Starch and Sucrose Metabolism and Plant Hormone Signaling Pathways Play Crucial Roles in Aquilegia Salt Stress Adaption

Overexpression of the GmERF071 gene confers resistance to soybean cyst nematode in soybean

Soybean cyst nematode (SCN) is one of the most harmful pests, causing major reductions in soybean yield globally. The validation and functional characterization of SCN resistance genes are crucial to improving soybean yield worldwide. Herein, we describe an SCN resistance gene, GmERF071 (Glyma.19g262700). GmERF071 is a hydrophilic, unstable protein with an AP2/ERF subfamily ethylene response transcription factor domain, which is localized in the nucleus. Overexpression of GmERF071 enhanced SCN resistance in the soybean stable genetic transformation and root systems. RNA-seq analysis revealed 394 upregulated and 132 downregulated differentially expressed genes (DEGs) in GmERF071 overexpression transgenic plants. The DEGs participated in plant-pathogen interactions, mitogen-activated protein kinase signaling, plant hormone signal transduction, response to chitin, response to carbohydrates, response to wounding in starch and sucrose metabolism, phenylpropionic acid biosynthesis, and flavonoid biosynthesis. Nine candidate DEGs were verified using real-time quantitative reverse transcription PCR. These results suggest that GmERF071 plays a key role in SCN resistance and could be used in genomics-assisted breeding to develop soybean varieties with increased resistance to SCN.

Bisphenol AF induces cell cycle arrest and apoptosis in TM3 Leydig cells via the p53 signaling pathway

Bisphenol AF (BPAF), one of the most common bisphenol analogues, has been reported to exhibit higher estrogenic activity compared to bisphenol A (BPA) due to the presence of additional hydrophobic groups. To comprehensively understand the male reproductive toxicity of BPAF, TM3 Leydig cells were used to investigate the effects of BPAF on cell proliferation, apoptosis, and cell cycle arrest. The underlying mechanisms of cellular responses induced by BPAF were examined through analysis of target mRNA and protein expression. Results showed that BPAF treatment reduced cell viability and induced both G2/M cell cycle arrest and apoptosis in a time- and dose-dependent manner in TM3 Leydig cells. RNA sequencing analysis and experimental verification further revealed that the p53 signaling pathway was involved in BPAF-induced cytotoxicity. Furthermore, Pifithrin-α (PFT-α), a p53 inhibitor, attenuated BPAF-induced G2/M cell cycle arrest and apoptosis. These results demonstrate that the p53 signaling pathway mediates BPAF-induced cell cycle arrest and apoptosis in Leydig cells, providing mechanistic insights into BPAF's toxicological effects on the male reproductive system.

Comparative Transcriptome Analysis of Gene Responses of Salt-Tolerant and Salt-Sensitive Watermelon Cultivars' Roots to Salt Stress

Salt stress, as a significant adverse consequence of global climate change, severely restricts the yield and quality of watermelon. In this study, salt-tolerant cultivar T23 and salt-sensitive cultivar B2 were subjected to a 200 mM NaCl treatment (0 h, 6 h, 24 h, 48 h, and 168 h) at the three-leaf stage, and the adaptation mechanisms of the watermelon roots to salt stress were systematically investigated at the phenotypic, physiological, and gene transcription levels. Phenotypic observations revealed that salt stress inhibited seedling growth, caused leaf curling, and induced root yellowing, with the damage being significantly more severe in B2 than in T23. Compared with B2, the activities of superoxide dismutase (SOD) were increased by -7.13%, 169.15%, 34.95%, 84.87%, and 39.87% under NaCl treatment at 0 h, 6 h, 24 h, 48 h, and 168 h, respectively. Compared to the 0 h NaCl treatment, the proline content in B2 increased by 4.25%, 14.39%, and 110.00% at 24 h, 48 h, and 168 h of NaCl treatment, respectively, while T23 showed increases of 93.74%, 177.55%, and 380.56% at the corresponding time points. The provided physiological data demonstrate that T23 exhibits superior antioxidant and osmoregulatory abilities relative to B2. The transcriptome analysis identified differentially expressed genes (DEGs) between the two cultivars under salt stress, with T23 showing the highest number of DEGs at 6 h, while B2 exhibited a significant increase in DEGs at 168 h. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that metabolic pathways such as plant hormone signal transduction, terpenoid biosynthesis, mitogen-activated protein kinase (MAPK) signaling pathways, transporter activity, and transcription regulator activity play important roles in the salt stress response. Furthermore, yeast overexpression experiments preliminarily validated the critical roles of the tonoplast dicarboxylate transporter gene ClCG01G010280 and the NAC transcription factor gene ClCG05G024110 in salt stress tolerance. This study provides new molecular insights into the salt tolerance mechanism of watermelon and offers potential genetic resources for breeding salt-tolerant varieties.

Combined transcriptomic and metabolomic analysis revealed the salt tolerance mechanism of Populus talassica × Populus euphratica

BACKGROUND

To investigate the salt tolerance of Populus talassica × Populus euphratica, morphological and physiological parameters were measured on the second day after the 15th, 30th and 45th days of NaCl treatment, revealing significant effects of NaCl on growth. To further elucidate the mechanisms underlying salt tolerance, transcriptomic and metabolomic analysis were conducted under different NaCl treatments.

