Sugar Metabolism Pathways Research Articles

Photosynthetic characteristics and genetic mapping of a yellow-green leaf mutant jym165 in soybean

BackgroundLeaves are important sites for photosynthesis and can convert inorganic substances into organic matter. Photosynthetic performance is an important factor affecting crop yield. Leaf colour is closely related to photosynthesis, and leaf colour mutants are considered an ideal material for studying photosynthesis.ResultsWe obtained a yellow-green leaf mutant jym165, using ethyl methane sulfonate (EMS) mutagenesis. Physiological and biochemical analyses indicated that the contents of chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll in the jym165 mutant decreased significantly compared with those in Jiyu47 (JY47). The abnormal chloroplast development of jym165 led to a decrease in net photosynthetic rate and starch content compared with that of JY47. However, quality traits analysis showed that the sum of oil and protein contents in jym165 was higher than that in JY47. In addition, the regional yield (seed spacing: 5 cm) of jym165 increased by 2.42% compared with that of JY47 under high planting density. Comparative transcriptome analysis showed that the yellow-green leaf phenotype was closely related to photosynthesis and starch and sugar metabolism pathways. Genetic analysis suggests that the yellow-green leaf phenotype is controlled by a single recessive nuclear gene. Using Mutmap sequencing, the candidate regions related of leaf colour was narrowed to 3.44 Mb on Chr 10.ConclusionsAbnormal chloroplast development in yellow-green mutants leads to a decrease in the photosynthetic pigment content and net photosynthetic rate, which affects the soybean photosynthesis pathway and starch and sugar metabolism pathways. Moreover, it has the potentiality to increase soybean yield under dense planting conditions. This study provides a useful reference for studying the molecular mechanisms underlying photosynthesis in soybean.

ApCarE4 and ApPOD3 participate in the adaptation of pea aphids to different alfalfa varieties

The adaptability of insects to hosts has long been a focal point in the study of insect-plant interactions. The pea aphid (Acythosiphon pisum), a significant pest of numerous leguminous crops, not only inflicts direct economic losses but also disseminates various plant viruses. To understand how pea aphids adapt to diverse alfalfa varieties. We analyzed the differentially expressed genes (DEGs) of pea aphids in distinct alfalfa varieties using transcriptome sequencing, and subsequently conducted functional validation of these genes. Comparative analysis between pea aphids feeding on susceptible and resistant strains revealed that DEGs in aphids feeding on resistant strains were primarily associated with transcriptional enrichment in the sugar, amino acid, protein, and lipid metabolism pathways. Fourteen DEGs related to adaptation of the pea aphid to alfalfa were chosen, including five carboxylesterases (CarE), four cytochrome P450s, three glutathione S-transferases, and two peroxidases (POD). RT-qPCR results indicated significant up-regulation of two carboxylesterase genes and two peroxidase genes after 24 h of feeding resistant alfalfa (Gannong 5, GN5) compared to the susceptible varieties (Hunter River, LRH), particularly highlighting the high expression levels of ApCarE4 and ApPOD3. Simultaneously, RNAi-induced knockdown of ApCarE4 and ApPOD3 led to a higher mortality of pea aphids in the alfalfa Hunter River. These results indicate that ApPOD3 and ApCarE4 are involved in the detoxification of metabolic functions in the adaptation of pea aphids to host switching. These findings contribute to the understanding of pea aphid adaptation to host plants and lay a foundation for further exploration of the physiological roles of carboxylesterase and peroxidase genes in pea aphids.

