THE IMPACT OF SILICON ON TRANSCRIPTS RELATED TO CUCUMBER MOSAIC VIRUS INFECTION IN CUCUMBER.

Abstract

The role of soluble silicon (Si) in alleviating viral plant infections is largely unknown. In order to analyse this gap in knowledge, this study provides insights into the relative gene expression data obtained from 1) control, 2) Cucumber mosaic virus (CMV)-infected and 3) sodium silica-treated, CMV-infected Cucumis sativus line B10 tissue cultures regenerated plants. The absence or presence of CMV was determined through RT-PCR, six days' post-inoculation. qRT-PCR was performed on five selected host genes related to CMV-defence (argonaute protein, WRKY transcription factor) and replication (chaperone, heat shock cognate protein, aquaporin). Relative gene expressions from Si-treated, CMV-infected clones were not significantly different from CMV-infected clones, but they were significantly different from the control plants. The upregulation of the chaperone, and heat shock cognate genes in Si-treated clones, is associated with enhanced virus replication, while the gene expression of the transcription factor increases and is related to defence, in contrast to decreased expression in CMV-infected clones. Aquaporin gene expression was downregulated and the argonaute expression was unaffected in both Si-treated, CMV-infected as well as CMV-infected clones. Since both alleviating and supportive gene shifts are observed in Si-treated plantlets for key genes related to the virus infection examined herein, sodium silica is suggested to have a neutral and limited impact on CMV infection in cucumber cultures.