Carotenoid biosynthesis genes LcLCYB, LcLCYE, and LcBCH from wolfberry confer increased carotenoid content and improved salt tolerance in tobacco.

Carotenoids play essential roles in plant growth and development and provide plants with a tolerance to a series of abiotic stresses. In this study, the function and biological significance of lycopene ß-cyclase, lycopene ε-cyclase, and ß-carotene hydroxylase, which are responsible for the modification of the tetraterpene skeleton procedure, were isolated from Lycium chinense and analyzed. The overexpression of lycopene ß-cyclase, lycopene ε-cyclase, and ß-carotene hydroxylase promoted the accumulation of total carotenoids and photosynthesis enhancement, reactive oxygen species scavenging activity, and proline content of tobacco seedlings after exposure to the salt stress. Furthermore, the expression of the carotenoid biosynthesis genes and stress-related genes (ascorbate peroxidase, catalase, peroxidase, superoxide dismutase, and pyrroline-5-carboxylate reductase) were detected and showed increased gene expression level, which were strongly associated with the carotenoid content and reactive oxygen species scavenging activity. After exposure to salt stress, the endogenous abscisic acid content was significantly increased and much higher than those in control plants. This research contributes to the development of new breeding aimed at obtaining stronger salt tolerance plants with increased total carotenoids and vitamin A content.

A new point mutation in the HC-Pro of potato virus Y is involved in tobacco vein necrosis.

Tobacco vein necrosis (TVN) is a complex phenomenon regulated by different genetic determinants mapped in the HC-Pro protein (amino acids N330, K391 and E410) and in two regions of potato virus Y (PVY) genome, corresponding to the cytoplasmic inclusion (CI) protein and the nuclear inclusion protein a-protease (NIa-Pro), respectively. A new determinant of TVN was discovered in the MK isolate of PVY which, although carried the HC-Pro determinants associated to TVN, did not induce TVN. The HC-Pro open reading frame (ORF) of the necrotic infectious clone PVY N605 was replaced with that of the non-necrotic MK isolate, which differed only by one amino acid at position 392 (T392 instead of I392). The cDNA clone N605_MKHCPro inoculated in tobacco induced only weak mosaics at the systemic level, demostrating that the amino acid at position 392 is a new determinant for TVN. No significant difference in accumulation in tobacco was observed between N605 and N605_MKHCPro. Since phylogenetic analyses showed that the loss of necrosis in tobacco has occurred several times independently during PVY evolution, these repeated evolutions strongly suggest that tobacco necrosis is a costly trait in PVY.

Salivary Protein Cyclin-Dependent Kinase-like from Grain Aphid Sitobion avenae Suppresses Wheat Defense Response and Enhances Aphid Adaptation.

Aphids are insect pests that suck phloem sap and introduce salivary proteins into plant tissues through saliva secretion. The effector of salivary proteins plays a key role in the modulation of host plant defense responses and enhancing aphid host adaptation. Based on previous transcriptome sequencing results, a candidate effector cyclin-dependent kinase-like (CDK) was identified from the grain aphid Sitobion avenae. In this study, the function of SaCDK in wheat defense response and the adaptation of S. avenae was investigated. Our results showed that the transient overexpression of SaCDK in tobacco Nicotiana benthamiana suppressed cell death triggered by mouse pro-apoptotic protein-BAX or Phytophthora infestans PAMP-INF1. SaCDK, delivered into wheat cells through a Pseudomonas fluorescens-mediated bacterial type III secretion system, suppressed callose deposition in wheat seedlings, and the overexpression of SaCDK in wheat significantly decreased the expression levels of salicylic acid and jasmonic acid signaling pathway-related genes phenylalanine ammonia lyase (PAL), pathogenesis-related 1 protein (PR1), lipoxygenase (LOX) and Ω-3 fatty acid desaturase (FAD). In addition, aphid bioassay results showed that the survival and fecundity of S. avenae were significantly increased while feeding on the wheat plants carrying SaCDK. Taken together, our findings demonstrate that the salivary protein SaCDK is involved in inhibiting host defense response and improving its host adaptation, which lays the foundation to uncover the mechanism of the interaction of cereal aphids and host plants.

