HSP70-4 and farnesylated AtJ3 constitute a specific HSP70/HSP40-based chaperone machinery essential for prolonged heat stress tolerance in Arabidopsis

Plasticity of the Arabidopsis leaf lipidome and proteome in response to pathogen infection and heat stress

Plants must cope with a variety of stressors during their life cycle, and the adaptive responses to these environmental cues involve all cellular organelles. Among them, comparatively little is known about the contribution of cytosolic lipid droplets (LDs) and their core set of neutral lipids and associated surface proteins to the rewiring of cellular processes in response to stress. Here, we analyzed the changes that occur in the lipidome and proteome of Arabidopsis (Arabidopsis thaliana) leaves after pathogen infection with Botrytis cinerea or Pseudomonas syringae, or after heat stress. Analyses were carried out in wild-type plants and the oil-rich double mutant trigalactosyldiacylglycerol1-1 sugar dependent 1-4 (tgd1-1 sdp1-4) that allowed for an allied study of the LD proteome in stressed leaves. Using liquid chromatography-tandem mass spectrometry-based methods, we showed that a hyperaccumulation of the primary LD core lipid TAG is a general response to stress and that acyl chain and sterol composition are remodeled during cellular adaptation. Likewise, comparative analysis of the LD protein composition in stress-treated leaves highlighted the plasticity of the LD proteome as part of the general stress response. We further identified at least two additional LD-associated proteins, whose localization to LDs in leaves was confirmed by confocal microscopy of fluorescent protein fusions. Taken together, these results highlight LDs as dynamic contributors to the cellular adaptation processes that underlie how plants respond to environmental stress.

The Genetics and Breeding of Heat Stress Tolerance in Wheat: Advances and Prospects

Heat stress is one of the major concerns for wheat production worldwide. Morphological parameters such as germination, leaf area, shoot, and root growth are affected by heat stress, with affected physiological parameters including photosynthesis, respiration, and water relation. Heat stress also leads to the generation of reactive oxygen species that disrupt the membrane systems of thylakoids, chloroplasts, and the plasma membrane. The deactivation of the photosystems, reduction in photosynthesis, and inactivation of Rubisco affect the production of photo-assimilates and their allocation, consequently resulting in reduced grain yield and quality. The development of thermo-tolerant wheat varieties is the most efficient and fundamental approach for coping with global warming. This review provides a comprehensive overview of various aspects related to heat stress tolerance in wheat, including damages caused by heat stress, mechanisms of heat stress tolerance, genes or QTLs regulating heat stress tolerance, and the methodologies of breeding wheat cultivars with high heat stress tolerance. Such insights are essential for developing thermo-tolerant wheat cultivars with high yield potential in response to an increasingly warmer environment.

Exogenous MgH2-derived hydrogen alleviates cadmium toxicity through m6A RNA methylation in rice

Cadmium (Cd) contamination poses a substantial threat to crop yields and human health. While magnesium hydride (MgH2) has been reported as a hydrogen (H2) donor that promotes plant growth under heavy metal contamination, its role in rice remains elusive. Herein, seedlings of Oryza sativa L. Japonica variety Zhonghua 11 (ZH11) were selected and exposed to 20 µL of 1-mol/L cadmium chloride (CdCl2) solution via hydroponics to simulate Cd stress. Meanwhile, 0.1 mg of MgH2 was used to slow-release H2 to the experimental group to explore its potential effects on rice over a 2-week period. The results indicated that Cd exposure severely inhibited the growth and development of ZH11 rice seedlings. However, the exogenous slow-release of H2 from MgH2 effectively mitigated this inhibitory effect by restoring the balance of reactive oxygen species (ROS), maintaining endogenous H2 homeostasis, and supporting the photosynthetic system. High-performance liquid chromatography analysis revealed that exogenous H2 reduces m6A RNA methylation levels in mRNA under Cd stress. Consequently, MeRIP-seq was conducted to investigate the effect of Cd exposure in rice in the presence and absence of H2. The m6A modifications were enriched at the start codon, stop codon, and 3' UTR. By integrating RNA-seq data, 118 transcripts were identified as differentially methylated and expressed genes under Cd stress. These gene annotations were associated with ROS, biological stress, and hormonal responses. Notably, 297 differentially methylated and expressed genes were identified under Cd stress in the presence of H2, linked to heavy metals, protein kinases, and calcium signaling regulation. Cd strongly activates the MAPK pathway in response to stress. Exogenous H2 reduces Cd accumulation as well as enhances plant tolerance and homeostasis by lowering m6A levels, thereby decreasing the mRNA stability of these genes. Our findings indicate that MgH2, by supplying H2, regulates gene expression through m6A RNA methylation and confers Cd tolerance in rice. This study provides potential candidate genes for studying the remediation of heavy metal pollution in plants.