RESULTS

The results of morphological and physiological indexes showed that under low salt treatment, P. talassica × P. euphratica was able to coordinate the growth of aboveground and belowground parts. Under high salt concentration, the growth and water balance of P. talassica × P. euphratica were markedly inhibited. The most significant differences between treatments were observed on the second day after the 45th day of NaCl treatment. Transcriptomic analysis showed that the pathways of gene enrichment in the roots and stems of P. talassica × P. euphratica were different in the salt resistance response. And it involves several core pathways such as plant hormone signal transduction, phenylpropanoid biosynthesis, MAPK signaling pathway-plant, plant- pathogen interaction, carbon metabolism, biosynthesis of amino acids, and several key Transcription factors (TFs) such as AP2/ERF, NAC, WRKY and bZIP. Metabolomic analysis revealed that KEGG pathway enrichment analysis showed unique metabolic pathways were enriched in P. talassica × P. euphratica under both 200 mM and 400 mM NaCl treatments. Additionally, while there were some differences in the metabolic pathways enriched in the roots and stems, both tissues commonly enriched pathways related to the biosynthesis of secondary metabolites, biosynthesis of cofactors, biosynthesis of amino acids, flavonoid biosynthesis, and ABC transporters. Association analysis further indicated that biosynthesis of amino acids and plant hormone signal transduction pathway play key roles in the response of P. talassica × P. euphratica to salt stress. The interactions between the differentially expressed genes (DEGs) and several differentially accumulated metabolites (DAMs), especially the strong association between LOC105124002 and Jasmonoyl-L-Isoleucine (pme2074), were again revealed by the interactions analysis.

CONCLUSIONS

In this study, we resolved the changes of metabolic pathways in roots and stems of P. talassica × P. euphratica under different NaCl treatments and explored the associations between characteristic DEGs and DAMs, which provided insights into the mechanisms of P. talassica × P. euphratica in response to salt stress.

Insights into the synergistic effects of exogenous glycine betaine on the multiphase metabolism of oxyfluorfen in Oryza sativa for reducing environmental risks

Glycine betaine (GB), a secondary metabolite that regulates plant responses to biotic and abiotic stresses, may help reduce pesticide phytotoxicity, but this fact remains unestablished. This study investigated the physiological response of rice (Oryza sativa) to six dosages of oxyfluorfen (OFF) (0-0.25 mg/L) and two concentrations of GB (0 and 175 mg/L). GB treatment counteracted the considerable decrease in rice seedling growth caused by OFF treatment at doses higher than 0.15 mg/L. The biochemical processes and catalytic events associated with OFF-triggered degradation in rice were investigated using RNA-Seq-LC-Q-TOF-HRMS/MS after six rice root and shoot libraries were created and subjected to either OFF or OFF-GB. Rice treated with both GB and an ecologically relevant dose of OFF showed a marked upregulation of 1039 root genes and 111 shoot genes compared with those treated with OFF alone. Multiple OFF-degradative enzymes implicated in molecular metabolism and xenobiotic tolerance to environmental stress were identified by gene enrichment analysis. In comparison to treated with 0.25 mg/L OFF alone, exogenous GB administration decreased OFF accumulation, with the OFF concentration in roots being 44.47 % and in shoots being 51.03 %. The production of essential enzymes involved in the OFF decay process was attributed to certain genes with variable expression, including cytochrome P450, methyltransferase, glycosyltransferases, and acetyltransferases. Using LC-Q-TOF-HRMS/MS, 3 metabolites and 16 conjugates were identified in metabolic pathways including hydrolysis, acetylation, glycosylation, and interaction with amino acids in order to enhance OFF-degradative metabolism. All things considered, by reducing phytotoxicity and OFF buildup, external GB treatment can increase rice's resistance to oxidative stress caused by OFF. This study offers valuable insights into the function of GB in enhancing OFF degradation, which may have ramifications for designing genotypes that maximize OFF accumulation in rice crops and promote OFF degradation in paddy crops.

Comparative phenotypic, physiological, and transcriptomic responses to drought and recovery in two Fraxinus species

BACKGROUND

This study focused on the drought tolerance and resilience of two ash species: Fraxinus chiisanensis and F. rhynchophylla. These two species are distributed in different habitats, suggesting that they have different levels of drought tolerance. Understanding their response to drought stress, particularly during the seedling stage, is crucial for selecting and developing drought-resistant varieties. This study aimed to compare the phenotypic, physiological, and transcriptomic characteristics of drought-stressed and recovered rewatered plants in a time-course experiment.

RESULTS

In F. rhynchophylla, drought stress resulted in more severe growth retardation, temperature increase, and a faster decline in the fluorescence response, accompanied by a significant rise in stress indices. However, these reactions recovered quickly after rehydration. In contrast, F. chiisanensis exhibited less growth retardation, a slower decline in fluorescence, and milder increases in stress indices, although many individuals did not fully recover after rehydration. The activity of antioxidant enzymes (SOD, CAT, APX) was more responsive and recovered more efficiently in F. rhynchophylla, while F. chiisanensis had a weaker and delayed response. Transcriptome analysis revealed that photosynthesis and enzyme activity were the most responsive to drought and recovery, as shown by Gene Ontology term analysis. Kyoto Encyclopedia of Genes and Genomes pathway analysis identified common pathways involved in starch and sucrose metabolism and phenylpropanoid biosynthesis in both species. F. rhynchophylla had more differentially expressed genes (DEGs) than F. chiisanensis, particularly on the drought and recovery day 6. Most drought-induced DEGs were restored after rehydration. Commonly associated genes included BGLU and TPS in sugar metabolism; CAT, GSTF, TT7, and HCT in antioxidant enzymes; PYL4 and RR17 in hormone signaling; and ADC1 and ASP3 in proline synthesis.

CONCLUSIONS

This study highlights the species-specific characteristics of drought and recovery responses of two Fraxinus species and provides targets for assessing and improving drought tolerance. Moreover, the results of this study provide insights into the physiological and genetic responses of Fraxinus and may guide future research on ash tree stress tolerance.

