Selection of Suitable Reference Genes for qPCR Normalization under Abiotic Stresses in <i>Oenanthe javanica</i> (BI.) DC

<div><p>Accurate normalization of gene expression data is an absolute prerequisite to obtain reliable results in qPCR analysis. <i>Oenanthe javanica,</i> an aquatic perennial herb, belongs to the <i>Oenanthe</i> genus in <i>Apiaceae</i> family, with known medicinal properties. In the current study, <i>O. javanica</i> was subjected to hormone stimuli (gibberellin, salicylic acid, methyl jasmonate, and abscisic acid) and abiotic stresses (heat, cold, salt, and drought), and the expression of nine candidate reference genes (<i>eIF-4α, ACT7, TIP41, GAPDH, SAND, EF-1α, PP2A, TBP</i>, and <i>TUB</i>) was evaluated. Stability of the genes was assessed using geNorm, NormFinder and BestKeeper. All the genes presented distinct expression profiles under the experimental conditions analyzed. Under abiotic stress conditions, <i>ACT7</i> and <i>PP2A</i> genes displayed the maximum stability; <i>PP2A</i> and <i>SAND</i> were the most stable genes under hormone stimuli. Even though <i>PP2A</i> gene was most stable across all the samples, individual analysis revealed changes in expression profile. To further validate the suitability of the reference genes identified in this study, the expression level of <i>M6PR</i> gene under salt treatment was studied. Based on our data, we propose that it is essential to normalize the target gene expression with specific reference genes under different experimental conditions for most accurate results. To our knowledge, this is the first systematic analysis for reference genes under abiotic stress and hormone stimuli conditions in <i>O. javanica</i>. This will be beneficial for future studies on <i>O. javanica</i> and other plants in <i>Apiaceae</i> family at molecular level.</p>