Selective recruitment of NAT10-catalyzed ac4C-modified mRNAs into stress granules by poly(A)-binding protein promotes mRNA stability and plant heat stress tolerance.
The critical role of phase separation in plant heat stress tolerance is revealed and it is demonstrated that N-acetyltransferase 10 (NAT10), which encodes of the cytosine N4 acetyltransferase protein, contributes to heat resistance.
Abstract
Global warming poses a considerable threat to crop production, making heat stress a pivotal challenge in agriculture. Yet how epitranscriptomic modifications contribute to plant heat stress responses remains to be explored. Here, this study reveals the critical role of phase separation in plant heat stress tolerance and demonstrated that N-acetyltransferase 10 (NAT10), which encodes of the cytosine N4 acetyltransferase protein, contributes to heat resistance. We found that NAT10 interacts with polyadenylate-binding protein (PABP), which contains intrinsically disordered regions (IDRs), thereby facilitating the selective recruitment of ac4C-modified mRNAs into PABP-mediated condensates. Integrative transcriptome-wide analysis, combining ac4C acetylome profiling with SG-enriched transcript sequencing, revealed that detoxification-related mRNAs, including those encoding the cytochrome P450, phenylalanine ammonia-lyase, glutathione S-transferase, and heat shock 70 protein families, preferentially accumulate within these condensates. This accumulation maintains their stability and prevents stress-induced degradation. Conversely, loss of PABP impairs the recruitment of ac4C-modified detoxification-related transcripts into stress granules, thereby promoting their degradation under heat stress. In summary, our findings identify a stress-responsive NAT10-PABP-ac4C axis that promotes phase separation to stabilize ac4C-modified mRNAs under heat stress. By recruiting detoxification-related transcripts into stress granules, this axis ensures mRNA stability and offers insights for enhancing crop resilience under environmental stress.
Global warming threatens agricultural productivity, making it crucial to understand how plants perceive and respond to heat stress. Although various metabolic pathways are known to participate in plant heat responses, the role of metabolites in post-translational regulation under heat stress remains poorly understood. Here, we report that methylglyoxal (MG) functions as a negative modulator of plant thermotolerance. We demonstrate that heat stress induces the accumulation of the photorespiratory metabolite 2-phosphoglycolate (2PG), which inhibits the activity of plastid triose phosphate isomerase (pdTPI), leading to increased MG levels. Through a proteomic approach, we identified the chloroplast chaperone cpHSC70-1 as a primary target of MG. MG modifies cpHSC70-1 at a conserved arginine residue (R373), inhibiting its ATPase activity and consequently impairing chloroplast protein import under heat stress. Genetic evidence confirms that the 2PG-pdTPI module controls MG accumulation, and that MG exerts its thermosensitive effect through cpHSC70-1. Our work reveals a photorespiratory metabolite-driven post-translational regulatory pathway, elucidating a novel mechanism for metabolic control of plant thermotolerance.
Fengqin Ding, Yue-Xin Liu, Shi-Hang Fan et al.· Molecular Plant· 0 citations
Heat stress (HS) has emerged as a significant environmental factor affecting plant growth and agricultural productivity. Alternative polyadenylation (APA) is a crucial co-transcriptional process that regulates developmental processes and stress responses in plants. However, the distinct roles of its resultant transcripts in plant HS response remain to be investigated. In this study, we employed poly(A) tag sequencing (PAT-seq) to identify over 1500 transcripts whose expression exhibited significant alterations in response to HS, mediated by SIZ1, a SUMO E3 ligase in Arabidopsis. Further analysis revealed that more than 300 switch genes with varying poly(A) site usages were differentially expressed under HS conditions. Compared to non-canonical poly(A) sites, more genes utilize 3’UTR sites to regulate transcript expression by altering the usage of poly(A) signals. Based on the information of APA genes regulated by SIZ1, we selected two genes, Galactinol synthase enzyme (GolS2) and Tetratricopeptide repeat (TPR) like 3 (TTL3), for characterizing their novel functions. Overexpression of the distal transcript of GolS2 or the proximal transcript of TTL3 enhanced heat tolerance in Arabidopsis. Collectively, our current study elucidates the regulation of APA mediated by SIZ1 during HS response and establishes a strategy for identifying specific transcripts arising from APA for plant heat tolerance.
