Abstract：Abstract In the qRT-PCR analysis, selection of suitable reference genes is a prerequisite for the guarantee of accurate result. As the lack of genome information, the reference gene selection is particularly important for Chinese milk vetch (Astragalus sinicus). In this study, expression of seven commonly used housekeeping genes such as GAPDH, Cons7, ELF1B, Tubulin, Ubiquitin E2, Actin A and Actin 20 were assessed by qPCR in different tissues (roots,stems,leaves, flowers and pods) and different treatment (drought stress, waterlogging stress, salt stress, abscisic acid (ABA) stress) of Astragalus sinicus from NingBo. To determine the expression stability of these genes, qRT-PCR data were determined by three software tools (GeNorm, NormFinder and BestKeeper). The results showed that the highest expression stability candidate reference genes of Chinese milk vetch had many differences in the various experimental conditions. Cons7 could express stably under salt stress and waterlogging stress, and Tubulin, Actin 20, GAPDH were top ranked under different tissues, ABA treatment and drought stress respectively. In different tissues, Tubulin could be the best housekeeping gene. Cons7 was considered as the most appropriate housekeeping gene of Chinese milk vetch among abscisic acid treatment, salt stress and flooding stress, while GAPDH could be chosen as the best housekeeping gene under drought stress. The reference genes selected in this study will be helpful for improving the quality of gene expression studies under various stresses in Chinese milk vetch
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