Analysis of salinity-induced metabolome changes in Indian mustard (Brassica juncea) roots and shoots: hydroponic versus microplot cultivation

BACKGROUND

Brassica juncea L. (family Brassicaceae) or Indian mustard is a fast-growing oilseed crop. Climate changes mean that it is very important to evaluate the effects of salinity stress on B. juncea. The aim of this study was therefore to show the metabolic effect of salinity stress on shoots and roots using two cultivation models - hydroponic and microplot - in different cultivars, including RH-725 and RH-761. Salinity levels of 5, 7.5, and 10 dS m⁻¹ were investigated, and compared with a control of 0 dS m⁻¹, using untargeted metabolomics with gas chromatography-mass spectrometry (GC-MS) post-silylation, focusing on metabolic markers such as proline and glycine-betaine.

RESULTS

A total of 56 metabolites were identified, with the most prevalent classes belonging to sugars (8), followed by organic acids (13), amino acids (11), and fatty acids/esters (11). Shoots were found to have a higher sugar content than roots. Increases in unsaturated fatty acids were also associated with salinity stress, compared with a decrease in saturated fatty acids. Absolute levels of proline and glycine-betaine correlated with salinity stress, with the largest increases detected in shoots grown under hydroponic conditions, particularly for the RH-761 cultivar. Multivariate data analyses revealed that roots were more affected than shoots, regardless of cultivation model.

CONCLUSION

These findings might explain the different metabolic behavior of B. juncea's roots and shoots under various levels of salinity, associated with higher levels of free sugars in shoots and lipids in roots. © 2024 Society of Chemical Industry.

Fermentative profile and bacterial community structure of whole-plant triticale silage (Triticosecale Wittmack) with or without the addition of Streptococcus bovis and Lactiplantibacillus plantarum

This study aimed to investigate the effects of Streptococcus bovis and Lactiplantibacillus plantarum on the chemical composition, fermentation characteristics, bacterial communities, and predicted metabolic pathways of whole-plant triticale silage (Triticosecale Wittmack). Fresh triticale harvested at the milk stage was ensiled in sterile distilled water (CON), Streptococcus bovis (ST), Lactiplantibacillus plantarum (LP), and a combination of S. bovis and L. plantarum (LS) for 3, 7, 15, and 30 days. During ensiling, the pH and water-soluble carbohydrate (WSC) content in the inoculated groups was significantly lower than those in the CON group (P < 0.05), especially in the LS group (P < 0.05). After 7 days of ensiling, the ST and LS groups had lower (P < 0.05) starch content and higher (P < 0.05) concentrations of lactic acid (LA) and acetic acid (AA). Inoculation with S. bovis and L. plantarum, either alone or in combination, increased the abundance of Lactobacillus and Pediococcus while reducing the abundance of Weissella, Rosenbergiella, Pantoea, and Enterobacter. Metabolic prediction analysis indicated that inoculation with S. bovis enhanced starch and sucrose metabolism during the early stages of ensiling. The abundance of Streptococcus positively correlated with LA (P < 0.05) and AA concentration but negatively correlated with starch content, pH, and propionic acid (PA) concentration (P < 0.05). S. bovis inoculation increased starch hydrolysis and carbohydrate metabolism during the early stages. S. bovis and L. plantarum synergistically improved the fermentation characteristics and bacterial communities of triticale silage. Therefore, S. bovis can be used as an additive or for a fast start-up agent to improve silage fermentation quality.IMPORTANCEEnsiling is a widely used method for preserving fresh forage. Silage quality is determined by the chemical and microbial composition. Studies have shown that S. bovis grew faster than commercial species, thereby creating advantages for other lactic acid bacteria during ensiling. Therefore, we believe that S. bovis and L. plantarum can synergistically improve the fermentation characteristics and bacterial community in silage. However, few studies use high-throughput methods to explain the impact of S. bovis on silage fermentation. Results showed that S. bovis significantly affected the fermentation parameters, bacterial community, and metabolic characteristics of triticale silage. S. bovis and L. plantarum synergistically accelerated the fermentation, reducing pH and WSC while increasing lactic acid and acetic acid concentrations in the early stages of ensiling. Additionally, co-inoculation increased the abundance of Lactobacillus and Pediococcus and carbohydrate metabolism. This study emphasizes the synergistic role of S. bovis and L. plantarum in enhancing triticale silage quality, providing scientific support for novel silage additives.

Transcriptomic and metabolomic analyses reveal the positive effect of moderate concentration of sodium chloride treatment on the production of β-carotene, torulene, and torularhodin in oleaginous red yeast Rhodosporidiobolus odoratus XQR

Carotenoids, a family of lipid-soluble pigments, have garnered growing interest for their health-promoting benefits and are widely utilized in the food, feed, pharmaceutical, and cosmetic industries. Rhodosporidiobolus odoratus, a representative oleaginous red yeast, is considered a promising alternative for producing high-value carotenoids including β-carotene, torulene, and torularhodin. Here, the impact of varying concentrations of NaCl treatments on carotenoid contents in R. odoratus XQR after 120 h of incubation was examined. The results indicated that, as compared to the control (59.37 μg/gdw), the synthesis of total carotenoids was significantly increased and entirely suppressed under low-to-moderate (0.25 mol/L: 68.06 μg/gdw, 0.5 mol/L: 67.62 μg/gdw, and 0.75 mol/L: 146.47 μg/gdw) and high (1.0, 1.25, and 1.5 mol/L: 0 μg/gdw) concentrations of NaCl treatments, respectively. Moreover, the maximum production of β-carotene (117.62 μg/gdw), torulene (21.81 μg/gdw), and torularhodin (7.04 μg/gdw) was achieved with a moderate concentration (0.75 mol/L) of NaCl treatment. Transcriptomic and metabolomic analyses suggested that the increase in β-carotene, torulene, and torularhodin production might be primarily attributed to the up-regulation of some key protein-coding genes involved in the terpenoid backbone biosynthesis (atoB, HMGCS, and mvaD), carotenoid biosynthesis (crtYB and crtI), and TCA cycle (pckA, DLAT, pyc, MDH1, gltA, acnA, IDH1/2, IDH3, sucA, sucB, sucD, LSC1, SDHA, and fumA/fumB). The present study not only demonstrates a viable method to concurrently increase the production of β-carotene, torulene, torularhodin, and total carotenoids in R. odoratus XQR, but it also establishes a molecular foundation for further enhancing their production through genetic engineering.