Comparative metabolomics reveals the mechanism for the high GA4 production in Gibberella fujikuroi CGMCC 17793

With unique advantages, gibberellin GA4 has broad application prospects. To explore the regulatory mechanism for the biosynthesis of GA4, we combined liquid chromatography-mass spectrometry (LC-MS)-based metabolomics with principal component analysis (principal component analysis, PCA) and partial least squares-discriminant analysis (PLS-DA) to screen and identify the differential metabolites between the GA4-producing strains S (industrial high-yield strain CGMCC 17793) and wild-type strain Y (NRRL 13620) of Gibberella fujikuroi fermented for the same time and the differential metabolites of strain S fermented for different time periods. KEGG and MBROLE 2.0 were used to analyze the metabolic pathways involving the differential metabolites. The results showed that compared with strain Y, strain S significantly upregulated and downregulated 107 and 66, 136 and 47, and 94 and 65 metabolites on days 3, 6, and 9, respectively. Compared with that on day 3 of fermentation, strain S upregulated 29 metabolites and downregulated 40 metabolites on day 6 and upregulated 52 metabolites and downregulated 67 metabolites on day 9. The differential metabolites between strain S and strain Y after fermentation for the same time were mainly enriched in amino acid metabolism, tricarboxylic acid (TCA) cycle, and terpenoid biosynthesis. The differential metabolites of strain S after fermentation for different time periods were mainly enriched in amino acid and sugar metabolism pathways. Pathway annotation results indicated that strain S increased the production of acetyl-CoA by promoting amino acid and sugar metabolism and TCA cycle, thereby enhancing the mevalonic acid pathway and increasing the content of isopentenyl pyrophosphate (IPP), a precursor for the synthesis of terpenoids, which ultimately led to increased GA4 production. This study explored the metabolic rules of Gibberella fujikuroi GA4, providing a theoretical basis for regulating Gibberella fujikuroi to improve GA4 production.

Sustained carbon import supports sugar accumulation and anthocyanin biosynthesis during fruit development and ripening in blueberry (Vaccinium ashei)

Fruit ripening is a highly coordinated process involving molecular and biochemical changes that collectively determine fruit quality. The underlying metabolic programs and their transitions leading to fruit ripening remain largely under-characterized in blueberry (Vaccinium sp.), which exhibits atypical climacteric behavior. In this study, we focused on sugar, acid and anthocyanin metabolism in two rabbiteye blueberry cultivars, Premier and Powderblue, during fruit development and ripening. Concentrations of the three major sugars, sucrose (Suc), glucose (Glc), and fructose (Fru) increased steadily during fruit development leading up to ripening, and increased dramatically by around 2-fold in ‘Premier’ and 2- to 3-fold in ‘Powderblue’ during the final stage of fruit ripening. Starch concentration was very low throughout fruit development in both cultivars indicating that it does not serve the role of a major transitory carbon (C) storage form in blueberry fruit. Together, these patterns indicate continued import of C, likely in the form of Suc, throughout blueberry fruit development. Concentrations of the predominant acids, malate and quinate, decreased during ripening, and may contribute to increased shikimate biosynthesis which, in-turn, allows for downstream phenylpropanoid metabolism leading to anthocyanin synthesis. Consistently, anthocyanin concentrations were highest in fully ripened blue fruit. Weighted gene co-expression network analysis (WGCNA) was performed using a ‘Powderblue’ fruit ripening transcriptome and targeted fruit metabolite concentration data. A ‘dark turquoise’ module positively correlated with sugars and anthocyanins, and negatively correlated with acids (malate, quinate), was identified. Gene Ontology (GO) enrichment analysis of this module identified transcripts related to sugar, acid, and phenylpropanoid metabolism pathways. Among these, increased transcript abundance of a VACUOLAR INVERTASE during ripening was consistent with sugar storage in the vacuole. In general, transcript abundance of the glycolysis pathway genes was upregulated during ripening. The transcript abundance of PHOSPHOENOLPYRUVATE (PEP) CARBOXYKINASE increased during fruit ripening and was negatively correlated with malate concentration, suggesting increased malate conversion to PEP, which supports anthocyanin production during fruit ripening. This was further supported by the co-upregulation of several anthocyanin biosynthesis-related genes. Together, this study provides insights into important metabolic programs, and their underlying gene expression patterns during fruit development and ripening in blueberry.