Insights into the Heat Shock Protein 70 (Hsp70) Family in Camelina sativa and Its Roles in Response to Salt Stress

Hsp70s, a group of heat shock proteins, are ancient proteins that play a crucial part in maintaining the stability of cells when faced with various internal and external stresses. In this research, there are 72 CsHSP70 genes present and verified in Camelina sativa, all of which exhibit a wide range of physicochemical characteristics. Through evolutionary analysis, the Hsp70 family was categorized into five primary groups, and numerous segmental duplications were anticipated among the CsHSP70 genes. The GO enrichment analysis of co-expression network elements revealed a significant association between key signaling terms, such as phosphorelay signal transduction, and MAPK cascade with the function of CsHsp70. An analysis of transcriptome data exposed to cold, drought, salinity, and cadmium stress demonstrated the varied expression profiles of CsHsp70 genes. The expression levels of CsHSP70 genes varied across various organs and stages of development in camelina, although some of them illustrated tissue-specific expression. qRT-PCR analysis further disclosed that CsHsp70-60, -52, and -13 were up-regulated and CsHsp70-03, -58, and -09 showed down-regulation in response to salinity. Furthermore, CsHsp70 genes are categorized as late-responsive elements to salinity stress. Through docking analysis, the current research revealed that CsHsp70 proteins interacted with ABA, BR, and MeJA.

ERFVII-controlled hypoxia responses are in part facilitated by MEDIATOR SUBUNIT 25 in Arabidopsis thaliana

Flooding impairs plant growth through oxygen deprivation, which activates plant survival and acclimation responses. Transcriptional responses to low oxygen are generally associated with the activation of group VII ETHYLENE-RESPONSE FACTOR (ERFVII) transcription factors. However, the exact mechanisms and molecular components by which ERFVII factors initiate gene expression are not fully elucidated. Here, we show that the ERFVII factors RELATED TO APETALA 2.2 (RAP2.2) and RAP2.12 cooperate with the Mediator complex subunit AtMED25 to coordinate gene expression under hypoxia in Arabidopsis thaliana. Respective med25 knock-out mutants display reduced low-oxygen stress tolerance. AtMED25 physically associates with a distinct set of hypoxia core genes and its loss partially impairs transcription under hypoxia due to decreased RNA polymerase II recruitment. Association of AtMED25 with target genes requires the presence of ERFVII transcription factors. Next to ERFVII protein stabilisation, also the composition of the Mediator complex including AtMED25 is potentially affected by hypoxia stress as shown by protein-complex pulldown assays. The dynamic response of the Mediator complex to hypoxia is furthermore supported by the fact that two subunits, AtMED8 and AtMED16, are not involved in the establishment of hypoxia tolerance, whilst both act in coordination with AtMED25 under other environmental conditions. We furthermore show that AtMED25 function under hypoxia is independent of ethylene signalling. Finally, functional conservation at the molecular level was found for the MED25-ERFVII module between A. thaliana and the monocot species Oryza sativa, pointing to a potentially universal role of MED25 in coordinating ERFVII-dependent transcript responses to hypoxia in plants.

