Using a Viral Vector to Reveal the Role of MicroRNA159 in Disease Symptom Induction by a Severe Strain of Cucumber mosaic virus. Issue 3 (3rd February 2014)

• Record Type: Journal Article
• Authors: Du, Zhiyou; Chen, Aizhong; Chen, Wenhu; Westwood, Jack H.; Baulcombe, David C.; Carr, John P.
• Is Part Of: Plant physiology. Volume 164:Issue 3(2014)
• Page Start: 1378
• Page End: 1388
• Publication Date: 2014-02-03
• Subjects: Plant physiology -- Periodicals; Botany -- Periodicals; Periodicals; Electronic journals; 571.2
• DOI: 10.1104/pp.113.232090
• Languages: English
• ISSNs: 0032-0889

Abstract

Abstract : A vector based on a mild strain of Cucumber mosaic virus carrying a microRNA decoy sequence uncovered the relevance of microRNA159 to disease symptoms induced by a severe Cucumber mosaic virus strain . Abstract: In transgenic Arabidopsis ( Arabidopsis thaliana ), expression of the Cucumber mosaic virus (CMV ) 2b silencing suppressor protein from the severe subgroup IA strain Fny disrupted microRNA (miRNA )-regulated development but orthologs from mild subgroup II strains (Q and LS) did not, explaining strain-specific differences in symptom severity. However, it is unknown which miRNA s affected by Fny2b critically affect viral symptoms. Observations that Fny2b -transgenic plants phenocopy microRNA159ab ( mir159ab ) mutant plants and that Fny2b altered miR159ab-regulated transcript levels suggested a role for miR159ab in elicitation of severe symptoms by Fny-CMV. Using restoration of the normal phenotype in transgenic plants expressing an artificial miRNA as a proof of concept, we developed a LS-CMV-based vector to express sequences mimicking miRNA targets. Expressing a miR159 target mimic sequence using LS-CMV depleted miR159 and induced symptoms resembling those of Fny-CMV. Suppression of Fny-CMV-induced symptoms in plants harboring mutant alleles for the miR159ab targets MYB DOMAIN PROTEIN33 ( MYB33 ) and MYB65 confirmed the importance of this miRNA in pathogenesis. This study demonstrates the utility of a viral vector to express miRNA target mimics to facilitate functional studies of miRNA s in plants.