Transgenic Tomato Plants Expressing Satellite RNA Are Tolerant to Some Strains of Cucumber Mosaic Virus

Abstract

<jats:p>Transgenic tomato plants (<jats:italic>Lycopersicon esculentum</jats:italic> Mill.) expressing cucumber mosaic virus (CMV) satellite RNA fused to a gene for β-glucuronidase were produced using <jats:italic>Agrobacterium</jats:italic>-mediated transformation. The R<jats:sub>1</jats:sub> progeny of self-crossed R<jats:sub>0</jats:sub> plants were challenge-inoculated with virion or RNA preparations of CMV or tomato aspermy virus (TAV). The transgenic plants challenged with CMV-1 showed mild disease symptoms in the first 2 weeks postchallenge followed by a decrease in symptoms, resulting in little difference between the transgenic and uninfected control group by the fourth week. Enzyme-linked immunosorbent assay results showed about a 10-fold decrease in virus accumulation in the transgenic plants compared to controls. Tolerance was evident only in plants that contained the recombinant insert and produced mature unit-length satellite RNA after CMV infection. Plants challenged with TAV showed no significant tolerance to virus-induced symptoms.</jats:p>

Application of plant growth-promoting rhizobacteria (PGPR) in combination with a mild strain ofCucumber mosaic virus(CMV) associated with viral satellite RNAs to enhance growth and protection against a virulent strain of CMV in tomato

“…PGPR-mediated biocontrol can be extended to foliar and systemic diseases, even when the PGPRs are applied to seeds and roots (Kloepper et al, 1999). The reduction in virus titre due to the presence of PGPRs and satellite virus agrees with previous results reported by Murphy et al (2003) and McGarvey et al (1994). We observed that both PGPRs and CMV-KU1 strain associated with the viral satellite RNA require a minimum of 3 weeks to establish themselves and provide protection (data not shown).…”

Structure and Functional Relationships of Satellite RNAs of Cucumber Mosaic Virus

“…The satellite RNA also attenuated CMV-or TAV-indllced symptoms and redllced the accumlllation 01' CMV, but not 01' TA V (HARRISON et a\. 1992;MCGARVEY et al 1994), but nol against TAV-induced disease (MCGARVEY ct al. Similar tolerance to CMV-induced disease and reduction in CMV accumulation was observed when a unit-Iength satellite RNA was expressed transgenically and when CMV was introduced via an aphid vcctor (JACQUEMOND et al 1988).…”

Transgenic Resistance

“…Thus, a direct application of the satRNA technology was developed in transgenic tomato plants as a protection strategy against CMV. When the same plants were challenged with Tomato aspermy virus, another cucumovirus, they showed satRNA replication but neither helper virus downregulation nor significant tolerance to virus-induced symptoms (McGarvey, Montasser, & Kaper, 1994). Quantitative assays showed that replication of transcript satRNA induced a 10-fold decrease in CMV accumulation in the transgenic tomato plants compared to controls.…”