Unraveling a Small Secreted Peptide SUBPEP3 That Positively Regulates Salt-Stress Tolerance in Pyrus betulifolia.

Small secreted peptides (SSPs) play important roles in regulating plants' growth and development in response to external stimulus, but the genes and functions of SSPs in many species are still unknown. Therefore, it is particularly significant to characterize and annotate SSP genes in plant genomes. As a widely used stock of pears, Pyrus betulifolia has strong resistance to biotic and abiotic stresses. In this study, we analyzed the SSPs genes in the genome of P. betulifolia according to their characteristics and homology. A total of 1195 SSP genes were identified, and most of them are signaling molecules. Among these, we identified a new SSP, subtilase peptide 3 (SUBPEP3), which derived from the PA region of preSUBPEP3, increasing the expression level under salt stress. Both adding synthetic peptide SUBPEP3 to the culture medium of pears and the overexpression of SUBPEP3 in tobacco can improve the salt tolerance of plants. In summary, we annotated the SSP genes in the P. betulifolia genome and identified a small secreted peptide SUBPEP3 that regulates the salt tolerance of P. betulifolia, which provides an important theoretical basis for further revealing the function of SSPs.

Control of Sclerotinia sclerotiorum via an RNA interference (RNAi)-mediated targeting of SsPac1 and SsSmk1.

MAIN CONCLUSION: The study evaluates the potential of Spray-Induced Gene Silencing and Host-Induced Gene Silencing for sustainable crop protection against the broad-spectrum necrotrophic fungus Sclerotinia sclerotiorum. Sclerotinia sclerotiorum (Lib.) de Bary, an aggressive ascomycete fungus causes white rot or cottony rot on a broad range of crops including Brassica juncea. The lack of sustainable control measures has necessitated biotechnological interventions such as RNA interference (RNAi) for effective pathogen control. Here we adopted two RNAi-based strategies-Spray-Induced Gene Silencing (SIGS) and Host-Induced Gene Silencing (HIGS) to control S. sclerotiorum. SIGS was successful in controlling white rot on Nicotiana benthamiana and B. juncea by targeting SsPac1, a pH-responsive transcription factor and SsSmk1, a MAP kinase involved in fungal development and pathogenesis. Topical application of dsRNA targeting SsPac1 and SsSmk1 delayed infection initiation and progression on B. juncea. Further, altered hyphal morphology and reduced radial growth were also observed following dsRNA application. We also explored the impact of stable dsRNA expression in A. thaliana against S. sclerotiorum. In this report, we highlight the utility of RNAi as a biofungicide and a tool for preliminary functional genomics.

Design, Synthesis, and Biological Evaluation of Pyridazinone-Containing Derivatives As Novel Protoporphyrinogen IX Oxidase Inhibitor.

Protoporphyrinogen IX oxidase (PPO, E.C. 1.3.3.4) plays a pivotal role in chlorophyll biosynthesis in plants, making it a prime target for herbicide development. In this study, we conducted an investigation aimed at discovering PPO-inhibiting herbicides. Through this endeavor, we successfully identified a series of novel compounds based on the pyridazinone scaffold. Following structural optimization and biological assessment, compound 10ae, known as ethyl 3-((6-fluoro-5-(6-oxo-4-(trifluoromethyl)pyridazin-1(6H)-yl)benzo[d]thiazol-2-yl)thio)propanoate, emerged as a standout performer. It exhibited robust activity against Nicotiana tabacum PPO (NtPPO) with an inhibition constant (Ki) value of 0.0338 µM. Concurrently, we employed molecular simulations to obtain further insight into the binding mechanism with NtPPO. Additionally, another compound, namely, ethyl 2-((6-fluoro-5-(5-methyl-6-oxo-4-(trifluoromethyl)pyridazin-1(6H)-yl)benzo[d]thiazol-2-yl)thio)propanoate (10bh), demonstrated broad-spectrum and highly effective herbicidal properties against all six tested weeds (Leaf mustard, Chickweed, Chenopodium serotinum, Alopecurus aequalis, Poa annua, and Polypogon fugax) at the dosage of 150 g a.i./ha through postemergence application in a greenhouse. This work identified a novel lead compound (10bh) that showed good activity in vitro and excellent herbicidal activity in vivo and had promising prospects as a new PPO-inhibiting herbicide lead.

