Stress Tolerance In Plants Research Articles

PP2 gene family in Phyllostachys edulis: identification, characterization, and expression profiles.

Phloem protein 2 (PP2), a dimeric lectin, is known for its involvement in plant responses to biotic and abiotic stresses. However, research on PP2 proteins in Moso bamboo is lacking. In this study, comprehensive genome-wide analysis of the PP2-like gene family was conducted in Moso bamboo (Phyllostachys edulis), which has a significant economic and ecological value. Using HMMER3 search and InterPro domain analysis, 23 PP2-like genes (PhePP2-1 to PhePP2-23) were identified in the P. edulis genome. These genes were distributed across 12 chromosomal scaffolds, with proteins ranging from 216 to 556 amino acids in length. Phylogenetic analysis, including 163 PP2 proteins from eight plant species, revealed six distinct groups, with Group III and Group V being the largest. Gene structure and motif analyses indicated conserved domains across the PhePP2 proteins. In addition, Cis-element analysis of the promoter regions highlighted their potential regulatory roles in hormone, stress, and light responses. Expression pattern analysis using RNA-seq data showed differential expression of PhePP2 genes under drought, salt, salicylic acid, and abscisic acid treatments, indicating their involvement in stress response pathways. Furthermore, qPCR validation in different tissues and organs of Moso bamboo confirmed the expression profiles of the selected PhePP2 genes. This study provides a comprehensive understanding of the functional roles of PP2-like genes in Moso bamboo and insights into their potential applications in enhancing stress tolerance and growth in plants.

Crucial role of fungi in environmentally sustainable agriculture

To produce more, better and safer food we must be able to do so while promoting the sustainable use of agricultural resources. The increase in agricultural production is currently through the use of pesticides, fertilizers, and developments in plant breeding and genetic skills. In naturally existing ecosystems, rhizospheric soils have biological living beings to favor the plant development, nutrient assimilation, stress tolerance, disease deterrence, carbon seizing and others. Fungi are among the most widely distributed organisms on Earth and are of great environmental importance. Mycorrhizal fungi, bacteria, actinomycetes, etc. solubilize nutrients and assist the plants in uptake by roots. Amongst them, vesicular/arbuscular mycorrhizal fungi (AMF) have key roles in the natural ecosystem, as the majority of the terrestrial plants form association with AMF. This symbiosis confers benefits directly to the host plant’s growth and development through the acquisition of phosphorus (P) and other mineral nutrients from the soil. They may also enhance the protection of plants against pathogens, increase plant diversity and have the potential to enhance plant growth under stressful environments. In this article, the sustainability and environmental aspects of agriculture, and the basic concepts of fungi will be reviewed to justify our point of view about the tremendous importance of fungi towards an environmentally sustainable agriculture.

Elucidating the protective role of manganese seed priming in mitigating lead-induced oxidative stress: enhancements in growth, grain yield, and antioxidant activities of wheat.

Lead (Pb) is known to be extremely toxic to plants and awfully affects growth and productivity by interacting with morphological, biochemical, and physiological processes. Micronutrients are considered to reduce ion toxicity and modify various physiological processes involved in oxidative stress tolerance in plants. Hence, the limited literature about the application of micronutrients, particularly manganese (Mn), under lead stress thus demands more investigations. To sort out the role of priming treatments of Mn (1.0 and 0.1mg/L) in lead stress (200mg/kg) induced oxidative stress tolerance in wheat cultivars (Anaj-17 and Akbar-19), current experiment was designed. The experiment was arranged with completely randomized design (CRD) with three replicates. The results explored the positive role of Mn priming in strengthening the antioxidant system with increased activities of antioxidants under Pb stress. Mn priming level (0.1mg/L) significantly increased the germination percentage, germination percentage, growth traits, grain yield per plant, shoot P, shoot Ca2+, and shoot K+ while decreasing the MDA and H2O2 levels, of Anaj-17 and Akbar-19 under Pb stress (200mg/kg). Seed priming levels of Mn further upgraded the antioxidant enzymatic activities and organic osmolytes such as proline, total phenolics, flavonoids, total soluble sugars, and glycine betaine, under Pb stress. Conclusively, the 0.1mg/L level of Mn priming and Akbar-19 cultivar has proven superior in lead detoxification under Pb-induced oxidative stress. Furthermore, the outcomes revealed more accumulation of Pb in the roots of wheat than in the shoots of both wheat cultivars and emphasized the use of lower Mn levels of 0.1mg/L as the best strategy in alleviating the toxic impacts of lead in wheat. However, the conduct of large field trials is a necessity of current scenario to study the molecular aspects and associated genes contributing Pb stress tolerance with priming application of Mn and other micronutrients.