Analyzing the temporal response mechanisms of the vascular bundles formation of grafted cucumber to different light intensity modes: A joint transcriptomic and metabolomic approach

In plant grafting, the reconnection of vascular bundles between the rootstock and scion not only establishes functional xylem and phloem connections, but also signifies the completion of graft healing. In our previous studies focused on early-stage morphology and physiology of grafted seedlings, we have demonstrated that utilizing light intensities of 50-100-150 μmol/(m2·s) during days 1-3, 4-6, and 7-9 optimizes cucumber/pumpkin graft healing. To further explore the underlying mechanisms, we investigate light intensity regimes: 50-100-100 μmol/(m2·s) and 50-100-150 μmol/(m2·s) during the same time frames (days 1-3, 4-6, and 7-9 after grafting), denoted as CK and T treatments. Initially, we observe histological characteristics of vascular bundle formation under these conditions, followed by the analyses of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione peroxidase (GSH-Px) enzyme activities, ascorbic acid (AsA) content in the antioxidant system, and the sequencing of transcriptome and metabolome. It is found that grafted seedlings under the T treatment achieve faster vascular bundle reconnection and shorter healing process compared to those under the CK treatment. Enzyme activities (POD, SOD, GSH-Px) increase over time under both light regimes, while CAT activity and AsA content decrease. Notably, by the 9th day, the T treatment (T9d) exhibits higher SOD, POD and CAT activities than the CK treatment (CK9d). Our findings indicate that increasing light intensity during the days 7-9 after grafting can mitigate oxidative damage at the grafting site and benefit vascular bundle reconnection. Transcriptome and metabolome analyses show the up-regulations of Cinnamaldehyde in the phenylpropanoid biosynthesis pathway, the PHGDH gene and L-Homocysteine in the cysteine and methionine metabolism pathway under T treatment in the days 7-9 after grafting. These enhance the antioxidant enzyme activities and reduce the oxidative damage to the grafting site. Additionally, GAE-related genes, and metabolites D-Xylose and Undecaprenyl phosphatealpha-L-Ara4FN in the amino sugar and nucleotide sugar metabolism pathways are also up-regulated under T treatment. The ethylene responsive factor (ERF) transcription factor CsaRAP2.3 positively regulates Undecaprenyl phosphatealpha-L-Ara4FN expression, promoting cell wall synthesis and therefore accelerating vascular bundle reconnection. In summary, during the vascular bundle formation period of cucumber graft healing, both light intensity modes coordinate regulation of phenylpropanoid biosynthesis, cysteine and methionine metabolism, amino sugar and nucleoside sugar metabolism, and ERF transcription factors, promoting graft healing from both stress resistance and cell wall synthesis. Furthermore, building upon the light intensity applied during the callus formation phase, increasing the light intensity during the vascular bundle formation period can significantly enhance cell wall synthesis, thus expediting the graft healing process. Nonetheless, the generalizability of these research findings to other grafting techniques and species requires further investigation.

Identification and characterisation of 'No apical meristem; Arabidopsis transcription activation factor; Cup-shape cotyledon' (NAC) family transcription factors involved in sugar accumulation and abscisic acid signalling in grape (Vitis vinifera).

The 'No apical meristem; Arabidopsis transcription activation factor; Cup-shape cotyledon' (NAC) transcription factors are pivotal in plant development and stress response. Sucrose-non-fermenting-related protein kinase 1.2 (SnRK1) is a key enzyme in glucose metabolism and ABA signalling. In this study, we used grape (Vitis vinifera ) calli to explore NAC's roles in sugar and ABA pathways and its relationship with VvSnRK1.2 . We identified 19 VvNACs highly expressed at 90days after blooming, coinciding with grape maturity and high sugar accumulation, and 11 VvNACs randomly selected from 19 were demonstrated in response to sugar and ABA treatments. VvNAC26 showed significant response to sugar and ABA treatments, and its protein, as a nucleus protein, had transcriptional activation in yeast. We obtained the overexpression (OE-VvNAC26 ) and RNA-inhibition (RNAi-VvNAC26 ) of VvNAC26 in transgenic calli by Agrobacterium tumefaciens -mediated transformation. We found that VvNAC26 negatively influenced fructose content. Under sugar and ABA treatments, VvNAC26 negatively influenced the expression of most sugar-related genes, while positively influencing the expression of most ABA pathway-related genes. Dual-luciferase reporter experiments demonstrated that VvNAC26 significantly upregulates VvSnRK1.2 promoter expression in tobacco (Nicotiana benthamiana ) leaves, although this process in grape calli requires ABA. The levels of sugar content, sugar-related genes, and ABA-related genes fluctuated significantly in OE-VvNAC26 +RNAi-VvSnRK1.2 and OE-VvSnRK1.2 +RNAi-VvNAC26 transgenic calli. These findings indicated that VvNAC26 regulates sugar metabolism and ABA pathway, displaying synergistic interactions with VvSnRK1.2 .