Cytokinin-deficient Chlamydomonas reinhardtii CRISPR-Cas9 mutants show reduced ability to prime resistance of tobacco against bacterial infection.

Although microalgae have only recently been recognized as part of the plant and soil microbiome, their application as biofertilizers has a tradition in sustainable crop production. Under consideration of their ability to produce the plant growth-stimulating hormone cytokinin (CK), known to also induce pathogen resistance, we have assessed the biocontrol ability of CK-producing microalgae. All pro- and eukaryotic CK-producing microalgae tested were able to enhance the tolerance of tobacco against Pseudomonas syringae pv. tabaci (PsT) infection. Since Chlamydomonas reinhardtii (Cre) proved to be the most efficient, we functionally characterized its biocontrol ability. We employed the CRISPR-Cas9 system to generate the first knockouts of CK biosynthetic genes in microalgae. Specifically, we targeted Cre Lonely Guy (LOG) and isopentenyltransferase (IPT) genes, the key genes of CK biosynthesis. While Cre wild-type exhibits a strong protection, the CK-deficient mutants have a reduced ability to induce plant defence. The degree of protection correlates with the CK levels, with the IPT mutants showing less protection than the LOG mutants. Gene expression analyses showed that Cre strongly stimulates tobacco resistance through defence gene priming. This study functionally verifies that Cre primes defence responses with CK, which contributes to the robustness of the effect. This work contributes to elucidate microalgae-mediated plant defence priming and identifies the role of CKs. In addition, these results underscore the potential of CK-producing microalgae as biologicals in agriculture by combining biofertilizer and biocontrol ability for sustainable and environment-friendly crop management.

The cAMP-dependent phosphorylation footprint in response to heat stress.

KEY MESSAGE: cAMP modulates the phosphorylation status of highly conserved phosphosites in RNA-binding proteins crucial for mRNA metabolism and reprogramming in response to heat stress. In plants, 3',5'-cyclic adenosine monophosphate (3',5'-cAMP) is a second messenger that modulates multiple cellular targets, thereby participating in plant developmental and adaptive processes. Although its role in ameliorating heat-related damage has been demonstrated, mechanisms that govern cAMP-dependent responses to heat have remained elusive. Here we analyze the role cAMP-dependent phosphorylation during prolonged heat stress (HS) with a view to gain insight into processes that govern plant responses to HS. To do so, we performed quantitative phosphoproteomic analyses in Nicotiana tabacum Bright Yellow-2 cells grown at 27 °C or 35 °C for 3 days overexpressing a molecular "sponge" that reduces free intracellular cAMP levels. Our phosphorylation data and analyses reveal that the presence of cAMP is an essential factor that governs specific protein phosphorylation events that occur during prolonged HS in BY-2 cells. Notably, cAMP modulates HS-dependent phosphorylation of proteins that functions in mRNA processing, transcriptional control, vesicular trafficking, and cell cycle regulation and this is indicative for a systemic role of the messenger. In particular, changes of cAMP levels affect the phosphorylation status of highly conserved phosphosites in 19 RNA-binding proteins that are crucial during the reprogramming of the mRNA metabolism in response to HS. Furthermore, phosphorylation site motifs and molecular docking suggest that some proteins, including kinases and phosphatases, are conceivably able to directly interact with cAMP thus further supporting a regulatory role of cAMP in plant HS responses.