Transcriptomics and metabolomics analyses of Rosa hybrida to identify heat stress response genes and metabolite pathways

BACKGROUND

Global warming has greatly increased the impact of high temperatures on crops, resulting in reduced yields and increased mortality. This phenomenon is of significant importance to the rose flower industry because high-temperature stress leads to bud dormancy or even death, reducing ornamental value and incurring economic losses. Understanding the molecular mechanisms underlying the response and resistance of roses to high-temperature stress can serve as an important reference for cultivating high-temperature-stress-resistant roses.

RESULTS

To evaluate the impact of high temperatures on rose plants, we measured physiological indices in rose leaves following heat stress. Protein and chlorophyll contents were significantly decreased, whereas proline and malondialdehyde (MDA) contents, and peroxidase (POD) activity were increased. Subsequently, transcriptomics and metabolomics analyses identified 4,652 common differentially expressed genes (DEGs) and 57 common differentially abundant metabolites (DAMs) in rose plants from four groups. Enrichment analysis showed that DEGs and DAMs were primarily involved in the mitogen-activated protein kinases (MAPK) signaling pathway, plant hormone signal transduction, alpha-linolenic acid metabolism, phenylpropanoid biosynthesis, and flavonoid biosynthesis. The combined analysis of the DEGs and DAMs revealed that flavonoid biosynthesis pathway-related genes, such as chalcone isomerase (CHI), shikimate O-hydroxycinnamoyl transferase (HCT), flavonol synthase (FLS), and bifunctional dihydroflavonol 4-reductase/flavanone 4-reductase (DFR), were downregulated after heat stress. Moreover, in the MAPK signaling pathway, the expression of genes related to jasmonic acid exhibited a decrease, but ethylene receptor (ETR/ERS), P-type Cu + transporter (RAN1), ethylene-insensitive protein 2/3 (EIN2), ethylene-responsive transcription factor 1 (ERF1), and basic endochitinase B (ChiB), which are associated with the ethylene pathway, were mostly upregulated. Furthermore, heterologous overexpression of the heat stress-responsive gene RcHSP70 increased resistance to heat stress in Arabidopsis thaliana.

CONCLUSION

The results of this study indicated that the flavonoid biosynthesis pathway, MAPK signaling pathway, and plant hormones may be involved in high-temperature resistance in roses. Constitutive expression of RcHSP70 may contribute to increasing high-temperature tolerance. This study provides new insights into the genes and metabolites induced in roses in response to high temperature, and the results provide a reference for analyzing the molecular mechanisms underlying resistance to heat stress in roses.

OsRHS Negatively Regulates Rice Heat Tolerance at the Flowering Stage by Interacting With the HSP Protein cHSP70-4

Heat stress at the flowering stage significantly impacts rice grain yield, yet the number of identified genes associated with rice heat tolerance at this crucial stage remains limited. This study focuses on elucidating the function of the heat-induced gene reduced heat stress tolerance 1 (OsRHS). Overexpression of OsRHS leads to reduced heat tolerance, while RNAi silencing or knockout of OsRHS enhances heat tolerance without compromising yield, as assessed by the seed setting rate. OsRHS is localized in the cytoplasm and mainly expressed in the glume and anther of spikelet. Moreover, OsRHS was found to interact with the HSP protein cHSP70-4, and the knockout of cHSP70-4 resulted in increased heat tolerance. Complementation assays revealed that the knockout of cHSP70-4 could restore the compromised heat tolerance in OsRHS overexpression plants. Additional investigation reveals that elevated temperatures can amplify the bond between OsRHS and cHSP70-4 within rice. Furthermore, our findings indicate that under heat stress conditions during the flowering stage, OsRHS plays a negative regulatory role in the expression of many stress-related genes. These findings unveil the crucial involvement of OsRHS and cHSP70-4 in modulating heat tolerance in rice and identify novel target genes for enhancing heat resilience during the flowering phase in rice.

