Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) is a nutritional crop, which has high rutin, and is good for health. Until now, plant genetic engineering is insufficient for Tartary buckwheat. Abscisic acid (ABA), as one of phytohormones, is involved in the regulation of plant growth and development, and responses to diverse environmental challenges. Although ABA receptors have been well characterized in Arabidopsis, it is little understood in Tartary buckwheat. In this study, we identified 12 ABA receptors, designated as FtRCAR1 through FtRCAR12 in Tartary buckwheat. FtRCARs are divided into three subfamily. Based on the similarity, we could predict that FtRCARs comprise of the monomeric (FtRCAR1, 3, 4, 5, 9, 10, 11 and 12) and the dimeric (FtRCAR2, 7 and 8) state in solution. The analysis of the transcript pattern indicated that most of FtRCARs were significantly variable among the root, stem, leaf, flower and seed, while FtRCAR4 transcript was undetectable under in all tissues. The transcript levels of FtRCARs under ABA treatment indicated that most FtRCARs transcripts were depressed, indicating a possible feedback regulation of ABA signaling. The analysis of rutin biosynthesis related-genes indicated that ABA up-graduated CHS, CHI, F3'H, F3H and FLS transcript levels, while transcripts of 4CL and PAL were down-regulated. In addition, the transcription factors that mediated the rutin biosynthesis related-genes were also regulated by exogenous ABA. Thus, the identification and the characterization of FtRCARs would enable us to further understand the role of ABA signal in Tartary buckwheat.
Keywords: ABA receptors; Abscisic acid (ABA); Rutin biosynthesis; Tartary buckwheat; Transcription factors.
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