Exploring the Synergistic Effects of Biostimulant and Hydrogel Combinations on Brinjal Growth: An Assessment of Growth Parameters

Background: This study at Lovely Professional University, Phagwara, Punjab, evaluates the combined effects of hydrogel and Arka Vegetable biostimulants on brinjal (Solanum melongena L.) production. Brinjal’s high water and nutrient needs make it sensitive to water scarcity and seasonal variations. Hydrogel enhances soil moisture retention, reducing irrigation needs, while Arka Vegetable biostimulants improve plant growth and stress tolerance. Using both together aims to optimize water management and plant health, addressing key challenges in brinjal cultivation. Methods: In the study, the hydrogel was applied during the sowing stage, while Arka Vegetable Special was sprayed twice, with a 15-day interval after transplanting. The treatment designated as V2H2 (5 g/L + 1.5 kg/acre) was utilized, where ‘V’ represents concentration in grams per liter and ‘H’ denotes application rate in kilograms per acre. This treatment is aimed at optimizing vegetative growth. Various levels of Arka Vegetable Special and hydrogel application were tested to observe their effects on growth characteristics. Result: The study’s findings revealed the effectiveness of the V2H2 treatment in enhancing vegetative growth. Application of Arka Vegetable Special and hydrogel at different levels significantly improved all the studied growth characteristics. This suggests the potential of integrating biostimulants and Hydrogel practices to optimize Brinjal production, offering a sustainable solution to meet year-round vegetable demand and mitigate water scarcity challenges in agricultural systems.

Decoding the Impact of a Bacterial Strain of Micrococcus luteus on Arabidopsis Growth and Stress Tolerance

Microbes produce various bioactive metabolites that can influence plant growth and stress tolerance. In this study, a plant growth-promoting rhizobacterium (PGPR), strain S14, was identified as Micrococcus luteus (designated as MlS14) using de novo whole-genome assembly. The MlS14 genome revealed major gene clusters for the synthesis of indole-3-acetic acid (IAA), terpenoids, and carotenoids. MlS14 produced significant amounts of IAA, and its volatile organic compounds (VOCs), specifically terpenoids, exhibited antifungal activity, suppressing the growth of pathogenic fungi. The presence of yellow pigment in the bacterial colony indicated carotenoid production. Treatment with MlS14 activated the expression of β-glucuronidase (GUS) driven by a promoter containing auxin-responsive elements. The application of MlS14 reshaped the root architecture of Arabidopsis seedlings, causing shorter primary roots, increased lateral root growth, and longer, denser root hairs; these characteristics are typically controlled by elevated exogenous IAA levels. MlS14 positively regulated seedling growth by enhancing photosynthesis, activating antioxidant enzymes, and promoting the production of secondary metabolites with reactive oxygen species (ROS) scavenging activity. Pretreatment with MlS14 reduced H2O2 and malondialdehyde (MDA) levels in seedlings under drought and heat stress, resulting in greater fresh weight during the post-stress period. Additionally, exposure to MlS14 stabilized chlorophyll content and growth rate in seedlings under salt stress. MlS14 transcriptionally upregulated genes involved in antioxidant defense and photosynthesis. Furthermore, genes linked to various hormone signaling pathways, such as abscisic acid (ABA), auxin, jasmonic acid (JA), and salicylic acid (SA), displayed increased expression levels, with those involved in ABA synthesis, using carotenoids as precursors, being the most highly induced. Furthermore, MlS14 treatment increased the expression of several transcription factors associated with stress responses, with DREB2A showing the highest level of induction. In conclusion, MlS14 played significant roles in promoting plant growth and stress tolerance. Metabolites such as IAA and carotenoids may function as positive regulators of plant metabolism and hormone signaling pathways essential for growth and adaptation to abiotic stress.