Heat-shock transcription factor HsfA8a regulates heat stress response in Sorbus pohuashanensis

MAIN CONCLUSION

The SpHsfA8a upregulated expression can induce the expression of multiple heat-tolerance genes, and increase the tolerance of Arabidopsis thaliana to high-temperature stress. Sorbus pohuashanensis is an ornamental tree used in courtyards. However, given its poor thermotolerance, the leaves experience sunburn owing to high temperatures in summer, severely affecting its ornamental value. Heat-shock transcription factors play a critical regulatory role in the plant response to heat stress. To explore the heat-tolerance-related genes of S. pohuashanensis to increase the tree's high-temperature tolerance, the SpHsfA8a gene was cloned from S. pohuashanensis, and its structure and expression patterns in different tissues and under abiotic stress were analyzed, as well as its function in heat tolerance, was determined via overexpression in Arabidopsis thaliana. The results showed that SpHsfA8a encodes 416 amino acids with a predicted molecular weight of 47.18 kDa and an isoelectric point of 4.63. SpHsfA8a is a hydrophilic protein without a signal peptide and multiple phosphorylation sites. It also contains a typical DNA-binding domain and is similar to MdHsfA8a in Malus domestica and PbHsfA8 in Pyrus bretschneideri. In S. pohuashanensis, SpHsfA8a is highly expressed in the roots and fruits and is strongly induced under high-temperature stress in leaves. The heterologous expression of SpHsfA8a in A. thaliana resulted in a considerably stronger growth status than that of the wild type after 6 h of treatment at 45 °C. Its proline content, catalase and peroxidase activities also significantly increased, indicating that the SpHsfA8a gene increased the tolerance of A. thaliana to high-temperature stress. SpHsfA8a could induce the expression of multiple heat-tolerance genes in A. thaliana, indicating that SpHsfA8a could strengthen the tolerance of A. thaliana to high-temperature stress through a complex regulatory network. The results of this study lay the foundation for further elucidation of the regulatory mechanism of SpHsfA8a in response of S. pohuashanensis to high-temperature stress.

Comparative proteomics in tall fescue to reveal underlying mechanisms for improving Photosystem II thermotolerance during heat stress memory

BACKGROUND

The escalating impacts of global warming intensify the detrimental effects of heat stress on crop growth and yield. Among the earliest and most vulnerable sites of damage is Photosystem II (PSII). Plants exposed to recurring high temperatures develop heat stress memory, a phenomenon that enables them to retain information from previous stress events to better cope with subsequent one. Understanding the components and regulatory networks associated with heat stress memory is crucial for the development of heat-resistant crops.

RESULTS

Physiological assays revealed that heat priming (HP) enabled tall fescue to possess higher Photosystem II photochemical activity when subjected to trigger stress. To investigate the underlying mechanisms of heat stress memory, we performed comparative proteomic analyses on tall fescue leaves at S0 (control), R4 (primed), and S5 (triggering), using an integrated approach of Tandem Mass Tag (TMT) labeling and Liquid Chromatography-Mass Spectrometry. A total of 3,851 proteins were detected, with quantitative information available for 3,835 proteins. Among these, we identified 1,423 differentially abundant proteins (DAPs), including 526 proteins that were classified as Heat Stress Memory Proteins (HSMPs). GO and KEGG enrichment analyses revealed that the HSMPs were primarily associated with the "autophagy" in R4 and with "PSII repair", "HSP binding", and "peptidase activity" in S5. Notably, we identified 7 chloroplast-localized HSMPs (HSP21, DJC77, EGY3, LHCA4, LQY1, PSBR and DEGP8, R4/S0 > 1.2, S5/S0 > 1.2), which were considered to be effectors linked to PSII heat stress memory, predominantly in cluster 4. Protein-protein interaction (PPI) analysis indicated that the ubiquitin-proteasome system, with key nodes at UPL3, RAD23b, and UCH3, might play a role in the selective retention of memory effectors in the R4 stage. Furthermore, we conducted RT-qPCR validation on 12 genes, and the results showed that in comparison to the S5 stage, the R4 stage exhibited reduced consistency between transcript and protein levels, providing additional evidence for post-transcriptional regulation in R4.