Comparative Transcriptome Analysis Reveals Mechanisms of Differential Salinity Tolerance Between Suaeda glauca and Suaeda salsa

BACKGROUND

Suaeda glauca and Suaeda salsa have obvious morphological features and strongly tolerate saline-alkali environments. However, the mechanisms that lead to the differences in saline-alkali tolerance between them remain unclear.

METHODS

In this study, we employed comparative transcriptome analysis to investigate S. glauca and S. salsa under saline-alkali stress.

RESULTS

Our sequencing efforts resulted in the identification of 99,868 unigenes. We obtained 12,021 and 6227 differentially expressed genes (DEGs) from the S. glauca and S. salsa under salt stress compared with plants in the control. Notably, 1189 and 1864 were specifically upregulated DEGs in the roots and leaves of S. salsa under saline-alkali conditions, respectively. These genes were enriched in pathways such as "Plant hormone signal transduction", "Carbon metabolism" and "Starch and sucrose metabolism". Further analysis of stress-related pathways and gene expression levels revealed that key genes involved in abscisic acid (ABA) and jasmonic acid (JA) biosynthesis, ABA signal transduction, and their downstream transcription factors were upregulated in the roots of S. salsa under saline-alkali conditions. Additionally, 24 DEGs associated with stress response were identified in the roots and leaves of both species. The expression levels of these pathways and related genes were higher in S. salsa than in S. glauca, suggesting that S. salsa enhances its saline-alkali tolerance by elevating the expression of these genes.

CONCLUSIONS

This study provides a new research perspective for revealing the differences in saline-alkali tolerance mechanisms between S. glauca and S. salsa, bringing forth important candidate genes for studying their saline-alkali tolerance.

Exogenous silicon improved the cell wall stability by activating non-structural carbohydrates and structural carbohydrates metabolism in salt and drought stressed Glycyrrhiza uralensis stem

The plant cell wall is a crucial barrier against environmental stress, mainly composed of lignin and carbohydrates such as cellulose, hemicellulose, and pectin. This study explored the direct regulatory mechanism of silicon (Si) on cell wall components of Glycyrrhiza uralensis (G. uralensis) stems under salt and drought (S + D) stress and the indirect regulatory mechanism of non-structural carbohydrates on structural carbohydrates, mediated by uridine diphosphate glucose (UDPG), through joint physiological, biochemical, and transcriptomic analyses. Under S + D stress, Si increased the contents of cell wall components, altered the structure of cell wall, and directly promoted cell wall re-construction by regulating gene expression levels and enzyme activities related to cell wall biosynthesis. Meanwhile, Si facilitated the accumulation of carbohydrates by regulating enzyme activities and gene expression levels in the anabolic pathway of polysaccharides, thereby promoting UDPG conversion and indirectly providing substrates for cell wall synthesis. In conclusion, Si directly and indirectly facilitates the synthesis of cell wall components by regulating both cell wall metabolism and non-structural carbohydrates metabolism, thus reinforcing the cell wall, enhancing its stability, and improving the salt and drought tolerance of G. uralensis stems.

Chloride accumulation in inland rivers of China and its toxic impact on cotton

The escalation of major ion concentrations in freshwater and soil poses diverse effects on ecosystems and the environment. Excessive ions can exhibit toxicity to aquatic organisms and terrestrial plants. Currently, research on ion toxicity primarily focuses on cation toxicity. Notably, there is a noticeable research gap in understanding the impact of chloride ion (Cl-) on plant growth and development, as well as on the defense mechanisms against Cl- toxicity. In the present study, sampling was conducted on major rivers in China to measure Cl- concentrations. The results revealed that certain rivers exhibited excessive levels of Cl-, emphasizing the critical need to address Cl- toxicity issues. Subsequently, when salt-tolerant cotton seedlings were subjected to various chloride treatments, it was observed that excessive Cl- severely hindered plant growth and development. A combined analysis of transcriptomic and metabolomic data shed light on significantly enriched pathways related to galactose metabolism, arginine and proline metabolism, carotenoid metabolism, and alpha-linolenic acid metabolism under chloride stress. In summary, this research provides a scientific foundation and references for environmental management and water resource protection and offers novel insights for mitigating the adverse impacts of Cl-, thereby contributing to the preservation of ecosystem health.

Acyl hydrazone derivatives with trifluoromethylpyridine as potential agrochemical for controlling plant diseases

BACKGROUND

Crops are consistently under siege by a multitude of pathogens. These pathogenic microorganisms, including viruses and bacteria, result in substantial reductions in quality and yield globally by inducing detrimental crop diseases, thus posing a significant challenge to global food security. However, the biological activity sepectrum of commercially available pesticides is limited and the pesticide efficacy is poor, necessitating the urgent development of broad-spectrum and efficient strategies for crop disease prevention and control.

RESULTS

The bioassay results revealed that certain target compounds demonstrated outstanding in vivo antiviral efficacy against cucumber mosaic virus and tobacco mosaic virus. In particular, compound D6 showed remarkable antiviral activity against CMV, significantly higher than that of the control agent ningnanmycin. Mechanism of action studies have shown that compound D6 could enhance the activity of defense enzymes and upregulate the expression of genes related to disease resistance, thereby enhancing the antiviral effects in plants. In addition, these compounds displayed superior inhibitory activity against plant bacterial diseases. For Xoo, compound D10 showed an excellent inhibitory effect that was better than that of the control agent bismerthiazol. Scanning electron microscopy and fluorescence double-staining experiments revealed that compound D10 effectively inhibited bacterial growth by disrupting the cell membrane.

