Evaluation of extraction methods for obtaining high-quality RNA from sweet potato
Considering the great economic and social importance of sweet potato and the few transcriptome studies carried out on this species so far, which can potentially lead to significant improvements in its production system at both productivity and quality levels, this study aimed to determine the most suitable methodology for extracting high-quality RNA from sweet potato’s tuberous roots, branches, and leaves. The experiment was composed of three biological replicates, each one comprising three plants. 100 mg of ground tissue was used for isolating RNA through the CTAB and TRIzol methods, while 160 mg was used for the Hot Phenol Acid method. From the three tested protocols, all of them enabled the isolation of RNA at quantities above 250 ng/μL for the three different tissues, which is the minimal quantity required for conducting molecular assays such as RT-qPCR. However, in terms of RNA quality, evaluated through the A260/A280 and A260/A230 ratios, only the Hot Phenol Acid and CTAB methods generated satisfactory results, displaying values from 1.8 to 2.2. To conclude, the hot acid phenol and CTAB methods, not commonly used for transcriptional studies in sweet potato, are excellent choices for the RNA extraction from different sweet potato tissues.