A functional study reveals CsNAC086 regulated the biosynthesis of flavonols in Camellia sinensis.

MAIN CONCLUSION: CsNAC086 was found to promote the expression of CsFLS, thus promoting the accumulation of flavonols in Camellia sinensis. Flavonols, the main flavonoids in tea plants, play an important role in the taste and quality of tea. In this study, a NAC TF gene CsNAC086 was isolated from tea plants and confirmed its regulatory role in the expression of flavonol synthase which is a key gene involved in the biosynthesis of flavonols in tea plant. Yeast transcription-activity assays showed that CsNAC086 has self-activation activity. The transcriptional activator domain of CsNAC086 is located in the non-conserved C-terminal region (positions 171-550), while the conserved NAC domain (positions 1-170) does not have self-activation activity. Silencing the CsNAC086 gene using antisense oligonucleotides significantly decreased the expression of CsFLS. As a result, the concentration of flavonols decreased significantly. In overexpressing CsNAC086 tobacco leaves, the expression of NtFLS was significantly increased. Compared with wild-type tobacco, the flavonols concentration increased. Yeast one-hybrid assays showed CsNAC086 did not directly regulate the gene expression of CsFLS. These findings indicate that CsNAC086 plays a role in regulating flavonols biosynthesis in tea plants, which has important implications for selecting and breeding of high-flavonols-concentration containing tea-plant cultivars.

Early-life exposure to tobacco, genetic susceptibility, and accelerated biological aging in adulthood.

Early-life tobacco exposure serves as a non-negligible risk factor for aging-related diseases. To understand the underlying mechanisms, we explored the associations of early-life tobacco exposure with accelerated biological aging and further assessed the joint effects of tobacco exposure and genetic susceptibility. Compared with those without in utero exposure, participants with in utero tobacco exposure had an increase in Klemera-Doubal biological age (KDM-BA) and PhenoAge acceleration of 0.26 and 0.49 years, respectively, but a decrease in telomere length of 5.34% among 276,259 participants. We also found significant dose-response associations between the age of smoking initiation and accelerated biological aging. Furthermore, the joint effects revealed that high-polygenic risk score participants with in utero exposure and smoking initiation in childhood had the highest accelerated biological aging. There were interactions between early-life tobacco exposure and age, sex, deprivation, and diet on KDM-BA and PhenoAge acceleration. These findings highlight the importance of reducing early-life tobacco exposure to improve healthy aging.

The 6-kilodalton peptide 1 in plant viruses of the family Potyviridae is a viroporin.

Potyviridae, the largest family of plant RNA viruses, includes many important pathogens that significantly reduce the yields of many crops worldwide. In this study, we report that the 6-kilodalton peptide 1 (6K1), one of the least characterized potyviral proteins, is an endoplasmic reticulum-localized protein. AI-assisted structure modeling and biochemical assays suggest that 6K1 forms pentamers with a central hydrophobic tunnel, can increase the cell membrane permeability of Escherichia coli and Nicotiana benthamiana, and can conduct potassium in Saccharomyces cerevisiae. An infectivity assay showed that viral proliferation is inhibited by mutations that affect 6K1 multimerization. Moreover, the 6K1 or its homologous 7K proteins from other viruses of the Potyviridae family also have the ability to increase cell membrane permeability and transmembrane potassium conductance. Taken together, these data reveal that 6K1 and its homologous 7K proteins function as viroporins in viral infected cells.

'Candidatus Phytoplasma mali' SAP11-Like protein modulates expression of genes involved in energy production, photosynthesis, and defense in Nicotiana occidentalis leaves.

