Li Huang

BACKGROUND: The NAC (NAM, ATAF1/2, and CUC2) transcription factor family represents a group of large plant-specific transcriptional regulators, participating in plant development and response to external stress. However, there is no comprehensive study on the NAC genes of Tartary buckwheat (Fagopyrum tataricum), a large group of extensively cultivated medicinal and edible plants. The recently published Tartary buckwheat genome permits us to explore all the FtNAC genes on a genome-wide basis. RESULTS: In the present study, 80 NAC (FtNAC) genes of Tartary buckwheat were obtained and named uniformly according to their distribution on chromosomes. Phylogenetic analysis of NAC proteins in both Tartary buckwheat and Arabidopsis showed that the FtNAC proteins are widely distributed in 15 subgroups with one subgroup unclassified. Gene structure analysis found that multitudinous FtNAC genes contained three exons, indicating that the structural diversity in Tartary buckwheat NAC genes is relatively low. Some duplication genes of FtNAC have a conserved structure that was different from others, indicating that these genes may have a variety of functions. By observing gene expression, we found that FtNAC genes showed abundant differences in expression levels in various tissues and at different stages of fruit development. CONCLUSIONS: In this research, 80 NAC genes were identified in Tartary buckwheat, and their phylogenetic relationships, gene structures, duplication, global expression and potential roles in Tartary buckwheat development were studied. Comprehensive analysis will be useful for a follow-up study of functional characteristics of FtNAC genes and for the development of high-quality Tartary buckwheat varieties.

BACKGROUND: AP2/ERF transcription factors perform indispensable functions in various biological processes, such as plant growth, development, biotic and abiotic stresses responses. The AP2/ERF transcription factor family has been identified in many plants, and several AP2/ERF transcription factors from Arabidopsis thaliana (A. thaliana) have been functionally characterized. However, little research has been conducted on the AP2/ERF genes of tartary buckwheat (Fagopyum tataricum), which is an important edible and medicinal crop. The recently published whole genome sequence of tartary buckwheat allowed us to study the tissue and expression profiles of AP2/ERF genes in tartary buckwheat on a genome-wide basis. RESULTS: In this study, 134 AP2/ERF genes of tartary buckwheat (FtAP2/ERF) were identified and renamed according to the chromosomal distribution of the FtAP2/ERF genes. According to the number conserved domains and gene structure, the AP2/ERF genes were divided into three subfamilies by phylogenetic tree analysis, namely, AP2 (15 members), ERF (116 members) and RAV (3 members). A total of 10 motifs were detected in tartary buckwheat AP2/ERF genes, and some of the unique motifs were found to be important for the function of AP2/ERF genes. CONCLUSION: A comprehensive analysis of AP2/ERF gene expression patterns in different tissues and fruit development stages by quantitative real-time PCR (qRT-PCR) showed that they played an important role in the growth and development of tartary buckwheat, and genes that might regulate flower and fruit development were preliminarily identified. This systematic analysis establishes a foundation for further studies of the functional characteristics of FtAP2/ERF genes and improvement of tartary buckwheat crops.