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Tartary buckwheat is a kind of plant which can be used as medicine as well as edible. Abscisic acid (ABA) signaling plays an important role in the response of plants such as tartary buckwheat to drought and other stress. However, there are not many studies on tartary buckwheat by ABA treatment. In this study, the germination, root length, stoma, and anthocyanin accumulation of tartary buckwheat were all significantly affected by ABA. ABA signaling is important for plants to respond to drought and other stresses, the bZIP gene family is an important member of the ABA signaling pathway. Through the analysis of the origin relationship between tartary buckwheat bZIP family and its related species, 19 bZIP genes in tartary buckwheat were found to be relatively conserved, which laid a foundation for further study of bZIP family. The qRT-PCR results showed that most of the group members were induced by ABA treatment, including 0, 15, 30, 50, 70 µM ABA and 0, 0.5, 2, 4, 8, 16, 24 h ABA treatment. These results suggested that ABA could affect the growth and development of tartary buckwheat, and FtbZIPs might have different functions in the response of tartary buckwheat to drought. This study will be helpful to further analyze the genetic breeding and economic value of tartary buckwheat resistance.

Tartary buckwheat ( Fagopyrum tataricum ) is rich in flavonols, which are thought to be highly beneficial for human health. However, little is known about the regulatory mechanism of flavonol biosynthesis in Tartary buckwheat. In this study, we identified and characterized a novel SG7 R2R3-MYB transcription factor in Tartary buckwheat, FtMYB6. We showed that FtMYB6 is located in the nucleus and acts as a transcriptional activator. The FtMYB6 promoter showed strong spatiotemporal specificity and was induced by light. The expression of FtMYB6 showed a significant correlation with rutin accumulation in the roots, stems, leaves, and flowers. Overexpression of FtMYB6 in transgenic Tartary buckwheat hairy roots and tobacco ( Nicotiana tabacum ) plants significantly increased the accumulation of flavonols. In transient luciferase (LUC) activity assay, FtMYB6 promoted the activity of FtF3H and FtFLS1 promoters and inhibited the activity of the Ft4CL promoter. Collectively, our results suggest that FtMYB6 promotes flavonol biosynthesis by activating FtF3H and FtFLS1 expression.

Plants are subjected to a variety of abiotic stresses during their lifetime, and drought and salt stress are some of the main causes of reduced crop yields. Previous studies have shown that AREB/ABFs within bZIP transcription factors are involved in plant drought and salt stress responses in an ABA-dependent manner. However, the properties and functions of AREB/ABFs in Fagopyrum tataricum, a cereal with good resistance to abiotic stresses, are poorly understood. In this study, a gene encoding an AREB/ABF, designated FtbZIP83, was first isolated from Tartary buckwheat. Expression analysis in Tartary buckwheat indicated that FtbZIP83 was significantly induced by abscisic acid (ABA), NaCl and polyethylene glycol (PEG). The overexpression of FtbZIP83 in Arabidopsis resulted in increased drought/salt tolerance, which was attributed not only to higher proline (Pro) contents and antioxidant enzyme activity in transgenic lines compared with controls but also to the lower reactive oxygen species (ROS) accumulation and malondialdehyde (MDA) content. In addition, we found that FtbZIP83 was able to respond to drought and salt stress by upregulating the transcript abundance of downstream ABA-inducible gene. Furthermore, promoter sequence analysis showed that ABREs were present, and the activity of the FtbZIP83 promoter in transgenic Arabidopsis after drought stress was significantly higher than that under normal conditions. Based on the potential signalling pathways involved in AREB/ABFs, we also screened for the interaction protein FtSnRK2.6/2.3, which may phosphorylate FtbZIP83. Collectively, these results provide evidence that FtbZIP83, as a positive regulator, responds to drought/salt stress via an ABA-dependent signalling pathway composed of SnRK2-AREB/ABF., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

The WRKY transcription factor family includes plant-specific transcription factors that are widely involved in plant biotic and abiotic stress responses, growth and development. Tartary buckwheat is a type of small grain with strong resistance to adverse growing conditions. No systematic exploration of the WRKY family in Tartary buckwheat has yet been reported. In this paper, we report the FtWRKY46 gene from Tartary buckwheat and study its role in salt tolerance. FtWRKY46 has transcriptional activation activity in yeast, and FtWRKY46 fused to yellow fluorescent protein localizes to the nucleus. Further studies have found that its transcriptional activation region is located at the N-terminus. A yeast one-hybrid assay indicated that FtWRKY46 could bind to a W-box and activate reporter gene expression. Similarly, transient cotransfection showed that FtWRKY46 could specifically bind to W-box regions and activate reporter gene expression in plants. Furthermore, ectopic expression of FtWRKY46 could enhance Arabidopsis tolerance to salt stress. More specifically, the seed germination rate, root length, chlorophyll content and proline content were significantly higher in transgenic plants ectopically expressing FtWRKY46 than in WT plants after salt stress (P < 0.05), while MDA levels were significantly lower than in WT plants (P < 0.05). Additionally, salt treatment increased the expression of stress-related genes. To summarize, our results suggest that ectopic expression of FtWRKY46 enhance the stress tolerance of transgenic plants by modulating ROS clearance and stress-related gene expression. • FtWRKY46 may activate the expression of target genes by binding to W-box elements in the nucleus. • The ectopic expression of FtWRKY46 resulted in increased salt tolerance in transgenic Arabidopsis. • FtWRKY46 plays a negative regulatory role in the ABA signaling pathway and participates in plant responses to salt stress. [ABSTRACT FROM AUTHOR]

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. • The identification of abscisic acid receptors (FtRCARs) in Tartary Buckwheat. • The characteristics of FtRCARs are shown in the paper. • The genes in rutin biosynthesis signaling pathway were predicted to be mediated by exogenous ABA. • The transcription factors that regulate the rutin biosynthesis in Tartary Buckwheat could also be regulated by ABA. [ABSTRACT FROM AUTHOR]