Transcriptomic and metabolomic investigations of methyl jasmonate-mediated enhancement of low temperature stress resistance in Cassia obtusifolia L.

Low temperature stress negatively impacts plant growth and development, reducing crop yields by disrupting metabolite production and accumulation. Cassia obtusifolia L., a widely cultivated medicinal plant in subtropical regions, is particularly vulnerable to such stress. Methyl jasmonate (MeJA) regulates plant growth, defense mechanisms, and secondary metabolite production. This study investigated how C. obtusifolia responds to low temperature stress under MeJA treatment using transcriptomic and metabolomic approaches. MeJA treatment upregulated several transcription factor families, including APE/ERF-ERF, WRKY, NAC, and MYB-related, which modulated the plant's response to cold stress. These transcription factors influenced the expression of genes involved in glycolysis, sugar metabolism, and amino acid pathways, contributing to the plant's adaptive responses. Differentially expressed genes were associated with key metabolic processes such as flavonoid biosynthesis, ribosome function, glycolysis/gluconeogenesis, and sugar metabolism. Using H-NMR and LC-MS techniques, we observed that MeJA induced the accumulation of sugars and amino acids in the leaves of C. obtusifolia seedlings under cold stress, while levels of three flavonoid compounds Isoliquiritigenin, Kaempferol-7-O-glucoside, and Phloretin significantly decreased. Enrichment analysis indicated that MeJA modulates the biosynthetic pathways of these compounds in a dose-dependent manner. Integrating metabolomic and transcriptomic data further elucidated alterations in the flavonoid biosynthetic network and other metabolic pathways under low temperature stress. These findings offer insights into the molecular mechanisms underlying flavonoid synthesis and other metabolic adjustments in C. obtusifolia under MeJA treatment.

MoHG1 Regulates Fungal Development and Virulence in Magnaporthe oryzae

Magnaporthe oryzae causes rice blast disease, which threatens global rice production. The interaction between M. oryzae and rice is regarded as a classic model for studying the relationship between the pathogen and the host. In this study, we found a gene, MoHG1, regulating fungal development and virulence in M. oryzae. The ∆Mohg1 mutants showed more sensitivity to cell wall integrity stressors and their cell wall is more easily degraded by enzymes. Moreover, a decreased content of chitin but higher contents of arabinose, sorbitol, lactose, rhamnose, and xylitol were found in the ∆Mohg1 mutant. Combined with transcriptomic results, many genes in MAPK and sugar metabolism pathways are significantly regulated in the ∆Mohg1 mutant. A hexokinase gene, MGG_00623 was downregulated in ∆Mohg1, according to transcriptome results. We overexpressed MGG_00623 in a ∆Mohg1 mutant. The results showed that fungal growth and chitin contents in MGG_00623-overexpressing strains were restored significantly compared to the ∆Mohg1 mutant. Furthermore, MoHG1 could interact with MGG_00623 directly through the yeast two-hybrid and BiFC. Overall, these results suggest that MoHG1 coordinating with hexokinase regulates fungal development and virulence by affecting chitin contents and cell wall integrity in M. oryzae, which provides a reference for studying the functions of MoHG1-like genes.