Jun Wang, Xiujuan Wu, Zhou Zhou et al.· Stress Biology· 0 citations
BACKGROUND
Lysine acetylation of transcription factors (TFs) is essential for plant adaptation to abiotic stress, yet its role in the salt tolerance of woody halophytes remains unclear.
RESULTS
Using 4D label-free quantitative acetylproteomics, we profiled the lysine acetylome of Tamarix hispida under 200 mM NaCl stress. We identified 7,557 lysine acetylation (Kac) sites on 3,136 proteins, of which 559 sites on 478 proteins were salt-responsive. KEGG enrichment analysis revealed that these proteins were primarily involved in pyruvate metabolism and carotenoid biosynthesis, suggesting that acetylation remodels central metabolic pathways during salt adaptation. Salt stress also increased acetylation of five histones and two histone acetyltransferases (KAT3 and NAT3), implicating epigenetic mechanisms. Among 24 acetylated proteins from six families of TFs and one non-TF target protein (HSP), HSPs and zinc-finger types were predominant. Mutation of Kac sites in four selected proteins (ThNAC68, ThCHCC, ThC3H, ThHSP70) abolished their salt-induced acetylation. Transient overexpression of wild-type versions enhanced salt tolerance, lowering malondialdehyde (MDA) and reactive oxygen species (ROS) while elevating proline, chlorophyll, and antioxidant enzyme activities; these effects were lost in acetylation-defective mutants.
CONCLUSIONS
Our work delineates the lysine acetylome of T. hispida under salt stress and establishes TF acetylation as a key regulatory layer in salt adaptation, offering new insights into post-translational and epigenetic networks underlying stress tolerance in woody plants.
Xin Xu, Xianguang Nie, Xuefei Xu et al.· BMC Plant Biology· 0 citations
Abstract Soil salinization is a major abiotic stress limiting wheat production. Although transcriptional responses to salt stress are well-studied, the role of posttranscriptional regulation, particularly through RNA modifications, remains unclear in wheat (Triticum aestivum L.). Here, we present an integrated analysis of the early salt stress response using Nanopore direct RNA sequencing and quantitative proteomics. We generated genome-wide maps of N6-methyladenosine (m6A) modifications, concurrently profiling alternative polyadenylation events and poly(A) tail length dynamics. This multiomics approach characterizes coordinated epitranscriptomic reprogramming and enabled the construction of a regulatory network linking m6A marks to proteomic changes. Furthermore, we identified and functionally validated the putative m6A reader protein EVOLUTIONARILY CONSERVED C-TERMINAL REGION 5 (TaECT5) as a positive regulator of wheat salt tolerance. Our study provides a systems-level view of posttranscriptional regulation during salt stress in wheat and identifies potential targets for enhancing salt tolerance.
J. Zang, Qian Zhang, Yuyu Zhang et al.· Plant Physiology· 0 citations
It is found that heat-induced CHH methylation targets specific genomic loci in a developmental stage-specific manner, with a differentially methylated window located within 6 kb of AT5G44410, an F-box protein-encoding gene.
Introduction Widespread dicamba use poses challenges of resistance and phytotoxicity. To investigate the temporal molecular response mechanisms of tobacco, this study performed a time-resolved transcriptomic analysis of tobacco seedlings exposed to dicamba. Methods Samples were collected at 6, 24, and 72 h after treatment. Results Results indicated that tobacco exhibits a putative three-phase transcriptional adaptation pattern of “perception-defense-repair”. In the early stage (6h), NtIAA genes were rapidly induced alongside activation of the glutathione system, potentially alleviating oxidative stress; at the mid-stage (24h), enhanced carotenoid synthesis and thylakoid reconstruction appeared to protect photosynthetic structures; at the late stage (72h), the transcriptional response shifted toward systemic repair through secondary metabolism, including phenylpropanoid biosynthesis. Predictive regulatory network analysis suggested that the ERF transcription factor Nitab4.5_0000015g0020 may act as a candidate hub, potentially linking auxin signaling and ribosomal protein genes. Discussion Taken together, this study provides transcriptomic evidence that the NtIAA family may serve as candidate genes in response to dicamba, offering potential genetic candidates for breeding herbicide-resistant crops.
Zhaopeng Luo, Lifeng Jin, Peilin Li et al.· Frontiers in Plant Science· 0 citations