OsNAC111, a Blast Disease–Responsive Transcription Factor in Rice, Positively Regulates the Expression of Defense-Related Genes

Abstract

Plants respond to pathogen attack by transcriptionally regulating defense-related genes via various types of transcription factors. We identified a transcription factor in rice, OsNAC111, belonging to the TERN subgroup of the NAC family that was transcriptionally upregulated after rice blast fungus (Magnaporthe oryzae) inoculation. OsNAC111 was localized in the nucleus of rice cells and had transcriptional activation activity in yeast and rice cells. Transgenic rice plants overexpressing OsNAC111 showed increased resistance to the rice blast fungus. In OsNAC111-overexpressing plants, the expression of several defense-related genes, including pathogenesis-related (PR) genes, was constitutively high compared with the control. These genes all showed blast disease-responsive expression in leaves. Among them, two chitinase genes and one β-1,3-glucanase gene showed reduced expression in transgenic rice plants in which OsNAC111 function was suppressed by a chimeric repressor (OsNAC111-SRDX). OsNAC111 activated transcription from the promoters of the chitinase and β-1,3-glucanase genes in rice cells. In addition, brown pigmentation at the infection sites, a defense response of rice cells to the blast fungus, was lowered in OsNAC111-SRDX plants at the early infection stage. These results indicate that OsNAC111 positively regulates the expression of a specific set of PR genes in the disease response and contributes to disease resistance.

Transcriptome Analysis Highlights Defense and Signaling Pathways Mediated by Rice pi21 Gene with Partial Resistance to Magnaporthe oryzae

“…The WRKY, AP2/ERF, bHLH, MADS, MYB, and NAC TF families have been reported to be involved in regulating rice defense responses to M. oryzae (Licausi et al, 2013; Yokotani et al, 2014). OsWRKYs are important regulators in rice blast resistance (Wei et al, 2013).…”

“…This result suggests that low expression of WAKY42 may contribute to pi21 partial resistance. NAC122, NAC131, and NAC111 were reported importantly in rice resistance to M. oryzae through regulation of the expression of defense-related genes and/or JA/ET signaling-related genes (Sun et al, 2013; Yokotani et al, 2014). The expression of five NAC TFs was faster and higher in the Pi21 -RNAi line— M. oryzae interaction compared with that in the Nip— M. oryzae interaction during early stages of infection.…”

Transcriptomic Analysis of Responses to Imbalanced Carbon: Nitrogen Availabilities in Rice Seedlings

“…Chitinase, a hydrolytic enzyme belonging to the PR proteins, could hydrolyze the cell wall chitin in most fungi and thus in plants chitinase acts in defense against fungal infection [109]. OsCHT3 , also named as PR3/OsChia1c , functions as a defense-related gene in rice [110]. PR10 are small proteins with a molecular weight of 16 kDa.…”

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

“…Full length and C-terminal Nucleus Promotes lateral root development [139] Associated with seed size in rice [8] (Continued) Full length -Regulates ethylene-mediated chlorophyll degradation during leaf senescence [142] 46 OsNAC111 (Oryza sativa) Full length and C-terminal Nucleus Positively regulates defense responses [143] 47…”