CONCLUSION

A series of trifluoromethyl hydrazone derivatives were designed and synthesized, and it was found that they have control effects on plant viruses and bacterial diseases. In addition, this study revealed the mechanism of action of the active compounds and demonstrated their potential as multifunctional crop protectants. © 2024 Society of Chemical Industry.

Widely Targeted Metabolomics Analysis Revealed the Component Differences of Hemerocallis citrina Borani in Different Production Areas of Datong

Hemerocallis citrina Borani (H. citrina) has garnered significant attention due to its abundant nutritional quality. Datong, located in Shanxi Province, is recognized as one of the four major production regions for high-quality H. citrina. While Datong boasts multiple production areas, the nutritional composition of daylilies varies across regions due to environmental factors and planting patterns, which remain unclear. This study focuses on the total polyphenol and flavonoid contents (TPCs and TFCs) and protein content of H. citrina from three areas in Datong: Sanshilipu (DTSSLP), Dangliuzhuang (DTDLZ), and Jijiazhuang (DTJJZ). Additionally, a widely targeted metabolomics analysis was used to analyze the metabolite composition of H. citrina from these three areas. The results showed that H. citrina in DTSSLP had the highest contents of protein and amino acids, as well as TPCs and TFCs. A total of 798 differential metabolites were identified in H. citrina across the areas, with DTSSLP showing the highest levels of different classifications of metabolites, indicating its enhanced health benefits and physiological activities. Nine metabolic pathways were related with the different characteristics among DTSSLP, DTDLZ, and DTJJZ. This study provides theoretical support for distinguish H. citrina from different producing regions and elucidates the mechanisms underlying its metabolic pathways.

Streptomyces improves sugarcane drought tolerance by enhancing phenylalanine biosynthesis and optimizing the rhizosphere environment

Drought stress is a common hazard faced by sugarcane growth, and utilizing microorganisms to enhance plant tolerance to abiotic stress has become an important method for sustainable agricultural development. Several studies have demonstrated that Streptomyces chartreuses WZS021 improves sugarcane tolerance to drought stress. However, the molecular mechanisms underlying tolerance at the transcriptional and metabolomic levels remain unclear. We comprehensively evaluated the physiological and molecular mechanisms by which WZS021 enhances drought tolerance in sugarcane, by performing transcriptome sequencing and non-targeted metabolomics; and examining rhizosphere soil properties and plant tissue antioxidant capacity. WZS021 inoculation improved the rhizosphere nutritional environment (AP, ammonia, OM) of sugarcane and enhanced the antioxidant capacity of plant roots, stems, and leaves (POD, SOD, CAT). Comprehensive analyses of the transcriptome and metabolome revealed that WZS021 mainly affects plant drought tolerance through phenylalanine metabolism, plant hormone signal transduction, and flavonoid biosynthesis pathways. The drought tolerance signaling molecules mediated by WZS021 include petunidin, salicylic acid, α-Linoleic acid, auxin, geranylgeraniol and phenylalanine, as well as key genes related to plant hormone signaling transduction (YUCCA, amiE, AUX, CYPs, PAL, etc.). Interestingly, inoculation with WZS021 during regular watering induces a transcriptome-level response to biological stress in sugarcane plants. This study further elucidates a WZS021-dependent rhizosphere-mediated regulatory mechanism for improving sugarcane drought tolerance, providing a theoretical basis for increasing sugarcane production capacity.

Ecophysiological, transcriptomic and metabolomic analyses shed light on the response mechanism of Bruguiera gymnorhiza to upwelling stress

Mangroves, due to their unique habitats, endure dual stressors from land to ocean and ocean to land directions. While extensive researches have been conducted on land-ocean stressors, studies on ocean-land stressors like upwelling are considerably scarce. In this study, ecophysiological, transcriptome, and metabolome analyses were conducted to determine the responses of mangrove plant (Bruguiera gymnorhiza, B. gymnorhiza) to upwelling stress. The results suggested that upwelling stress in B. gymnorhiza induces oxidative stress and membrane damage, which are mitigated by the synergistic actions of antioxidant enzymes and osmoprotectants. Transcriptomic and metabolomic analyses revealed that upregulated genes related to oxidation-reduction and carbohydrate metabolism, along with accumulated metabolites such as amino acids, lipids, phenols, and organic acids, contribute to enhancing antioxidant capacity and maintaining osmotic balance. Further analysis identified key KEGG pathways involved in the response to upwelling stress, including amino acid metabolism, carbohydrate and energy metabolism, flavonoid biosynthesis, and plant hormone signal transduction. These findings provide vital information into the multi-level response mechanisms of mangrove plants to upwelling stress.

The influence of environment on invasive Carpobrotus sp. populations across genetic clusters

The study aims to explore the natural variation in the metabolome of different populations of the invasive plant Carpobrotus from different genetic clusters and geographical origins to enhance our comprehension of its involvement in the adaptation process and phenotypic diversity. The metabolomic profile of shoots was analysed in four populations from two different genetic clusters (Cluster A: Cádiz and A Lanzada; Cluster B: La Marina and Samil) and two different biogeographical regions in Spain (Atlantic: Samil and A Lanzada; Mediterranean: Cádiz and La Marina), collected in the field and subsequently grown in the greenhouse. In addition, climatic, and physiological parameters were analysed. The Mediterranean populations (Cádiz and La Marina) showed lower initial weight and length measurements in morphological parameters than the Atlantic populations. On the contrary, only root parameters showed significant differences in growth parameters among populations. The analysis of ion levels revealed a consistent pattern of higher concentrations in shoots compared to roots, with significant differences among populations, particularly in sodium (Na+) and chlorides (Cl-) levels. Regarding metabolomic analysis, clear correlations between the metabolome, genetic and climatic conditions of Carpobrotus sp.pl populations are described. Pairwise comparisons using t-tests and Principal Component Analysis (PCA) indicated that the differences in metabolomic profile between the Samil and La Marina populations, which correspond to the same genetic cluster (cluster B), were smaller than in the rest of the comparisons indicating that populations from the same genetic cluster were more similar metabolically than those from the same climatic region. The study identified key metabolites representative of each cluster, with significant differences in amino acids, organic acids, and sugars contributing to the variation among populations. Pathway analysis highlighted the impact of climatic conditions on metabolic pathways, particularly in populations from Cluster A. In conclusion, the different populations were more similar according to the genetic cluster than to the climatic region of origin when studied at the metabolomic level. Consequently, the metabolites more representative of each cluster were also identified.