Ziziphus Jujube Polysaccharides inhibit over-abundance of fecal butyric acid in mildly stressed growing mice to ameliorate depression-like behavior

The microbial-gut-brain axis is the main pathway that induces depression in adolescents. In Chinese medicine, Ziziphus Jujube Polysaccharides (ZJP) are recognized for their capacity to modulate gut microbiota and bolster immune function, suggesting their potential as a therapeutic agent for mitigating youth depression. In this study, a 44 d chronic unpredictable mild stress (CUMS) model was used to investigate how ZJP alleviates depression-like behavior in male C57BL/6 mice. The administration of ZJP ameliorated depression-like behavior, down-regulated serum levels of TNF-α, IL-1β, IL-2, IL-6, and up-regulated hippocampal 5-HT. Correlation analysis revealed that fecal butyric acid (BA) concentration was positively correlated with depression-like behavior index (P＜0.05). ZJP modified the gut microbiota by replenishing deficient saccharides (fructose, galactose, rhamnose, arabinose), diminishing the prevalence of SCFA-producing bacteria (Alistipes, Lachnospiraceae, Colidextribacter). Additionally, ZJP decreased the gene abundance of the sugar and SCFA metabolism pathways, and related enzymes in the gut of model mice, thereby reversing butyrate enrichment and ameliorating associated depression-like behavior. In summary, ZJP stabilized the intestinal microbiota structure and balanced the BA metabolism in CUMS mice by regulating the metabolism of gut microbiota-sugar-SCFAs, thereby improving depression-like behavior.

Transcriptional and metabolic analyses of leaf responses to low phosphorus levels in quinoa heading stage

Quinoa, a globally significant crop, is highly susceptible to low phosphorus stress, which can significantly impair its production and quality. Therefore, it is necessary to study the molecular mechanisms of quinoa's response to low phosphorus stress must be investigated. In this study, we identified a total of 14,824 genes and 1788 metabolites using transcriptomic and metabolomic techniques. Compared to the control group, 1378 and 8548 differentially expressed genes (DEGs), as well as 210 and 362 differentially accumulated metabolites (DAMs), were identified in the low phosphorus-treated groups, respectively. Bioinformatics analysis showed that these DEGs and DAMs are associated with various biological processes,for instance glycolysis, starch and sugar metabolism, pyruvate metabolism, glycerophospholipid metabolism, photosynthetic biosequestration, galactose metabolism, and citric acid cycle. Moreover, the results of the co-expression analysis highlighted interactions among DEGs and DAMs, particularly in the associated path to starch and sugar metabolism, glycerophospholipid metabolism, photosynthetic biosequestration, and glycolytic metabolic pathways. These results suggest that quinoa responds to low-phosphorus stress through these metabolic pathways. Overall, this study enhances our understanding of quinoa's mechanism in response to phosphorus deficiency and provides a reference for molecular design breeding of quinoa adapted to phosphorus deficiency.

Transcriptome and weighted gene co-expression network analyses reveal key genes and pathways involved in early fruit ripening in Citrus sinensis