CONCLUSIONS

These findings provide valuable insights into the establishment of heat stress memory under recurring high-temperature episodes and offer a conceptual framework for breeding thermotolerant crops with improved PSII functionality.

Unveiling HSP40/60/70/90/100 gene families and abiotic stress response in Jerusalem artichoke

Heat shock proteins (HSPs) are essential for plant growth, development, and stress adaptation. However, their roles in Jerusalem artichoke are largely unexplored. Using bioinformatics, we classified 143 HSP genes into distinct families: HSP40 (82 genes), HSP60 (22 genes), HSP70 (29 genes), HSP90 (6 genes), and HSP100 (4 genes). Our analysis covered their traits, evolution, and structures. Using RNA-seq data, we uncovered unique expression patterns of these HSP genes across growth stages and tissues. Notably, HSP40, HSP60, HSP70, HSP90, and HSP100 families each had specific roles. We also studied how these gene families responded to various stresses, from extreme temperatures to drought and salinity, revealing intricate expression dynamics. Remarkably, HSP40 showed remarkable flexibility, while HSP60, HSP70, HSP90, and HSP100 responded specifically to stress types. Moreover, our analysis unveiled significant correlations between gene pairs under stress, implying cooperative interactions. qRT-PCR validation underscored the significance of particular genes such as HtHSP60-7, HtHSP90-5, HtHSP100-2, and HtHSP100-3 in responding to stress. In summary, our study advances the understanding of how HSP gene families collectively manage stresses in Jerusalem artichoke. This provides insights into specific gene functions and broader plant stress responses.

Proteome Analysis of the ROF-FKBP Mutants Reveals Functional Relations among Heat Stress Responses, Plant Development, and Protein Quality Control during Heat Acclimation in Arabidopsis thaliana

In the present study, a differential screening following heat stress acclimation was performed in Arabidopsis thaliana WT and ROF-FKBP mutated plants using mass spectrometry, and the results were used to understand and analyze the effect of the ROF PPIases during thermotolerance acquisition in plants. Our data highlight the central role of these two PPIases in heat stress and point to their direct or indirect effect on other proteins participating in cellular functions such as protein folding and quality control, cell division, photosynthesis, and other metabolic and signaling processes. Specifically, the heat stress response, protein folding, and protein ER processing pathways are enhanced following a 37 °C acclimation period independent of the mutation state. However, at 37 °C, and in the double-mutated rof1-/2- plants, a higher accumulation of proteins belonging to the above pathways is observed compared with all other conditions (WT, single mutants, control, and heat-acclimated plants). Furthermore, the proteasomal pathway, involving the common member of both the protasomal and the lysosomal degradation pathway, CDC48, is over-represented in the extracts of both the untreated and heat-stressed rof1-/2- mutants compared with the other extracts. In contrast, in the single rof1- mutation, the heat acclimation pathway is suppressed at 37 °C when compared to the WT. Protein accumulation related to the heat stress and the protein quality control pathways points to a differential but also synergistic role of the two proteins. Protein complexes of other biochemical and developmental mechanisms, such as the light-harvesting complex of the photosynthetic pathway and the phosphoinositide binding proteins involved in membrane-trafficking events during cell plate formation and cytokinesis (patellin 1, 2, and 4), are negatively regulated in the rof1-/2- mutant. Our results suggest that ROF1 and ROF2 FKBPs regulate stress response, and developmental and metabolic pathways via a complex feedback mechanism involving partners that ensure protein quality control and plant survival during heat stress.