The role of gibberellin synthase gene VvGA2ox7 acts as a positive regulator to salt stress in Arabidopsis thaliana.

Soil salinity is an important environmental component affecting plant growth and yield, but high-salinity soils are a major constraint to the development of the grape industry. Previous studies have provided lines of evidence that gibberellins (GAs) play a significant regulatory role in plant responses to salt stress. However, it remains unclear whether GA2ox, a key enzyme that maintains the balance of bioactive gibberellins and intermediates in plants, is involved in the mechanism of salt stress tolerance in grapes. In this study, we found that GA2ox7 positively modulates salt stress via its ectopic expression in Arabidopsis thaliana. The GA2ox7 gene cloned from grape was a hydrophilic protein, its CDS length was 1002bp. Besides, VvGA2ox7 protein contained DIOX_N and 2OG-FeII_Oxy domains and was localized at the nucleus and cytoplasm. Yeast two-hybrid (Y2H) showed VvARCN1, VvB5R, VvRUB2, and VvCAR11 might be potential interaction proteins of VvGA2ox7. Compared with the wild type, overexpression of VvGA2ox7 in Arabidopsis thaliana enhanced antioxidant enzymatic activities and proline, chlorophyll, and ABA contents, and decreased relative electrical conductivity, malondialdehyde, and GA3 contents. Moreover, overexpression of VvGA2ox7 positively regulated the expression of salt stress response genes (KAT1, APX1, LEA, P5CS1, AVP1, CBF1), indicating that the VvGA2ox7 overexpression improved the salt stress tolerance of plants. Taken together, this investigation indicates that VvGA2ox7 may act as a positive regulator in response to salt stress and provide novel insights for a deeper understanding of the role of VvGA2ox7 in grapes.

Therapeutic potential and agricultural benefits of curcumin: a comprehensive review of health and sustainability applications

AbstractTurmeric (Curcuma longa L.), the plant from which curcumin is derived, is renowned for its wide range of therapeutic and agricultural benefits. Curcumin, the key bioactive compound, is highly valued for its potent anti-provocative, antioxidant, and antimicrobial properties, which contribute to its effectiveness in treating various human diseases and improving plant resilience to environmental stresses. The therapeutics potential of curcumin is notable owing its abilities to combat microbes act as an oxidant and reduce inflammation. Its effectiveness in treating a range of human disease such as tumor, cardiac problems, and brain degenerative ailments stems from its ability to modulate various cellular process and signaling pathways. Despite its low bioavailability, innovations in delivery system such as nanoparticles and liposomal formulations, have enhanced its therapeutic efficacy by improving solubility and systemic absorption. In agriculture, curcumin's antimicrobial properties provide a natural alternative to chemical pesticides, offering protection against pathogens and enhancing plant resilience to specific environmental stresses such as drought, salinity, and oxidative stress. Nanotechnology applications have furthered these benefits by facilitating the efficient uptake and distribution of curcumin within plant tissues, promoting growth and stress tolerance. This review also highlights curcumin's nutritional benefits, including its impact on gut health and metabolic syndrome. Synergistic interactions with dietary nutrients can amplify its health benefits, making it a valuable dietary supplement. However, ongoing research is needed to fully understand curcumin's mechanisms of action and long-term safety. Overall, curcumin holds promise as a versatile agent in both medical and agricultural fields, supporting sustainable practices and advancing health outcomes. Future research should focus on optimizing curcumin formulations and translating preclinical findings into clinical successes. Graphical abstract

Stilbene production as part of drought adaptation mechanisms in cultivated grapevine (Vitis vinifera L.) roots modulates antioxidant status.

