Evaluation of Different RNA Extraction Methods from Agropatch Suppressor Assay for Small Quantities of Plant Tissue and Their Application for Analysis of Gene Expression

The agroinfiltration assay provides fast and efficient way to transiently express genes into plant cells by Agrobacterium tumefaciens. Extraction of RNA of high quality and sufficient amounts is prerequisite for gene expression studies such as quantitative Real Time PCR (q-PCR) from infiltrated areas in agropatch suppressor assay with small quantities of plant tissue. To attain prime RNA extraction from small tissues of infiltrated N. benthamiana plants with Potato virus A helper component proteinase viral suppressor protein, the efficiency of three RNA extraction methods (LiCl, TRIzol reagent and commercial kit) was evaluated. The total RNA yield with LiCl method was 2.83 and 33.2-fold greater than that of TRIzol reagent and commercial kit, respectively. Also, total RNA yield using TRIzol reagent was 11.7-fold higher than that with commercial kit. The A260/A280 ratio mean for TRI reagent (1.95) and kit (1.9) extractions were within the optimum range.q-PCR revealed that the cycle threshold values of housekeeping gene, EIF-1α and target genes AGO1 and ATG6 for RNA extracted using LiCl and kit were 1.07 to 1.3 and 1.02 to 1.12 times higher than those evaluated with the TRIzol method. Overall, TRIzol method showed the most effective approach for obtaining RNA from N. benthamiana patches in gene expression studies.