Identification of reference genes for transcript normalization in various tissue types and seedlings subjected to different abiotic stresses of woodland strawberry Fragaria vesca

Abstract Quantitative real-time PCR (qRT-PCR) is one of the most popular methods for gene expression studies. However, data on the usage of reference genes in strawberry are limited. In this study, we assayed expression dynamics of 20 candidate reference genes across various organs (root, leaf and flower), different developmental stages of fruits, and in seedlings under abiotic stresses (heat, cold, drought and salt) in woodland strawberry Fragaria vesca. Expression stability of those genes was analyzed by four commonly used statistical algorithms (geNorm, NormFinder, BestKeeper and dalteCt) for comparisons and rankings. Our results indicate that the expression stability of reference genes varies according to tissue types and experimental conditions. Furthermore, two reference genes are sufficient for normalization in tissues and seedlings under the four stress conditions in Fragaria vesca. We recommend FveSAND and FveMT1, FveCHC1 and FveGAPDH as reference genes in organs and fruits, FveCHC1 and FveTIM1, FveSAND and FveTIM1, FveCHP1 and FveAP1, FveCHC1 and FveEF 1a under heat, cold, drought and salt stress conditions, respectively. Our study provides a set of reliable standard reference genes for expression analyses of genes in various tissue types and seedlings under different environment conditions of Fragaria vesca.