Evolutionary Divergence and Biased Expression of NAC Transcription Factors in Hexaploid Bread Wheat (Triticum aestivum L.)

Abstract

The NAC genes, a large plant-specific family of transcription factors, regulate a wide range of pathways involved in development and response to biotic and abiotic stress. In this study, the NAC transcription factors were identified in 27 green plants, and the results showed that NAC transcription factors in plants undergo an appearance stage from water to land and a number expansion stage from gymnosperm to angiosperm. Investigating the evolutionary process of the NAC transcription factors from diploid species to hexaploid wheat revealed that tandem replications during the polyploidization process is an important event for increasing the number of NAC transcription factors in wheat. Then, the molecular characteristics, phylogenetic relationships, and expression patterns of 462 NAC transcription factors of hexaploid wheat (TaNACs) were analyzed. The protein structure results showed that TaNAC was relatively conservative at the N-terminal that contains five subdomains. All these TaNACs were divided into Group I and Group II by phylogenetic analysis, and the TaNACs in Group I should undergo strong artificial selection based on single nucleotide polymorphism (SNP) analysis. Through genome synteny and phylogenetic analysis, these TaNACs were classified into 88 groups and 9 clusters. The biased expression results of these TaNACs showed that there are 24 groups and 67 groups of neofunctionalization genes under biotic and abiotic stress, respectively, and 16 groups and 59 groups of subfunctionalization genes. This shows that neofunctionalization plays an important role in coping with different stresses. Our study provides new insights into the evolution of NAC transcription factors in hexaploid wheat.

Comprehensive analysis of pathogen-responsive wheat NAC transcription factors: new candidates for crop improvement

“…Four studies identified high confidence Triticum aestivum (wheat) NAC s ( TaNAC s) in the cultivar Chinese Spring; Borrill et al (2017) identified 453 TaNAC genes in the TGACv1 genome assembly, while Guérin et al (2019) and Ma et al (2021) identified, respectively, 460 and 462 TaNAC s using a more recent assembly (RefSeq v1.0) and Lv et al (2020) identified 460 TaNAC s in the RefSeq v1.1 genome annotation. Studies from Borrill et al (2017) and Guérin et al (2019) mined RNA-sequencing (RNA-seq) datasets to determine the expression profiles of TaNAC s in different tissues, and in response to biotic and/or abiotic stresses.…”

Overexpression of TaSNAC4-3D in Common Wheat (Triticum aestivum L.) Negatively Regulates Drought Tolerance

“…Many studies performed research on TaNAC identification along with the completion of bread wheat genome sequencing. Totally, 453 TaNACs were identified by Borrill et al (2017) using the wheat genome by TGAC wheat assembly, and Ma J. et al (2021) identified 462 TaNACs using IWGS RefSeq v1.0 database. In this study, we identified 452 TaNACs using the latest version of genome database (IWGSC RefSeq v2.1, Supplementary Table 2 ).…”

Genome-wide identification and expression analysis of the NAC transcription factor family in Saccharum spontaneum under different stresses

“…NAC genes play important roles in plant life activities and responses by plants to biotic and abiotic stresses. 38 Whole-genome analysis of the NAC gene family has been conducted in species that have been sequenced, including O. sativa , 22 Z. mays , 23 ,24 S. bicolor , 25 Triticum aestivum L., 39 Musa acuminata , 40 Vaccinium corymbosum L., 41 Juglans mandshurica , 42 Cleistogenes songorica , and Coffea canephora . 43 , 44 The identification and analysis of S. spontaneum NAC gene families at the whole-genome level have not been reported.…”