A Genome-Wide Analysis of the BAM Gene Family and Identification of the Cold-Responsive Genes in Pomegranate (Punica granatum L.)

Beta-amylases (BAMs, EC 3.2.1.2), belonging to a multigene family, play a pivotal role in starch breakdown and are also involved in hormonal and stress responses, notably to cold stress. Pomegranate trees (Punica granatum L.) are adapted to warm climates and are sensitive to cold temperatures. In this study, we analyzed eight PgBAM genes from the pomegranate genome dataset. These members unevenly distributed across chromosomes and were categorized into four groups based on their orthologous members. The motif composition was highly consistent among most members. In contrast, exon numbers and arrangements were conserved within groups or subgroups, whereas significant diversity was observed between different groups. A syntenic analysis revealed that three PgBAM members (PgBAM1/4/5) showed a total of 11 syntenic relationships with the BAM members from Arabidopsis, kiwifruit, and Chinese white pear, respectively. Promoter binding motif prediction suggested potential roles for PgBAMs' genes in light, stress, hormones, and development signaling. Gene expression indicated that PgBAM4 was predominantly expressed in leaves, PgBAM7 in flowers, and PgBAM8 in roots and leaves and during fruit ripening, particularly in pericarp development. A transcriptome analysis identified the starch and sucrose metabolism pathway (map00500) as a key factor in the cold stress response of cold-sensitive cultivar 'Tunisia' seedlings. PgBAM4 exhibited remarkable expression and was closely associated with the cold-responsive BAM genes, characterized by a closer phylogenetic relationship, conserved catalytic residues, and similar secondary and tertiary structures. Moreover, the differences in soluble sugar levels and PgBAM4 expression were closely associated with the varying cold stress resistance observed between 'Tunisia' and 'Sanbai' seedlings. Furthermore, yeast one-hybrid assays confirmed that PgCBF7, a critical transcription factor for enhancing freezing tolerance, binds to the promoter region of PgBAM4. Our findings provide a systematic overview of the PgBAM gene family and shed new light on the regulatory mechanisms underlying cold stress tolerance in pomegranate.

Acetylation proteomics and metabolomics analyses reveal the involvement of starch synthase undergoing acetylation modification during UV-B stress resistance in Rhododendron Chrysanthum Pall

BACKGROUND

Rhododendron chrysanthum Pall. (R. chrysanthum) is a plant that lives in high mountain with strong UV-B radiation, so R. chrysanthum possess resistance to UV-B radiation. The process of stress resistance in plants is closely related to metabolism. Lysine acetylation is an important post-translational modification, and this modification process is involved in a variety of biological processes, and affected the expression of enzymes in metabolic processes. However, little is known about acetylation proteomics during UV-B stress resistance in R. chrysanthum.

RESULTS

In this study, R. chrysanthum OJIP curves indicated that UV-B stress damaged the receptor side of the PSII reaction center, with a decrease in photosynthesis, a decrease in sucrose content and an increase in starch content. A total of 807 differentially expressed proteins, 685 differentially acetylated proteins and 945 acetylation sites were identified by quantitative proteomic and acetylation modification histological analysis. According to COG and subcellular location analyses, DEPs with post-translational modification of proteins and carbohydrate metabolism had important roles in resistance to UV-B stress and DEPs were concentrated in chloroplasts. KEGG analyses showed that DEPs were enriched in starch and sucrose metabolic pathways. Analysis of acetylation modification histology showed that the enzymes in the starch and sucrose metabolic pathways underwent acetylation modification and the modification levels were up-regulated. Further analysis showed that only GBSS and SSGBSS changed to DEPs after undergoing acetylation modification. Metabolomics analyses showed that the metabolite content of starch and sucrose metabolism in R. chrysanthum under UV-B stress.

CONCLUSIONS

Decreased photosynthesis in R. chrysanthum under UV-B stress, which in turn affects starch and sucrose metabolism. In starch synthesis, GBSS undergoes acetylation modification and the level is upregulated, promotes starch synthesis, making R. chrysanthum resistant to UV-B stress.

Comparative transcriptome revealed the molecular responses of Aconitum carmichaelii Debx. to downy mildew at different stages of disease development

BACKGROUND

Aconitum carmichaelii Debx. has been widely used as a traditional medicinal herb for a long history in China. It is highly susceptible to various dangerous diseases during the cultivation process. Downy mildew is the most serious leaf disease of A. carmichaelii, affecting plant growth and ultimately leading to a reduction in yield. To better understand the response mechanism of A. carmichaelii leaves subjected to downy mildew, the contents of endogenous plant hormones as well as transcriptome sequencing were analyzed at five different infected stages.

RESULTS

The content of 3-indoleacetic acid, abscisic acid, salicylic acid and jasmonic acid has changed significantly in A. carmichaelii leaves with the development of downy mildew, and related synthetic genes such as 9-cis-epoxycarotenoid dioxygenase and phenylalanine ammonia lyase were also significant for disease responses. The transcriptomic data indicated that the differentially expressed genes were primarily associated with plant hormone signal transduction, plant-pathogen interaction, the mitogen-activated protein kinase signaling pathway in plants, and phenylpropanoid biosynthesis. Many of these genes also showed potential functions for resisting downy mildew. Through weighted gene co-expression network analysis, the hub genes and genes that have high connectivity to them were identified, which could participate in plant immune responses.