Heat and Wheat: Adaptation strategies with respect to heat shock proteins and antioxidant potential; an era of climate change

Extreme changes in weather including heat-wave and high-temperature fluctuations are predicted to increase in intensity and duration due to climate change. Wheat being a major staple crop is under severe threat of heat stress especially during the grain-filling stage. Widespread food insecurity underscores the critical need to comprehend crop responses to forthcoming climatic shifts, pivotal for devising adaptive strategies ensuring sustainable crop productivity. This review addresses insights concerning antioxidant, physiological, molecular impacts, tolerance mechanisms, and nanotechnology-based strategies and how wheat copes with heat stress at the reproductive stage. In this study stress resilience strategies were documented for sustainable grain production under heat stress at reproductive stage. Additionally, the mechanisms of heat resilience including gene expression, nanomaterials that trigger transcription factors, (HSPs) during stress, and physiological and antioxidant traits were explored. The most reliable method to improve plant resilience to heat stress must include nano-biotechnology-based strategies, such as the adoption of nano-fertilizers in climate-smart practices and the use of advanced molecular approaches. Notably, the novel resistance genes through advanced molecular approach and nanomaterials exhibit promise for incorporation into wheat cultivars, conferring resilience against imminent adverse environmental conditions. This review will help scientific communities in thermo-tolerance wheat cultivars and new emerging strategies to mitigate the deleterious impact of heat stress.

PELOTA and HBS1 suppress co-translational messenger RNA decay in Arabidopsis

Various messenger RNA (mRNA) decay mechanisms play major roles in controlling mRNA quality and quantity in eukaryotic organisms under different conditions. While it is known that the recently discovered co-translational mRNA decay (CTRD), the mechanism that allows mRNAs to be degraded while still being actively translated, is prevalent in yeast, humans, and various angiosperms, the regulation of this decay mechanism is less well studied. Moreover, it is still unclear whether this decay mechanism plays any role in the regulation of specific physiological processes in eukaryotes. Here, by re-analyzing the publicly available polysome profiling or ribosome footprinting and degradome sequencing datasets, we discovered that highly translated mRNAs tend to have lower co-translational decay levels. Based on this finding, we then identified Pelota and Hbs1, the translation-related ribosome rescue factors, as suppressors of co-translational mRNA decay in Arabidopsis. Furthermore, we found that Pelota and Hbs1 null mutants have lower germination rates compared to the wild-type plants, implying that proper regulation of co-translational mRNA decay is essential for normal developmental processes. In total, our study provides further insights into the regulation of CTRD in Arabidopsis and demonstrates that this decay mechanism does play important roles in Arabidopsis physiological processes.

A plant protein farnesylation system in prokaryotic cells reveals Arabidopsis AtJ3 produced and farnesylated in E. coli maintains its function of protecting proteins from heat inactivation

BACKGROUND

Protein farnesylation involves the addition of a 15-carbon polyunsaturated farnesyl group to proteins whose C-terminus ends with a CaaX motif. This post-translational protein modification is catalyzed by a heterodimeric protein, i.e., farnesyltransferase (PFT), which is composed of an α and a β subunit. Protein farnesylation in plants is of great interest because of its important roles in the regulation of plant development, responses to environmental stresses, and defense against pathogens. The methods traditionally used to verify whether a protein is farnesylated often require a specific antibody and involve isotope labeling, a tedious and time-consuming process that poses hazardous risks.

RESULTS

Since protein farnesylation does not occur in prokaryotic cells, we co-expressed a known PFT substrate (i.e., AtJ3) and both the α and β subunits of Arabidopsis PFT in E. coli in this study. Farnesylation of AtJ3 was detected using electrophoretic mobility using SDS-PAGE and confirmed using mass spectrometry. AtJ3 is a member of the heat shock protein 40 family and interacts with Arabidopsis HSP70 to protect plant proteins from heat-stress-induced denaturation. A luciferase-based protein denaturation assay demonstrated that farnesylated AtJ3 isolated from E. coli maintained this ability. Interestingly, farnesylated AtJ3 interacted with E. coli HSP70 as well and enhanced the thermotolerance of E. coli. Meanwhile, AtFP3, another known PFT substrate, was farnesylated when co-expressed with AtPFTα and AtPFTβ in E. coli. Moreover, using the same strategy to co-express rice PFT α and β subunit and a potential PFT target, it was confirmed that OsDjA4, a homolog of AtJ3, was farnesylated.