Stilbenes, naturally occurring polyphenolic secondary metabolites, play a pivotal role in adaptation of various plant species to biotic and abiotic factors. Recently, increased attention has been directed toward their potential to enhance plant stress tolerance. We evaluated drought tolerance of three grapevine varieties grown with different levels of water deficit. Throughout, we studied physiological mechanisms associated with drought stress tolerance, particularly stilbene accumulation in root tissues, using HPLC. Additionally, we explored the possible relationship between antioxidant potential and stilbene accumulation in response to water deficit. The results underscore the detrimental impact of water deficit on grapevine growth, water status, and membrane stability index, while revealing varying tolerance among the studied genotypes. Notably, Syrah variety had superior drought tolerance, compared to Razegui and Muscat d'Italie grapes. Under severe water deficit, Syrah exhibited a substantial increase in levels of stilbenic compounds, such as t-resveratrol, t-piceatannol, t-ɛ-viniferin, and t-piceid, in root tissues compared to other genotypes. This increase was positively correlated with total antioxidant activity (TAA), emphasizing the active role of resveratrol and its derivatives in total antioxidant potential. This demonstratres the potential involvement of resveratrol and its derivatives in enhancing antioxidant status of the drought-tolerant Syrah grape variety. Our findings suggest that these stilbenes may function as valuable markers in grapevine breeding programs, offering novel insights for the sustainable cultivation of grapevines in water-limited environments.

Bcl-2-Associated Athanogene (BAG) Co-chaperones: Key Players in Multiple Abiotic and Biotic Stress Tolerance in Plants

Bcl-2-Associated Athanogene (BAG) Co-chaperones: Key Players in Multiple Abiotic and Biotic Stress Tolerance in Plants

Opinion: Smart nanofertilizers for growth enhancement and stress resilience in agriculture

Smart nanofertilizers (NFs) represent a promising frontier in agricultural technology, offering precise nutrient delivery and stress resilience to enhance crop growth and productivity while minimizing the environmental impact. This opinion article explores the potential of smart NFs in revolutionizing traditional fertilization practices and addressing the challenges facing modern agriculture. By harnessing the unique properties of nanomaterials, smart NFs including noble metal nanoparticles, green NFs, and novel NFs from industrial waste enable targeted nutrient delivery, enhanced nutrient use efficiency, and stress tolerance in plants. However, their widespread adoption faces regulatory, safety, and scalability challenges that require interdisciplinary collaboration and concerted efforts from stakeholders. Despite these hurdles, smart NFs hold immense promise for promoting sustainable agriculture and ensuring food security in frequently changing global climatic conditions.

Melatonin application enhances salt stress-induced decreases in minerals, betalains, and phenolic acids in beet (Beta vulgaris L.) cultivars.

Melatonin is a potentially active signaling molecule and plays a crucial role in regulating the growth and development of plants under stress conditions, alleviating oxidative damage, enhancing antioxidant defence mechanisms and regulating ion homeostasis. This study examined the effects of exogenous melatonin application on leaf biomass, ion concentrations, betalains, phenolic acid and endogenous melatonin contents comparing red beet (Beta vulgaris L. 'Ruby Queen' and 'Scarlet Supreme') and white beet ('Rodeo' and 'Ansa') cultivars under increasing salinity levels of 50, 150, and 250 mM NaCl. Exogenous melatonin increased salinity-induced reductions in fresh and dry weights and osmotic potential in leaves. Na+ concentrations rose significantly with increasing salinity, but cultivar-specific decreases were observed in K+ and Ca2+ concentrations. Additionally, melatonin application improved betalain, betanin and neobetanin contents induced by salt stress. Furthermore, melatonin application caused salt stress and cultivar-specific changes in phenolic acid contents e.g., ferulic acid, sinapic acid, or m-coumaric acid, in soluble free, ester- and glycoside-conjugated and cell wall-bound forms. In addition, antioxidant enzyme activities and compound contents increased significantly in the beets and were subsequently lowered in a cultivar-specific manner by salt stress + melatonin treatment. The current findings indicate that exogenous melatonin improved plant stress tolerance suppressing reactive oxygen species levels, increasing the antioxidant enzyme activities and compound contents and reducing the levels of Na+, maintaining an ionic homeostasis in the selected red and white sugar beet cultivars. It appears that melatonin application may help improve cultivar-specific salt tolerance by enhancing ion homeostasis and betalain and phenolic acid production levels in beets.