BACKGROUND: 'Candidatus Phytoplasma mali', the causal agent of apple proliferation disease, exerts influence on its host plant through various effector proteins, including SAP11CaPm which interacts with different TEOSINTE BRANCHED1/ CYCLOIDEA/ PROLIFERATING CELL FACTOR 1 and 2 (TCP) transcription factors. This study examines the transcriptional response of the plant upon early expression of SAP11CaPm. For that purpose, leaves of Nicotiana occidentalis H.-M. Wheeler were Agrobacterium-infiltrated to induce transient expression of SAP11CaPm and changes in the transcriptome were recorded until 5 days post infiltration. RESULTS: The RNA-seq analysis revealed that presence of SAP11CaPm in leaves leads to downregulation of genes involved in defense response and related to photosynthetic processes, while expression of genes involved in energy production was enhanced. CONCLUSIONS: The results indicate that early SAP11CaPm expression might be important for the colonization of the host plant since phytoplasmas lack many metabolic genes and are thus dependent on metabolites from their host plant.

Tobacco Smoke Condensate Induces Morphologic Changes in Human Papillomavirus-Positive Cervical Epithelial Cells Consistent with Epithelial to Mesenchymal Transition (EMT) with Activation of Receptor Tyrosine Kinases and Regulation of TGFB.

High-risk human papillomavirus (HR-HPV; HPV-16) and cigarette smoking are associated with cervical cancer (CC); however, the underlying mechanism(s) remain unclear. Additionally, the carcinogenic components of tobacco have been found in the cervical mucus of women smokers. Here, we determined the effects of cigarette smoke condensate (CSC; 3R4F) on human ectocervical cells (HPV-16 Ect/E6E7) exposed to CSC at various concentrations (10-6-100 µg/mL). We found CSC (10-3 or 10 µg/mL)-induced proliferation, enhanced migration, and histologic and electron microscopic changes consistent with EMT in ectocervical cells with a significant reduction in E-cadherin and an increase in the vimentin expression compared to controls at 72 h. There was increased phosphorylation of receptor tyrosine kinases (RTKs), including Eph receptors, FGFR, PDGFRA/B, and DDR2, with downstream Ras/MAPK/ERK1/2 activation and upregulation of common EMT-related genes, TGFB SNAI2, PDGFRB, and SMAD2. Our study demonstrated that CSC induces EMT in ectocervical cells with the upregulation of EMT-related genes, expression of protein biomarkers, and activation of RTKs that regulate TGFB expression, and other EMT-related genes. Understanding the molecular pathways and environmental factors that initiate EMT in ectocervical cells will help delineate molecular targets for intervention and define the role of EMT in the initiation and progression of cervical intraepithelial neoplasia and CC.

Reinforcing and adverse observable effects of nicotine and minor tobacco alkaloids in squirrel monkeys.

The most prevalent psychoactive chemical in tobacco smoke is nicotine, which has been shown to maintain tobacco consumption as well as cause acute adverse effects at high doses, like nausea and emesis. Recent studies in laboratory animals have suggested that many non-nicotine constituents of tobacco smoke (e.g., minor tobacco alkaloids) may also contribute to tobacco's overall reinforcing and adverse effects. Here, we used intravenous (IV) self-administration (n = 3) and observation (n = 4) procedures in squirrel monkeys to, respectively, compare the reinforcing and adverse observable effects of nicotine and three prominent minor tobacco alkaloids, nornicotine, anatabine, and myosmine. In self-administration studies, male squirrel monkeys were trained to respond under a second-order fixed-interval schedule of reinforcement and dose-effects functions for nicotine and each of the minor tobacco alkaloids nornicotine, anatabine, and mysomine were determined. Observation studies were conducted in a different group of male squirrel monkeys to quantify the ability of nicotine, nornicotine, anatabine, and mysomine to produce adverse overt effects, including hypersalivation, emesis, and tremors. Results show that nicotine and to a lesser extent nornicotine were readily self-administered, whereas anatabine and myosmine were not. In observation studies, all minor tobacco alkaloids produced adverse observable effects that were either comparable or more pronounced than nicotine. Collectively, the present results showing that nicotine and the minor tobacco alkaloids nornicotine, anatabine, and myosmine produce differential reinforcing and acute adverse observable effects in monkeys provides further evidence that these constituents may differently contribute to the psychopharmacological and adverse effects of tobacco consumption.