BackgroundThe fruit ripening period is an important target trait in fruit tree crop breeding programs. Thus, citrus tree breeders seek to develop extreme early ripening cultivars that allow optimization of citrus maturation periods. In this study, we explored the regulatory network involved in fruit ripening in Citrus sinensis using the ‘Newhall’ navel orange variety and its early-ripening mutant, ‘Gannanzao’. This research will provide a basis for further research on important signaling pathways, gene functions and variety breeding of Citrus sinensis related to fruit ripening period.ResultsPhysiological analyses suggested that early fruit ripening in ‘Gannanzao’ is regulated by early accumulation of abscisic acid (ABA), persistently high levels of jasmonic acid (JA), and higher sucrose content in the pericarp. Pericarp samples from ‘Gannanzao’ and ‘Newhall’ navel oranges were sampled for RNA sequencing analysis at 180, 200, and 220 days after flowering; 1430 differentially expressed genes (DEGs) were identified. Functional enrichment analysis indicated that these DEGs were mainly enriched in the plant hormone signal transduction and sugar metabolism pathways, as well as other pathways related to fruit ripening. Important DEGs associated with fruit ripening in ‘Gannanzao’ included genes involved in ABA and JA metabolism and signal transduction, as well as sugar metabolism. Weighted gene co-expression network analysis showed that the deep pink module had the strongest correlations with ABA content, JA content, and early ripening. Based on gene functionality and gene expression analyses of 37 genes in this module, two candidate hub genes and two ethylene response factor 13 (ERF13) genes (Cs_ont_5g000690 and Cs_ont_5g000700) were identified as key genes regulated by ABA and JA signaling. These findings will help to clarify the mechanisms that underlie early citrus fruit ripening and will lead to the development of excellent genetic resources for further breeding of extreme early-ripening varieties.ConclusionsThrough analyses of the ‘Newhall’ navel orange cultivar and its early-ripening mutant ‘Gannanzao’, we identified genes involved in ABA and JA metabolism, signal transduction, and sugar metabolism that were related to fruit ripening. Among these, two ERF13 genes were inferred to be key genes in the regulation of fruit ripening. These findings provide insights into the genetic architecture related to early fruit ripening in C. sinensis.

Effects of yellow mealworm (Tenebrio molitor) larvae meal on the growth performance, serum biochemical parameters and caecal metabolome in broiler chickens

The goal of this study was to evaluate the effects of Tenebrio molitor (TM) larvae meal on the growth performance, serum biochemical parameters and caecal metabolome of broiler chickens. A total of 600 1-d-old male Liangfenghua broilers were randomly assigned to five equal groups with 5 replicates and 24 birds in each replicate. The dietary treatments were as follows: the control group (TM0 group) was fed a basal diet, and the experimental groups were fed experimental diets in which 3% (TM3 group), 5% (TM5 group), 7% (TM7 group) and 9% (TM9 group) TM larvae meal included in the basal diet, respectively. The feeding period was 70 d. The results showed that body weight (BW) and average daily gain (ADG) significantly increased (p < 0.05) in response to dietary 3% TM larvae meal supplementation at the age of 70 d. Serum concentrations of triglyceride (TG) and serum activity of aspartate aminotransferase (AST) decreased (p < 0.05) in 3% TM larvae meal-fed broilers. UHPLC-MS/MS-based metabolomics analysis revealed that a total of 55 significantly different metabolites were obtained in the caecal contents of dietary TM larvae meal supplemented broilers. The relative contents of 28 metabolites such as trans-4-hydroxy-L-proline, thymine and retinoic acid were significantly up-regulated (FC > 1.5) and the relative contents of 27 metabolites like prostaglandin F2α, glucocorticoids and prostaglandin E2 were significantly down-regulated (FC < 0.667) in the TM3 group. The main altered pathways were clustered into arachidonic acid metabolism, primary bile acid metabolism and propionic acid metabolism. In conclusion, the results indicated that supplementation of 3% TM larvae meal can improve growth performance, reduce the activity of serum AST and the content of TG, and regulation of the pathways of lipid, amino acid, and sugar metabolism in the caecum of broilers by improving nutrient digestion and absorption.

Overexpression of a transcription factor MdWRKY126 altered soluble sugar accumulation in apple and tomato fruit

The compositions and contents of soluble sugars highly determine the flavor and quality of flshy fruits. In the present study, we found that the overexpression of transcription factor MdWRKY126 localized on the nucleus enhanced sucrose concentration while decreased fructose and glucose concentration in transgenic apple calli and ripening tomato fruits. To comprehensively understand the effects of the MdWRKY126 on the content of various soluble sugars in apple and tomato fruits, enzyme activities and related essential genes associated with the sugar metabolism and transportation pathway in MdWRKY126-overrexpressed apple and tomato lines were analyzed. The results indicated that the overexpression of MdWRKY126 upregulated sucrose phosphate synthase (SPS) activity and the gene expression levels of SPS and sucrose transporter SUT, which was conducive to a large accumulation of sucrose in fruit cells. Meanwhile, MdWRKY126 overexpression downregulated the activity of enzymes involved in sucrose decomposition including cell wall invertase (CWINV), sucrose synthase (SUSY) and the corresponding gene expressions, as well as inhibited the expression levels of hexose transporter (HTs) and tonoplast sugar transporter (TSTs) that transport hexose into vacuoles, resulting in a reduced hexose level in apple calli and tomato fruit. These findings enrich our understanding of the metabolism and regulation of soluble sugars in apple fruits.