Physiology and transcriptome profiling reveal the drought tolerance of five grape varieties under high temperatures

The evaluation of plant stress tolerance and the screening of key regulatory genes under the combined stresses of high temperature and drought are important for the study of plant stress tolerance mechanisms. In this study, the drought tolerance of five grape varieties was evaluated under high-temperature conditions to screen key genes for further exploration of resistance mechanisms. By comparing and analysing the morphological characteristics and physiological indicators associated with the response of grapevines to drought stress and integrating them with the membership function to assess the strength of their drought tolerance, the order of drought tolerance was found to be as follows: 420A>110R>CS>fercal>188-08. To further analyse the mechanism of differences in drought tolerance, transcriptomic sequencing was performed on the drought-tolerant cultivar 420A, the drought-sensitive cultivar 188-08 and the control cultivar CS. The functional analysis of differential metabolic pathways indicated that the differentially expressed genes were enriched mainly in biological that 420A had higher antioxidant activity. Moreover, the transcription factors which differentially expressed were also analysed in the five grape varieties, and several genes, such as VvAGL15, VvLBD41, and VvMYB86, appeared to be closely related to drought tolerance, suggesting their potential involvement in the regulation of grapevine drought tolerance and their value in drought tolerance research.

MYB30-INTERACTING E3 LIGASE 1 regulates LONELY GUY 5-mediated cytokinin metabolism to promote drought tolerance in cotton

Abstract Ubiquitination plays important roles in modulating the abiotic stress tolerance of plants. Drought seriously restricts agricultural production, but how ubiquitination participates in regulating drought tolerance remains largely unknown. Here, we identified a drought-inducible gene, MYB30-INTERACTING E3 LIGASE 1 (GhMIEL1), which encodes a RING E3 ubiquitin ligase in cotton (Gossypium hirsutum). GhMIEL1 was strongly induced by polyethylene glycol (PEG-6000) and the phytohormone abscisic acid (ABA). Overexpression and knockdown of GhMIEL1 in cotton substantially enhanced and reduced drought tolerance, respectively. GhMIEL1 interacted with the MYB transcription factor GhMYB66 and could ubiquitinate and degrade it in vitro. GhMYB66 directly bound to the LONELY GUY 5 (GhLOG5) promoter, a gene encoding cytokinin riboside 5'-monophosphate phosphoribohydrolase, to repress its transcription. Overexpression of GhMIEL1 and silencing of GhMYB66 altered the homeostasis of cytokinin of plant roots, increased total root length and number of root tips, and enhanced plant drought tolerance. Conversely, silencing GhLOG5 decreased total root length and number of root tips and reduced plant drought tolerance. Our studies reveal that the GhMIEL1-GhMYB66-GhLOG5 module positively regulates drought tolerance in cotton, which deepens our understanding of plant ubiquitination-mediated drought tolerance and provides insights for improving drought tolerance.

Enhancing drought stress tolerance in horticultural plants through melatonin-mediated phytohormonal crosstalk.

Melatonin and melatonin-mediated phytohormonal crosstalk play a multifaceted role in improving drought stress tolerance via molecular mechanisms and biochemical interactions in horticultural plants. The physical, physiological, biochemical, and molecular characteristics of plants are all affected by drought stress. Crop yield and quality eventually decline precipitously as a result. A phytohormone, melatonin, controls several plant functions during drought stress. However, the interactions between melatonin and other phytohormones, particularly how they control plant responses to drought stress, have not been clearly explored. This review explores the effects of melatonin and particular phytohormones on improving plant tolerance to drought stress. Specifically, the key melatonin roles in improved photosynthetic performance, better antioxidant activities, up-regulated gene expression, increased plant growth, and yield, etc., during drought stress have been elucidated in this review. Furthermore, this review explains how the intricate networks of melatonin-mediated crosstalk phytohormones, such as IAA, BR, ABA, GA, JA, CK, ET, SA, etc., enable horticultural plants to tolerate drought stress. Thus, this research provides a better understanding of the role of phytohormones, mainly melatonin, elucidates phytohormonal cross-talks in drought stress response, and future perspectives of phytohormonal contributions in plant improvements including engineering plants for better drought stress tolerance via targeting melatonin interactions.