CIP1, a CIPK23-interacting transporter, is implicated in Cd tolerance and phytoremediation.

Environmental pollution from cadmium (Cd) presents a serious threat to plant growth and development. Therefore, it's crucial to find out how plants resist this toxic metal to develop strategies for remediating Cd-contaminated soils. In this study, we identified CIP1, a transporter protein, by screening interactors of the protein kinase CIPK23. CIP1 is located in vesicles membranes and can transport Cd2+ when expressed in yeast cells. Cd stress specifically induced the accumulation of CIP1 transcripts and functional proteins, particularly in the epidermal cells of the root tip. CIKP23 could interact directly with the central loop region of CIP1, phosphorylating it, which is essential for the efficient transport of Cd2+. A loss-of-function mutation of CIP1 in wild-type plants led to increased sensitivity to Cd stress. Conversely, tobacco plants overexpressing CIP1 exhibited improved Cd tolerance and increased Cd accumulation capacity. Interestingly, this Cd accumulation was restricted to roots but not shoots, suggesting that manipulating CIP1 does not risk Cd contamination of plants' edible parts. Overall, this study characterizes a novel Cd transporter, CIP1, with potential to enhance plant tolerance to Cd toxicity while effectively eliminating environmental contamination without economic losses.

Biomass ash as soil fertilizers: Supercharging biomass accumulation by shifting auxin distribution.

Growing quantities of biomass ashes (phyto-ashs) are currently produced worldwide due to the increasing biomass consumption in energy applications. Utilization of phyto-ash in agriculture is environmentally friendly solution. However, mechanisms involving the coordination of carbon metabolism and distribution in plants and soil amendment are not well known. In the present study, tobacco plants were chemically-fertilized with or without 2‰ phyto-ash addition. The control had sole chemical fertilizer; for two phyto-ash treatments, the one (T1) received comparable levels of nitrogen, phophorus, and potassium from phyto-ash and fertilizers as the control and another (T2) had 2‰ of phyto-ash and the same rates of fertilizers as the control. Compared with the control, phyto-ash addition improved the soil pH from 5.94 to about 6.35; T2 treatment enhanced soil available potassium by 30% but no difference of other elements was recorded among three treatments. Importantly, bacterial (but not fungal) communities were significantly enriched by phyto-ash addition, with the rank of richness as: T2 > T1 > control. Consistent with amelioration of soil properties, phyto-ash promoted plant growth through enlarged leaf area and photosynthesis and induced outgrowth of lateral roots (LRs). Interestingly, increased auxin content was recorded in 2nd and 3rd leaves and roots under phyto-ash application, also with the rank level as T2 > T1 > control, paralleling with higher transcripts of auxin synthetic genes in the topmost leaf and stronger [3H]IAA activity under phyto-ash addition. Furthermore, exogenous application of analog exogenous auxin (NAA) restored leaf area, photosynthesis and LR outgrowth to the similar level as T2 treatment; conversely, application of auxin transport inhibitor (NPA) under T2 treatment retarded leaf and root development. We demonstrated that phyto-ash addition improved soil properties and thus facilitated carbon balance within plants and biomass accumulation in which shifting auxin distribution plays an important role.

Molecular evolution and characterization of type III polyketide synthase gene family in Aquilaria sinensis.

