |
| |
Abstract: | The development of transgenic plants highly resistant to a range of pathogens using traditional signal gene expression strategies
has been largely ineffective. Modification of systemic acquired resistance (SAR) through the overexpression of a controlling
gene such as NPR1 (non-expressor of PR genes) offers an attractive alternative for augmenting the plants innate defense system. The Arabidopsis (At) NPR1 gene was successfully introduced into ‘Nantes Coreless’ carrot under control of a CaMV 35S promoter and two independent transgenic
lines (NPR1-I and NPR1-XI) were identified by Southern and Northern blot hybridization. Both lines were phenotypically normal
compared with non-transformed carrots. Northern analysis did not indicate constitutive or spontaneous induction in carrot
cultures of SAR-related genes (DcPR-1, 2, 4, 5 or DcPAL). The duration and intensity of expression of DcPR-1, 2 and 5 genes were greatly increased compared with controls when
the lines were treated with purified cell wall fragments of Sclerotinia sclerotiorum as well as with 2,6-dichloroisonicotinic acid. The two lines were challenged with the necrotrophic pathogens Botrytis
cinerea, Alternaria radicina and S. sclerotiorum on the foliage and A. radicina on the taproots. Both lines exhibited 35–50% reduction in disease symptoms on the foliage and roots when compared with non-transgenic
controls. Leaves challenged with the biotrophic pathogen Erysiphe heraclei or the bacterial pathogen Xanthomonas hortorum exhibited 90 and 80% reduction in disease development on the transgenic lines, respectively. The overexpression of the SAR
controlling master switch in carrot tissues offers the ability to control a wide range of different pathogens, for which there
is currently little genetic resistance available. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|