Tobacco rattle virus-induced <i>PHYTOENE DESATURASE</i> ( <i>PDS)</i> and <i>Mg-chelatase H subunit</i> ( <i>ChlH</i> ) gene silencing in <i>Solanum pseudocapsicum</i> L.

Abstract

Virus-induced gene silencing (VIGS) is an attractive tool for determining gene function in plants. The present study constitutes the first application of VIGS in <i>S. pseudocapsicum</i>, which has great ornamental and pharmaceutical value, using <i>tobacco rattle virus</i> (TRV) vectors. Two marker genes, <i>PHYTOENE DESATURASE</i> (<i>PDS</i>) and <i>Mg-chelatase H subunit</i> (<i>ChlH</i>), were used to test the VIGS system in <i>S. pseudocapsicum</i>. The photobleaching and yellow-leaf phenotypes of the silenced plants were shown to significantly correlate with the down-regulation of endogenous <i>SpPDS</i> and <i>SpChlH</i>, respectively (<i>P</i> ≤ 0.05). Moreover, the parameters potentially affecting the efficiency of VIGS in <i>S. pseudocapsicum</i>, including the Agrobacterium strain and the inoculation method (leaf syringe-infiltration, sprout vacuum-infiltration and seed vacuum-infiltration), were compared. The optimized VIGS parameters were the leaf syringe-infiltration method, the Agrobacterium strain GV3101 and the growth of agro-inoculated plants at 25°. With these parameters, the silencing efficiency of <i>SpPDS</i> and <i>SpChlH</i> could reach approximately 50% in <i>S. pseudocapsicum</i>. Additionally, the suitability of various reference genes was screened by RT-qPCR using three candidate genes, and the results demonstrated that glyceraldehyde 3-phosphate dehydrogenase (<i>GAPDH</i>) can serve as a suitable reference for assessing the gene expression levels of VIGS systems in <i>S. pseudocapsicum</i>. The proven application of VIGS in <i>S. pseudocapsicum</i> and the characterization of a suitable reference gene in the present work will expedite the functional characterization of novel genes in <i>S. pseudocapsicum.</i>