CONCLUSION

We developed a protein farnesylation system for E. coli and demonstrated its applicability and practicality in producing functional farnesylated proteins from both mono- and dicotyledonous plants.

A dynamic phosphoproteomic analysis provides insight into the C4 plant maize (Zea mays L.) response to natural diurnal changes

As sessile organisms, plants need to respond to rapid changes in numerous environmental factors, mainly diurnal changes of light, temperature, and humidity. Maize is the world's most grown crop, and as a C4 plant it exhibits high photosynthesis capacity, reaching the highest rate of net photosynthesis at midday; that is, there is no "midday depression." Revealing the physiological responses to diurnal changes and underlying mechanisms will be of great significance for guiding maize improvement efforts. In this study, we collected maize leaf samples and analyzed the proteome and phosphoproteome at nine time points during a single day/night cycle, quantifying 7424 proteins and 5361 phosphosites. The new phosphosites identified in our study increased the total maize phosphoproteome coverage by 8.5%. Kinase-substrate network analysis indicated that 997 potential substrates were phosphorylated by 20 activated kinases. Through analysis of proteins with significant changes in abundance and phosphorylation, we found that the response to a heat stimulus involves a change in the abundance of numerous proteins. By contrast, the high light at noon and rapidly changing light conditions induced changes in the phosphorylation level of proteins involved in processes such as chloroplast movement, photosynthesis, and C4 pathways. Phosphorylation is involved in regulating the activity of large number of enzymes; for example, phosphorylation of S55 significantly enhanced the activity of maize phosphoenolpyruvate carboxykinase1 (ZmPEPCK1). Overall, the database of dynamic protein abundance and phosphorylation we have generated provides a resource for the improvement of C4 crop plants.

The Re-Localization of Proteins to or Away from Membranes as an Effective Strategy for Regulating Stress Tolerance in Plants

The membranes of plant cells are dynamic structures composed of phospholipids and proteins. Proteins harboring phospholipid-binding domains or lipid ligands can localize to membranes. Stress perception can alter the subcellular localization of these proteins dynamically, causing them to either associate with or detach from membranes. The mechanisms behind the re-localization involve changes in the lipidation state of the proteins and interactions with membrane-associated biomolecules. The functional significance of such re-localization includes the regulation of molecular transport, cell integrity, protein folding, signaling, and gene expression. In this review, proteins that re-localize to or away from membranes upon abiotic and biotic stresses will be discussed in terms of the mechanisms involved and the functional significance of their re-localization. Knowledge of the re-localization mechanisms will facilitate research on increasing plant stress adaptability, while the study on re-localization of proteins upon stresses will further our understanding of stress adaptation strategies in plants.

Engineering Abiotic Stress Tolerance in Crop Plants through CRISPR Genome Editing

Environmental abiotic stresses challenge food security by depressing crop yields often exceeding 50% of their annual production. Different methods, including conventional as well as genomic-assisted breeding, mutagenesis, and genetic engineering have been utilized to enhance stress resilience in several crop species. Plant breeding has been partly successful in developing crop varieties against abiotic stresses owning to the complex genetics of the traits as well as the narrow genetic base in the germplasm. Irrespective of the fact that genetic engineering can transfer gene(s) from any organism(s), transgenic crops have become controversial mainly due to the potential risk of transgene-outcrossing. Consequently, the cultivation of transgenic crops is banned in certain countries, particularly in European countries. In this scenario, the discovery of the CRISPR tool provides a platform for producing transgene-free genetically edited plants-similar to the mutagenized crops that are not extensively regulated such as genetically modified organisms (GMOs). Thus, the genome-edited plants without a transgene would likely go into the field without any restriction. Here, we focused on the deployment of CRISPR for the successful development of abiotic stress-tolerant crop plants for sustaining crop productivity under changing environments.