Seed Priming with Dynamically Transformed Selenium Nanoparticles to Enhance Salt Tolerance in Rice.

Seed priming with nanomaterials is an emerging approach for improving plant stress tolerance. Here, we demonstrated a mechanism for enhancing salt tolerance in rice under salt stress via priming with nonstimulatory nanoparticles such as selenium nanoparticles (SeNPs), distinct from stimulatory nanomaterials. Due to the dynamic transformation ability of SeNPs, SeNP priming could enhance rice salt tolerance by mediating the glutathione cycle to eliminate excess reactive oxygen species (ROS). During priming, SeNPs penetrated rice seeds and transitioned into a soluble form (99.9%) within the embryo endosperm. Subsequently, the soluble selenium (Se) was transported to rice roots and metabolized into various Se-related derivatives, including selenomethionine (SeMet), Na2SeO3 (Se IV), selenocysteine (SeCys2), and methylselenocysteine (MeSeCys). These derivatives significantly enhanced the root activities of key enzymes such as glutathione peroxidase (GSH-PX), glutathione reductase (GR), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) by 24.97%, 47.98%, 16.23%, 16.81%, and 14.82%, respectively, thus reinforcing the glutathione cycle and ROS scavenging pathways. Moreover, these alterations induced transcriptional changes in rice seedlings, with genes involved in signal transduction, transcription factors (TFs), ROS scavenging, and protein folding being upregulated, activating signal perception and self-repair mechanisms. These findings offer valuable insights for the agricultural application of nanomaterials.

Plant membrane transporters function under abiotic stresses: a review.

In the present review, we discussed the detailed signaling cascades via membrane transporters that confer plant tolerance to abiotic stresses and possible significant use in plant development for climate-resilient crops. Plant transporters play significant roles in nutrient uptake, cellular balance, and stress responses. They facilitate the exchange of chemicals and signals across the plant's membrane by signal transduction, osmotic adjustment, and ion homeostasis. Therefore, research into plant transporters is crucial for understanding the mechanics of plant stress tolerance. Transporters have potential applications in crop breeding for increased stress resistance. We discuss new results about various transporter families (ABC, MATE, NRAMP, NRT, PHT, ZIP), including their functions in abiotic stress tolerance and plant development. Furthermore, we emphasize the importance of transporters in plant responses to abiotic stresses such as drought, cold, salt, and heavy metal toxicity, low light, flooding, and nutrient deficiencies. We discuss the transporter pathways and processes involved in diverse plant stress responses. This review discusses recent advances in the role of membrane transporters in abiotic stress tolerance in Arabidopsis and other crops. The review contains the genes discovered in recent years and associated molecular mechanisms that improve plants' ability to survive abiotic stress and their possible future applications by integrating membrane transporters with other technologies.

Transcriptome-wide analysis reveal dynamic expression changes during endoplasmic reticulum stress in tomato

Endoplasmic reticulum (ER) stress is a cellular condition induced by environmental stressors. Transcriptomic approaches reveal the response of plants to ER stress and provide a broadened view. Tomato plants were treated with tunicamycin, and total RNA isolated from the tomato leaves was sequenced on an RNA-sequencing platform to be analyzed for differential expressions. A total of 856 differentially expressed genes (DEGs) were discovered in tunicamycin-treated tomato leaves. Upregulation of ER stress marker gene expressions was detected after 2h, while a prolonged ER stress downregulated most of the protein-coding genes. Pathways such as: response to stress, jasmonic acid mediated signaling, signal transduction regulation, plant hormone signal transduction, and protein processing in ER were enriched. Prolonged stress mostly resulted in reduced transcript levels, possibly related to a mechanism functioning to lower the load of nascent transcripts in the ER. Our findings emphasize the key role of JA-regulated signaling in tomato ER stress responses due to the differential expressions of the pathway components, along with other plant hormones and signaling-related or regulatory genes. ER stress being a common response to many stressors in plants, transcriptome data obtained here will provide for further studies of understanding plant stress tolerance or generating stress-resistant tomato plants.