CONCLUSIONS

In this study, we elucidated the response and potential genes of A. carmichaelii to downy mildew, and observed the changes of endogenous hormones content at different infection stages, so as to contribute to the further screening and identification of genes involved in the defense of downy mildew.

Genome-Wide Identification and Expression Analysis of the Starch Synthase Gene Family in Sweet Potato and Two of Its Closely Related Species

The starch synthase (SS) plays important roles in regulating plant growth and development and responding to adversity stresses. Although the SS family has been studied in many crops, it has not been fully identified in sweet potato and its two related species. In the present study, eight SSs were identified from Ipomoea batatas (I. batata), Ipomoea trifida (I. trifida), and Ipomoea trlioba (I. trlioba), respectively. According to the phylogenetic relationships, they were divided into five subgroups. The protein properties, chromosomal location, phylogenetic relationships, gene structure, cis-elements in the promoter, and interaction network of these proteins were also analyzed; stress expression patterns were systematically analyzed; and real-time polymerase chain reaction (qRT-PCR) analysis was performed. Ipomoea batatas starch synthase (IbSSs) were highly expressed in tuber roots, especially Ipomoea batatas starch synthase 1 (IbSS1) and Ipomoea batatas starch synthase 6 (IbSS6), which may play an important role in root development and starch biosynthesis. At the same time, the SS genes respond to potassium deficiency, hormones, cold, heat, salt, and drought stress. This study offers fresh perspectives for enhancing knowledge about the roles of SSs and potential genes to enhance productivity, starch levels, and resistance to environmental stresses in sweet potatoes.

An evaluation of Astragali Radix with different growth patterns and years, based on a new multidimensional comparison method

Introduction

With the depletion of wild Astragali Radix (WA) resources, imitated-wild Astragali Radix (IWA) and cultivated Astragali Radix (CA) have become the main products of Astragali Radix. However, the quality differences of three growth patterns (WA, IWA, CA) and different growth years of Astragali Radix have not been fully characterized, leading to a lack of necessary scientific evidence for their use as substitutes for WA.

Methods

We innovatively proposed a multidimensional evaluation method that encompassed traits, microstructure, cell wall components, saccharides, and pharmacodynamic compounds, to comprehensively explain the quality variances among different growth patterns and years of Astragali Radix.

Results and discussion

Our study showed that the quality of IWA and WA was comparatively similar, including evaluation indicators such as apparent color, sectional structure and odor, thickness of phellem, diameter and number of vessels, morphology of phloem and xylem, and the levels and ratios of cellulose, hemicellulose, lignin, sucrose, starch, water-soluble polysaccharides, total-saponins. However, the content of sucrose, starch and sorbose in CA was significantly higher than WA, and the diameter and number of vessels, total-flavonoids content were lower than WA, indicating significant quality differences between CA and WA. Hence, we suggest that IWA should be used as a substitute for WA instead of CA. As for the planting years of IWA, our results indicated that IWA aged 1-32 years could be divided into three stages according to their quality change: rapid growth period (1-5 years), stable growth period (6-20 years), and elderly growth period (25-32 years). Among these, 6-20 years old IWA exhibited consistent multidimensional comparative results, showcasing elevated levels of key active components such as water-soluble polysaccharides, flavonoids, and saponins. Considering both the quality and cultivation expenses of IWA, we recommend a cultivation duration of 6-8 years for growers. In conclusion, we established a novel multidimensional evaluation method to systematically characterize the quality of Astragali Radix, and provided a new scientific perspective for the artificial cultivation and quality assurance of Astragali Radix.

Discrepancy of Growth Toxicity of Polystyrene Nanoplastics on Soybean (Glycine max) and Mung Bean (Vigna radiata)

Nanoplastics, as a hot topic of novel contaminants, lack extensive concern in higher plants; especially the potential impact and mechanism of nanoplastics on legume crops remains elusive. In this study, the toxicity of polystyrene nanoplastics (PS-NPs, 200 nm) with diverse doses (control, 10, 50, 100, 200, 500 mg/L) to soybean and mung bean plants grown hydroponically for 7 d was investigated at both the macroscopic and molecular levels. The results demonstrated that the root length of both plants was markedly suppressed to varying degrees. Similarly, mineral elements (Fe, Zn) were notably decreased in soybean roots, consistent with Cu alteration in mung bean. Moreover, PS-NPs considerably elevated malondialdehyde (MDA) levels only in soybean roots. Enzyme activity data indicated mung bean exhibited significant damage only at higher doses of PS-NPs stress than soybean, implying mung bean is more resilient. Transcriptome analysis showed that PS-NPs stimulated the expression of genes associated with the antioxidant system in plant roots. Furthermore, starch and sucrose metabolism might play a key role in coping with PS-NPs to enhance soybean resistance, but the MAPK pathway was enriched in mung bean. Our findings provide valuable perspectives for an in-depth understanding of the performance of plants growing in waters contaminated by nanoplastics.

