Selection and Validation of Reference Genes in Different Tissues of Okra ( Abelmoschus esculentus L.) under Different Abiotic Stresses.

Okra ( Abelmoschus esculentus L.) is a particular vegetable with both edible and medicinal values. However, the expression pattern of the okra reference genes in response to abiotic stress has not been explored. In the present study, 18 potential reference genes were selected from okra in various tissues and abiotic stress conditions, and their expression levels were detected by Real-Time quantitative PCR (RT-qPCR). Their expression stabilities were calculated by four algorithms (geNorm, NormFinder, BestKeeper, and RefFinder). Under cold stress, the most stable genes included GAPC1 and CYP (leaf), CYP and ACT7 (root), HIS6 and GAPC1 (stem), and HIS6 and 60s (different tissues). Under salt stress, EF-1α and UBQ (leaf), EF-1α and UBQ (root), TUA4 and Eif (stem), and HIS6 and Eif (different tissues) were the most stable genes. Under drought stress, UBQ and Eif in the leaf, HIS6 and Eif in the root, TUA4 and HIS6 in the stem, and UBQ and Eif in different tissues were most stably expressed in okra. In addition, complete sequencing results by RefFinder showed that HIS6 and ACT7 in the leaf, HIS6 and Eif in the root, UBC5B and 60s in the stem, and HIS6 and Eif in different tissues, were most the suitable reference genes for okra. Furthermore, AeMYB1R1 transcription factor was used to verify the reliability of RT-qPCR values. In summary, this study was carried out to demonstrate the potential reference genes of okra under abiotic stress, aiming to provide a molecular basis for functional gene analysis and regulatory mechanism research of okra.