2-(2-Phenylethyl) chromone (PEC) and its derivatives are markers of agarwood formation and are also related to agarwood quality. However, the biosynthetic and regulatory mechanisms of PECs still remain mysterious. Several studies suggested that type III polyketide synthases (PKSs) contribute to PEC biosynthesis in Aquilaria sinensis. Furthermore, systematic studies on the evolution of PKSs in A. sinensis have rarely been reported. Herein, we comprehensively analyzed PKS genes from 12 plant genomes and characterized the AsPKSs in detail. A unique branch contained only AsPKS members was identified through evolutionary analysis, including AsPKS01 that was previously indicated to participate in PEC biosynthesis. AsPKS07 and AsPKS08, two tandem-duplicated genes of AsPKS01 and lacking orthologous genes in evolutionary models, were selected for their transient expression in the leaves of Nicotiana benthamiana. Subsequently, PECs were detected in the extracts of N. benthamiana leaves, suggesting that AsPKS07 and AsPKS08 promote PEC biosynthesis. The interaction between the promoters of AsPKS07, AsPKS08 and five basic leucine zippers (bZIPs) from the S subfamily indicated that their transcripts could be regulated by these transcription factors (TFs) and might further contribute to PECs biosynthesis in A. sinensis. Our findings provide valuable insights into the molecular evolution of the PKS gene family in A. sinensis and serve as a foundation for advancing PEC production through the bioengineering of gene clusters. Ultimately, this contribution is expected to shed light on the mechanism underlying agarwood formation.

Molecular mechanism of abscisic acid signaling response factor VcbZIP55 to promote anthocyanin biosynthesis in blueberry (Vaccinium corymbosum).

A high content of anthocyanin in blueberry (Vaccinium corymbosum) is an important indicator to evaluate fruit quality. Abscisic acid (ABA) can promote anthocyanin biosynthesis, but since the molecular mechanism is unclear, clarifying the mechanism will improve for blueberry breeding and cultivation regulation. VcbZIP55 regulating anthocyanin synthesis in blueberry were screened and mined using the published Isoform-sequencing, RNA-Seq and qRT-PCR at different fruit developmental stages. Blueberry genetic transformation and transgenic experiments confirmed that VcbZIP55 could promote anthocyanin biosynthesis in blueberry adventitious buds, tobacco leaves, blueberry leaves and blueberry fruit. VcbZIP55 responded to ABA signals and its expression was upregulated in blueberry fruit. In addition, using VcbZIP55 for Yeast one hybrid assay (Y1H) and transient expression in tobacco leaves demonstrated an interaction between VcbZIP55 and a G-Box motif on the VcMYB1 promoter to activate the expression of VcMYB1. This study will lay the theoretical foundation for the molecular mechanisms of phytohormone regulation responsible for anthocyanin synthesis and provide theoretical support for blueberry quality improvement.

Climate change and health: rethinking public health messaging for wildfire smoke and extreme heat co-exposures.

With the growing climate change crisis, public health agencies and practitioners must increasingly develop guidance documents addressing the public health risks and protective measures associated with multi-hazard events. Our Policy and Practice Review aims to assess current public health guidance and related messaging about co-exposure to wildfire smoke and extreme heat and recommend strengthened messaging to better protect people from these climate-sensitive hazards. We reviewed public health messaging published by governmental agencies between January 2013 and May 2023 in Canada and the United States. Publicly available resources were eligible if they discussed the co-occurrence of wildfire smoke and extreme heat and mentioned personal interventions (protective measures) to prevent exposure to either hazard. We reviewed local, regional, and national governmental agency messaging resources, such as online fact sheets and guidance documents. We assessed these resources according to four public health messaging themes, including (1) discussions around vulnerable groups and risk factors, (2) symptoms associated with these exposures, (3) health risks of each exposure individually, and (4) health risks from combined exposure. Additionally, we conducted a detailed assessment of current messaging about measures to mitigate exposure. We found 15 online public-facing resources that provided health messaging about co-exposure; however, only one discussed all four themes. We identified 21 distinct protective measures mentioned across the 15 resources. There is considerable variability and inconsistency regarding the types and level of detail across described protective measures. Of the identified 21 protective measures, nine may protect against both hazards simultaneously, suggesting opportunities to emphasize these particular messages to address both hazards together. More precise, complete, and coordinated public health messaging would protect against climate-sensitive health outcomes attributable to wildfire smoke and extreme heat co-exposures.