Time-Course Transcriptome Analysis of Aquilegia vulgaris Root Reveals the Cell Wall's Roles in Salinity Tolerance

Salt stress has a considerable impact on the development and growth of plants. The soil is currently affected by salinisation, a problem that is becoming worse every year. This means that a significant amount of salt-tolerant plant material needs to be added. Aquilegia vulgaris has aesthetically pleasing leaves, unique flowers, and a remarkable tolerance to salt. In this study, RNA-seq technology was used to sequence and analyse the transcriptome of the root of Aquilegia vulgaris seedlings subjected to 200 mM NaCl treatment for 12, 24, and 48 h. In total, 12 Aquilegia vulgaris seedling root transcriptome libraries were constructed. At the three time points of salt treatment compared with the control, 3888, 1907, and 1479 differentially expressed genes (DEGs) were identified, respectively. Various families of transcription factors (TFs), mainly AP2, MYB, and bHLH, were identified and might be linked to salt tolerance. Gene Ontology (GO) analysis of DEGs revealed that the structure and composition of the cell wall and cytoskeleton may be crucial in the response to salt stress. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of the DEGs showed a significant enrichment of the pentose and glucuronate interconversion pathway, which is associated with cell wall metabolism after 24 and 48 h of salt treatment. Based on GO and KEGG analyses of DEGs, the pentose and glucuronate interconversion pathway was selected for further investigation. AP2, MYB, and bHLH were found to be correlated with the functional genes in this pathway based on a correlation network. This study provides the groundwork for understanding the key pathways and gene networks in response to salt stress, thereby providing a theoretical basis for improving salt tolerance in Aquilegia vulgaris.

Transcriptome analyses reveal photosynthesis-related genes involved in photosynthetic regulation under low temperature stress in Lavandula angustifolia Mill

In order to reveal the mechanisms of photosynthetic regulation of Lavandula angustifolia Mill. under low temperature stress, photosynthesis-related genes were screened and the molecular mechanism were analyzed for this species growing in Harbin, northeast of China. RNA-seq technique and photosynthetic physiology measurement were performed under 20°C, 10°C, and 0°C in this study. The results showed that the observing modified rectangular hyperbola mode could accurately reflect the light-response processes under low temperature stress and the low temperature reduced the light energy utilization of L. angustifolia. The stomatal conductance decreased with the temperature dropping, which was associated with the up-regulation of LaBAM1s, LaMPK4-1 and LaMMK2. The up-regulation of LaMPK4-1 and LaMMK2 was beneficial for ROS scavenging. The improvement of cold resistance in L. angustifolia was related to the up-regulated expression of LaFBA and LaOMTs and down-regulated expression of LaGAPAs, LaGOX, and LaTKL1s with the temperature decreasing. The up-expression of LaPSY at 10°C than it at 20°C could protect the photosynthetic organs from oxidative damage. Moreover, the photosynthetic rates at 10°C and 0°C were close to the measured values, which was related to the interactions of RCA with SBPase and Rubisco with SBPase. These findings could provide a theoretical reference for further exploring the cold tolerance mechanism of L. angustifolia, as an important aromatic plant resource, and promoting its cultivation and distribution in the northeast of China.

Molecular Mechanism of Response and Adaptation of Antioxidant Enzyme System to Salt Stress in Leaves of Gymnocarpos przewalskii

The antioxidant enzyme system is the main defense system responsible for maintaining cellular reactive oxygen species (ROS) homeostasis and normal plant growth and development after saline stress. In this study, we identified and characterized the members of the SOD, APX and CAT gene families of the antioxidant enzyme system in Gymnocarpos przewalskii, using plant physiology and molecular biology methods, and analyzed the pattern of enzyme activity in response to NaCl stress. It was found that seven, six and two genes of SOD, APX and CAT gene families, respectively, were expressed in the leaf tissue of G. przewalskii, in which most of the genes were significantly upregulated under NaCl stress, and the enzymatic activities were in accordance with the gene expression. Three positive selection sites in the GpCAT1 gene can increase the hydrophilicity of the GpCAT1 protein, increase the volume of the active site and increase the affinity for H2O2, thus improving the catalytic efficiency of GpCAT1. The results of the present study provide new insights for further investigations of the evolution and function of the SOD, APX and CAT gene families in G. przewalskii and their essential roles under salt stress, and the findings will be useful for revealing the molecular mechanism of salt tolerance and breeding of salt-tolerant plants.

Comprehensive Evaluation and Transcriptome Analysis Reveal the Salt Tolerance Mechanism in Semi-Wild Cotton (Gossypium purpurascens)

Elevated salinity significantly threatens cotton growth, particularly during the germination and seedling stages. The utilization of primitive species of Gossypium hirsutum, specifically Gossypium purpurascens, has the potential to facilitate the restoration of genetic diversity that has been depleted due to selective breeding in modern cultivars. This investigation evaluated 45 G. purpurascens varieties and a salt-tolerant cotton variety based on 34 morphological, physiological, and biochemical indicators and comprehensive salt tolerance index values. This study effectively identified a total of 19 salt-tolerant and two salt-resistant varieties. Furthermore, transcriptome sequencing of a salt-tolerant genotype (Nayanmian-2; NY2) and a salt-sensitive genotype (Sanshagaopao-2; GP2) revealed 2776, 6680, 4660, and 4174 differentially expressed genes (DEGs) under 0.5, 3, 12, and 24 h of salt stress. Gene ontology enrichment analysis indicated that the DEGs exhibited significant enrichment in biological processes like metabolic (GO:0008152) and cellular (GO:0009987) processes. MAPK signaling, plant-pathogen interaction, starch and sucrose metabolism, plant hormone signaling, photosynthesis, and fatty acid metabolism were identified as key KEGG pathways involved in salinity stress. Among the DEGs, including NAC, MYB, WRKY, ERF, bHLH, and bZIP, transcription factors, receptor-like kinases, and carbohydrate-active enzymes were crucial in salinity tolerance. Weighted gene co-expression network analysis (WGCNA) unveiled associations of salt-tolerant genotypes with flavonoid metabolism, carbon metabolism, and MAPK signaling pathways. Identifying nine hub genes (MYB4, MYB105, MYB36, bZIP19, bZIP43, FRS2 SMARCAL1, BBX21, F-box) across various intervals offered insights into the transcriptional regulation mechanism of salt tolerance in G. purpurascens. This study lays the groundwork for understanding the important pathways and gene networks in response to salt stress, thereby providing a foundation for enhancing salt tolerance in upland cotton.