Physiological and transcription level responses of microalgae Auxenochlorella protothecoides to cold and heat induced oxidative stress

Temperature is a crucial factor affecting microalgae CO₂ capture and utilization. However, an in-depth understanding of how microalgae respond to temperature stress is still unclear. In particular, the regulation mechanism under opposite temperature (heat and cold) stress had not yet been reported. In this study, the physicochemical properties and transcription level of related genes of microalgae Auxenochlorella protothecoides UTEX 2341 under heat and cold stress were investigated. Heat stress (Hs) caused a drastic increase of reactive oxygen species (ROS) in UTEX 2341. As key elements responded to Hs, superoxide dismutase (SOD) enzyme increased by 150%, 70%, and 30% in activity, and nitric oxide (NO) grew by 409.6%, 212.5%, and 990.4% in content compared with the control at 48 h, 96 h, 168 h. Under cold stress (Cs), ROS increased in the early stage and decreased in the later stage. As key factors responded to Cs, proline (Pro) increased respectively by 285%, 383%, and 81% in content, and heat shock transcriptional factor HSFA1d increased respectively by 161%, 71%, and 204% in transcript level compared with the control at 48 h, 96 h, 168 h. Furthermore, the transcript level of antioxidant enzymes or antioxidant coding genes was consistent with the changing trend of enzymes activity or antioxidant content. Notably, both glutathione (GSH) and heat shock protein 97 (hsp 97) were up-regulated in response to Hs and Cs. In conclusion, GSH and hsp 97 were the core elements of UTEX 2341 in response to both Hs and Cs. SOD and NO were the key elements that responded to Hs, while proline and HSFA1d were the key elements that responded to Cs. This study provided a basis for the understanding of the response mechanism of microalgae under temperature stress and the improvement of the microalgae tolerance to temperature stress.

How do plants feel the heat and survive?

Climate change is increasingly affecting the quality of life of organisms on Earth. More frequent, extreme, and lengthy heat waves are contributing to the sixth mass extinction of complex life forms in the Earth's history. From an anthropocentric point of view, global warming is a major threat to human health because it also compromises crop yields and food security. Thus, achieving agricultural productivity under climate change calls for closer examination of the molecular mechanisms of heat-stress resistance in model and crop plants. This requires a better understanding of the mechanisms by which plant cells can sense rising temperatures and establish effective molecular defenses, such as molecular chaperones and thermoprotective metabolites, as reviewed here, to survive extreme diurnal variations in temperature and seasonal heat waves.

Effect of Climate on Volatile Metabolism in 'Red Globe' Grapes (Vitis vinifera L.) during Fruit Development

With unique flavor and nutritional value, grapes are popular for eating and for the byproducts obtained in their processing. This study cultivated a popular grape variety, ‘Red Globe’, in two regions with different climates to investigate the discrepancies in their volatiles in response to climate. Saccharides, organic acids and transcriptomic and volatile metabolic analyses were studied separately via GC-FID, RNA sequencing and GC-MS/MS methods during the development of grape berries. In total, 83 volatiles were determined in samples, with (E)-2-hexenal the most abundant. Fatty acid derivatives and terpenoids in grapes showed discrepancies in different climates, and some of them were correlated to specific transcription factors. VvWRKY22 was influenced by climate conditions and was relative to saccharide accumulation. MYB-related transcription factors (TFs) were highly correlated with volatiles that accumulated during fruit ripening, especially decanal. Terpenoids showed correlations with a gene module that contained ERFs and HSFs. The findings support the hypothesis that fruit maturity and volatile formations vary in grape berries under different climates. Moreover, specific TFs could participate in volatile accumulations. The given results not only serve to enrich theoretical knowledge on the regulatory mechanism of volatiles in grapes, but also provide guidance for enhancing grape flavor and aroma by modulating cultivational conditions.