The cotton (Gossypium hirsutum) NAC transcription factor (FSN1) as a positive regulator participates in controlling secondary cell wall biosynthesis and modification of fibers

Abstract

Cotton (Gossypium hirsutum) fibers are the highly elongated and thickened single-cell trichomes on the seed epidermis. However, little is known about the molecular base of fiber cell wall thickening in detail. In this study, a cotton NAC transcription factor (GhFSN1) that is specifically expressed in secondary cell wall (SCW) thickening fibers was functionally characterized. The GhFSN1 transgenic cotton plants were generated to study how FSN1 regulates fiber SCW formation. Up-regulation of GhFSN1 expression in cotton resulted in an increase in SCW thickness of fibers but a decrease in fiber length. Transcriptomic analysis revealed that GhFSN1 activates or represses numerous downstream genes. GhFSN1 has the ability to form homodimers, binds to its promoter to activate itself, and might be degraded by the ubiquitin-mediated proteasome pathway. The direct targets of GhFSN1 include the fiber SCW-related GhDUF231L1, GhKNL1, GhMYBL1, GhGUT1 and GhIRX12 genes. GhFSN1 binds directly to a consensus sequence (GhNBS), (C/T)(C/G/T)TN(A/T)(G/T)(A/C/G)(A/G)(A/T/G)(A/T/G)AAG, which exists in the promoters of these SCW-related genes. Our data demonstrate that GhFSN1 acts as a positive regulator in controlling SCW formation of cotton fibers by activating its downstream SCW-related genes. Thus, these findings give us novel insights into comprehensive understanding of GhFSN1 function in fiber development.

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

“…This phenomenon was also observed in other plants, such as in tartary buckwheat and cassava [44,52]. Moreover, several reports have indicated that overexpression of tissue-specifically expressed NAC genes can promote the development of particular tissues, as NAC4 from tomato promoted fruit ripening and carotenoid accumulation [23], cotton NAC transcription factor 1 was involved in secondary cell wall biosynthesis and modification of fibers [19]. Seven highly expressed PmNAC genes (FPKM > 20 in all the tested tissues) originated from subgroup Pm_NAC, suggesting the important roles of the broomcorn millet-specific subgroup Pm_NAC in plant growth and development.…”

“…To further investigate the structural features of broomcorn millet NACs, the conserved motif distributions were analysed. A total of 20 conserved motifs (referred to as motifs [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] were identified by MEME, with more motifs located within the N-terminal region than within the C-terminal region (Fig. 2c).…”

“…NAC TFs play important regulatory roles in various aspects of plant growth, development, and adaptation to the environment, including in shoot apical meristem formation [5], cell division and expansion [6,7] nutrient remobilization [8], flower formation [9], lateral root development [10,11], leaf senescence [12][13][14][15][16], secondary cell wall biosynthesis [3,[17][18][19][20], fiber development [19,21,22], fruit ripening [23,24], seed development [25], response to pathogen infection [26][27][28][29][30], and abiotic stress tolerance [31][32][33]. Many studies have confirmed that many NAC genes play crucial roles in the regulation of plant tolerance to drought.…”

May the Fittest Protein Evolve: Favoring the Plant‐Specific Origin and Expansion of NAC Transcription Factors

“…Full length Nucleus Enhances tolerance to drought and salinity [53] 18 GhFSN1 (Gossypium hirsutum) Full length and C-terminal Nucleus Controls secondary cell wall biosynthesis and modification of fibers [127] 19…”

Analysis of NAC Domain Transcription Factor Genes of Tectona grandis L.f. Involved in Secondary Cell Wall Deposition

“…They are also involved in the signaling pathway induced during biotic and abiotic stresses [18,21,22], and in the regulation of leaf senescence [23]. As for secondary growth, NAC TFs have been described in the regulation of xylogenesis, fiber development, and secondary cell wall formation [24][25][26][27][28][29][30][31][32].…”