Seasonal influence on tomato fruit metabolome profile: Implications for ABA signaling in multi-stress resilience

The increasing effects of climate change are leading to an increase in the number and intensity of extreme events, making it essential to study how plants respond to various stresses occurring simultaneously. A crucial regulator of plant responses to abiotic stress is abscisic acid (ABA), as its accumulation in response to stress leads to transcriptomic and metabolomic changes that contribute to plant stress tolerance. In the present study, we investigated how ABA, stress conditions (salinity, water deficit and their combination) and seasons (autumn-winter and spring-summer) regulate tomato fruit yield and metabolism using tomato wild type (WT) and the ABA-deficient flacca mutant (flc) under stress conditions in cold and warm seasons. Our results showed that the applied stresses did not have the same effect in the warm season as in the cold season. In WT plants, the levels of other flavonoids, lignans and other polyphenols were higher in summer fruits, whereas the levels of anthocyanins, flavanols, flavonols, phenolic acids and stilbenes were higher in winter fruits. Furthermore, the significant increase in anthocyanins and flavonols was associated with the combination of salinity + water deficit in both seasons. Additionally, under certain conditions, flc mutants showed an enrichment of the superclasses of benzenoids and organosulphur compounds. The synthesis of phenolic compounds in flc fruits was also significantly different compared to WT plants. Thus, the metabolic profile of tomato fruits varies significantly with endogenous ABA levels, season of cultivation and applied stress treatments, highlighting the multifactorial nature of plant responses to combined environmental factors.

Plant Rho GTPase ROP6 Is Essential for Manganese Homeostasis in Arabidopsis.

Manganese (Mn) is an indispensable mineral for plant growth and development. However, plants cultivated in acidic and poorly drained soils are vulnerable to Mn2+ toxicity due to its heightened increased bioavailability. Despite the crucial roles of the Rho of plant (ROP) GTPases in various cellular processes, their precise function in regulating Mn homeostasis remains elusive. In this study, we unveil a novel ROP6 GTPase signalling pathway that profoundly influences Mn phytotoxicity tolerance in Arabidopsis. Remarkably, the rop6 and dominant-negative ROP6 (rop6DN) mutant plants displayed a dramatically sensitive phenotype to Mn toxicity, whereas ROP6-overexpression and constitutively activated ROP6 (rop6CA) lines exhibited enhanced Mn stress tolerance. Immunoblot analysis corroborated that the ROP6 protein, especially the active form of ROP6, increased in abundance in the presence of high Mn levels. Further, we identified that ROP6 physically interacted and colocalized with Metal Tolerance Protein 8 (MTP8) in vivo. Mn transport complementation assays in yeast, combined with biochemical analyses, emphasized the essentiality of ROP6 for MTP8's transport activity. In addition, genetic analyses indicated that ROP6 acted upstream of MTP8 in the regulatory cascade. Collectively, our findings elucidate that ROP6 GTPase signalling positively modulates and enhances Mn stress tolerance in plants.

Evolutionary and Expression Analyses of the bZIP Family in Tea Plants (Camellia sinensis) and Functional Characterization of CsbZIP3/42/6 in Response to Environmental Stresses.

Basic leucine zipper (bZIP) transcription factors play crucial roles in various biological processes and responses to environmental stresses. However, the functions of the bZIP family in tea plants remain largely unexplored. Here, we identified 74 bZIP genes in tea plants (Camellia sinensis) and classified them into 12 phylogenetic groups, supported by analyses of conserved motifs and gene structures. Cis-element analysis provided insights into the potential roles of CsbZIP genes in phytohormone signaling and stress responses. Tissue-specific expression analysis demonstrated differential expression profiles of CsbZIP genes, suggesting their tissue- and stage-specific functions. Additionally, varying expression levels under different abiotic stresses indicated functional divergence of the CsbZIP family during the long-term evolution. Notably, CsbZIP3/42/6 were identified as positive regulators of drought and salt stress responses but negative regulators in response to pathogen infection, and CsbZIP42 could interact with CsbZIP3 and CsbZIP6 in regulating these environmental stresses. This study provides valuable information on potential applications for improving stress tolerance and overall plant health of tea plants.