Plant NAC transcription factors in the battle against pathogens

Abstract

Background: The NAC transcription factor family, which is recognized as one of the largest plant-specific transcription factor families, comprises numerous members that are widely distributed among various higher plant species and play crucial regulatory roles in plant immunity.

Results: In this paper, we provided a detailed summary of the roles that NAC transcription factors play in plant immunity via plant hormone pathways and reactive oxygen species pathways. In addition, we conducted in-depth investigations into the interactions between NAC transcription factors and pathogen effectors to summarize the mechanism through which they regulate the expression of defense-related genes and ultimately affect plant disease resistance.

Conclusions: This paper presented a comprehensive overview of the crucial roles that NAC transcription factors play in regulating plant disease resistance through their involvement in diverse signaling pathways, acting as either positive or negative regulators, and thus provided references for further research on NAC transcription factors.

Keywords: Effector; Hormone; NAC transcription factor; Plant immunity; ROS.

Fig. 1

Important regulatory components in plant immunity. (A) Different components regulate resistance in plants. PRRs, pattern recognition receptors; CPKs, calcium-dependent protein kinases; RLCKs, receptor-like cytoplasmic kinases; PBL2, a receptor-like cytoplasmic kinase; PBL2^UMP, uridylylated PBL2; RKS1, resistance-related kinase 1; ZAR1, HopZ-activated resistance 1; TFs, transcription factors; MAPK, mitogen-activated protein kinase; MAPKK, MAPK kinase; MAPKKK, MAPKK kinase; ROS, reactive oxide species. (B) Different pathways of NAC transcription factors are involved in plant disease resistance regulation. HR, hypersensitivity response

Fig. 2

Structural analysis and classification of NAC proteins. (A) Schematic diagram of the typical NAC protein structure. NAC proteins consist of a relatively conserved NAC domain located at the N-terminal region and a variable transcriptional regulatory region located at the C-terminal region. (B) Sequence alignment of NAC domains of some NAC genes involved in resistance to pathogen in A. thaliana and Oryza sativa. The NAC domain is divided into five main subdomains (A ~ E). (C) Pictorial representation for transgene technology of rice for resistance to blast disease. OE, overexpression of NAC gene in rice. (D) Phylogenetic tree of the NAC family TFs in Oryza sativa and A. thaliana. MUSCLE software (version 3.8) [29] was used for multiple sequence alignment, and a rootless evolutionary tree analysis was then performed using TreeBest software. The phylogenetic tree was visualized with the ‘ggtree’ package (version 3.2.1) [30] in R (version 4.1.2)

Fig. 3

NAC transcription factors involved in the regulation of ROS homeostasis response to pathogens. The BnaNACs include BnaNAC55, BnaNAC56, BnaNAC87 and BnaNAC103; DRG1, defense-related genes 1, include OsHSP90 and IREN; DRG2, defense-related genes 2, include ZEN1, ZAT12, HIN1, and PR5; and MG, methylglyoxal. The solid lines represent a direct effect, and the dashed lines represent an indirect effect

Fig. 4

NAC transcription factors targeted by effectors from pathogens during infection. The figure mainly shows the effectors of bacteria, fungi, oomycetes, and viruses. TMV, tobacco mosaic virus; WDV, wheat dwarf geminivirus