Genome-wide analysis of the NAC transcription factor family in broomcorn millet (Panicum miliaceum L.) and expression analysis under drought stress

Abstract

Background: Broomcorn millet is a drought-tolerant cereal that is widely cultivated in the semiarid regions of Asia, Europe, and other continents; however, the mechanisms underlying its drought-tolerance are poorly understood. The NAM, ATAF1/2, and CUC2 (NAC) transcription factors form a large plant-specific gene family that is involved in the regulation of tissue development and abiotic stress. To date, NAC transcription factors have not been systematically researched in broomcorn millet.Results: In the present study, a total of 180 NAC (PmNAC) genes were identified from the broomcorn millet genome and named uniformly according to their chromosomal distribution. Phylogenetic analysis demonstrated that the PmNACs clustered into 12 subgroups, including the broomcorn millet-specific subgroup Pm_NAC. Gene structure and protein motif analyses indicated that closely clustered PmNAC genes were relatively conserved within each subgroup, while genome mapping analysis revealed that the PmNAC genes were unevenly distributed on broomcorn millet chromosomes. Transcriptome analysis revealed that the PmNAC genes differed greatly in expression in various tissues and under different drought stress durations. The expression of 10 selected genes under drought stress was analyzed using quantitative real-time PCR. Conclusion: In this study, 180 NAC genes were identified in broomcorn millet, and their phylogenetic relationships, gene structures, protein motifs, chromosomal distribution, duplication, expression patterns in different tissues, and responses to drought stress were studied. These results will be useful for the further study of the functional characteristics of PmNAC genes, particularly with regards to drought resistance.

Genome-wide identification, characterization, and expression analysis of the NAC transcription factor family in orchardgrass (Dactylis glomerata L.)

“…In this study, the tissue-specific expression pattern showed that more than 40 DgNAC genes exhibited higher expression in roots than other detected orchardgrass tissues, such as DgNAC008/052/026/023/034/061/045 . Similar results were also found in other plants, such as Fagopyrum tataricum [ 46 ], Panicum miliaceum [ 47 ] and Triticum aestivum [ 62 ]. DgNAC046, DgNAC087, and DgNAC103 exhibited higher expression than the other genes in the stems of orchardgrass, and they may play an important role in stem development.…”

“…According to the sequence homology with Arabidopsis , all 108 DgNAC genes were divided into 13 subgroups [ 13 ]. The results were inconsistent with other species, such as Fagopyrum tataricum (15 subgroups) [ 46 ], Capsicum annuum (14 subgroups) [ 52 ] and Capsicum annuum (12 subgroups) [ 47 ], suggesting that NAC proteins exhibit diversity in various species. The results of conserved motif analysis of orchardgrass NAC proteins further confirm the classification of the DgNAC family.…”

“…Therefore, orchardgrass has great economic and ecological value, and identification of functional genes is required to improve orchardgrass productivity. NAC genes have been widely studied in various plant species, such as Arabidopsis thaliana [ 13 ], Oryza sativa [ 7 ], Zea mays [ 42 ], Glycine max [ 43 ], Solanum tuberosum [ 44 ], Pyrus bretschneideri [ 45 ], Fagopyrum tataricum [ 46 ], and Panicum miliaceum [ 47 ]. However, the NAC gene family in orchardgrass has not been systematically studied.…”

Transcriptomics of Biostimulation of Plants Under Abiotic Stress

“…Transformed yeast cells expressing OsNAM and OsGRAM showed enhanced tolerance under osmotic stress; moreover, the transformed cells were able to survive at relatively high temperatures, and they displayed increase tolerance to arsenite and arsenate. OsNAM belongs to the NAC family of TFs, which is a large plant-specific gene family that is related to the regulation of tissue development and the response to abiotic stress ( Shan et al, 2020 ). OsGRAM is important for the ABA response, hormone signaling under stress conditions, and the perception of environmental stimuli and regulation of the response to those stimuli ( Mauri et al, 2016 ).…”

UV-B exposure and exogenous hydrogen peroxide application leads to cross-tolerance toward drought in Nicotiana tabacum L

“…NAC13 appears to be an important gene to mediate diverse stress responses in plants. NAC13 expression is induced by UV-B in Arabidopsis independently of the UVR8 photoreceptor (O’Hara et al, 2019) and is also induced by salt stress in poplar (Zhang et al, 2019), and by drought in broomcorn millet (Shan et al, 2020). In our study, however, drought on its own did not induce NAC13 expression in tobacco (Fig.…”