A membrane‐associated NAC transcription factor OsNTL3 is involved in thermotolerance in rice

Abstract

Summary Heat stress induces misfolded protein accumulation in endoplasmic reticulum (ER), which initiates the unfolded protein response (UPR) in plants. Previous work has demonstrated the important role of a rice ER membrane‐associated transcription factor OsbZIP74 (also known as OsbZIP50) in UPR. However, how OsbZIP74 and other membrane‐associated transcription factors are involved in heat stress tolerance in rice is not reported. In the current study, we discovered that OsNTL3 is required for heat stress tolerance in rice. OsNTL3 is constitutively expressed and up‐regulated by heat and ER stresses. OsNTL3 encodes a NAC transcription factor with a predicted C‐terminal transmembrane domain. GFP‐OsNTL3 relocates from plasma membrane to nucleus in response to heat stress and ER stress inducers. Loss‐of‐function mutation of OsNTL3 confers heat sensitivity while inducible expression of the truncated form of OsNTL3 without the transmembrane domain increases heat tolerance in rice seedlings. RNA‐Seq analysis revealed that OsNTL3 regulates the expression of genes involved in ER protein folding and other processes. Interestingly, OsNTL3 directly binds to OsbZIP74 promoter and regulates its expression in response to heat stress. In turn, up‐regulation of OsNTL3 by heat stress is dependent on OsbZIP74. Thus, our work reveals the important role of OsNTL3 in thermotolerance, and a regulatory circuit mediated by OsbZIP74 and OsNTL3 in communications among ER, plasma membrane and nucleus under heat stress conditions.

Transcriptome profiling and gene expression analyses of eggplant (Solanum melongena L.) under heat stress

“…Four genes (BGI_novel_G004375, BGI_novel_G005221, BGI_novel_G006042, and Sme2.5_00287.1_g00001.1) encoding basic region/leucine zipper proteins were significantly up-regulated in both groups ( Fig 5A ). As previously reported, overexpression of a stress-responsive NAC gene SNAC3 and NTL3 increased heat tolerance in rice [ 45 , 46 ]. OsNTL3 regulated heat stress response by binding to OsbZIP74 promoter.…”

“…OsNTL3 regulated heat stress response by binding to OsbZIP74 promoter. Interestingly, the induction of OsNTL3 expression was depended on OsbZIP74 [ 46 ]. Thus, the NAC genes and bZIP genes in our research may exist the interaction and the detail needs to be further investigated.…”

Plant Responses to Heat Stress: Physiology, Transcription, Noncoding RNAs, and Epigenetics

“…NACs are one of the largest transcription factor families in plants and are involved in the response to HS. NAC transcription factors bind to the promoters of HSFs (e.g., HSFA1b , HSFA6b , HSFA7a , and HSFC1 ), increasing their expression and thus enhancing thermotolerance [ 34 , 35 ]. Moreover, TaNAC2L enhanced heat resistance by regulating the expression of HS-response genes (e.g., AtHSFA3 , AtDREB2A ) in wheat [ 36 ] ( Figure 2 ).…”

NAC Transcription Factors as Positive or Negative Regulators during Ongoing Battle between Pathogens and Our Food Crops

“…Since the discovery of NAC TFs over 20 years ago, the functional study of NAC TFs has attracted extensive attention. In recent years, great progress has been made in understanding how NAC TFs influence plant development and the responses to abiotic and biotic stresses in Arabidopsis and crops [ 13 , 156 , 157 , 158 ]. However, only a few studies on NAC TFs during the response to pathogens in main food crops have been reported, and there are still many unknowns to solve: What are the downstream targets and interaction partners of NAC TFs during pathogen infection?…”