Insights into the Correlation between Microbial Community Succession and Pericarp Degradation during Pepper (Piper nigrum L.) Peeling Process via Retting.

White pepper, used both as a seasoning in people's daily diets and as a medicinal herb, is typically produced by removing the pericarp of green pepper through the retting process. However, the mechanism of the retting process for peeling remains unclear. Therefore, this study aimed to investigate the changes in physicochemical factors, microbial community succession effects, and metabolites of the pepper pericarp during the pepper peeling process. The findings indicated that pre-treatment involving physical friction before the retting process effectively reduced the production time of white pepper. During the retting process, the pectinase activity increased, leading to a decrease in the pectin content in the pepper pericarp. There was a significant correlation observed between the changes in pH, pectin content, and peeling rate and the Shannon diversity index of bacteria and fungi. Prevotella, Lactococcus, and Candida were the dominant microbial genera during the retting. The functional predictions suggested that the monosaccharides degraded from the pepper pericarp could have been utilized by microbes through sugar metabolism pathways. Metabolomic analysis showed that the metabolic pathways of carbohydrates and amino acids were the main pathways altered during the pepper peeling process. The verification experiment demonstrated that the degradation of pectin into galacturonic acid by polygalacturonase was identified as the key enzyme in shortening the pepper peeling time. The structure of the pepper pericarp collapsed after losing the support of pectin, as revealed by scanning electron microscopy. These results suggest that the decomposition of the pepper pericarp was driven by key microbiota. The succession of microbial communities was influenced by the metabolites of the pepper pericarp during retting. These findings provide new insights into the retting process and serve as an important reference for the industrial production of white pepper.

Similar chilling response of dormant buds in potato tuber and woody perennials.

Bud dormancy is a survival strategy that plants have developed in their native habitats. It helps them endure harsh seasonal changes by temporarily halting growth and activity until conditions become more favorable. Research has primarily focused on bud dormancy in tree species and the ability to halt growth in vegetative tissues, particularly in meristems. Various plant species, such as potato, have developed specialized storage organs, enabling them to become dormant during their yearly growth cycle. Deciduous trees and potato tubers exhibit a similar type of bud endodormancy, where the bud meristem will not initiate growth, even under favorable environmental conditions. Chilling accumulation activates C-repeat/dehydration responsive element binding (DREB) factors (CBFs) transcription factors that modify the expression of dormancy-associated genes. Chilling conditions shorten the duration of endodormancy by influencing plant hormones and sugar metabolism, which affect the timing and rate of bud growth. Sugar metabolism and signaling pathways can interact with abscisic acid, affecting the symplastic connection of dormant buds. This review explores how chilling affects endodormancy duration and explores the similarity of the chilling response of dormant buds in potato tubers and woody perennials.

New insight into protective effect against oxidative stress and biosynthesis of exopolysaccharides produced by Lacticaseibacillus paracasei NC4 from fermented eggplant.

Fermented eggplant is a traditional fermented food, however lactic acid bacteria capable of producing exopolysaccharide (EPS) have not yet been exploited. The present study focused on the production and protective effects against oxidative stress of an EPS produced by Lacticaseibacillus paracasei NC4 (NC4-EPS), in addition to deciphering its genomic features and EPS biosynthesis pathway. Among 54 isolates tested, strain NC4 showed the highest EPS yield and antioxidant activity. The maximum EPS production (2.04 ± 0.11g/L) was achieved by culturing in MRS medium containing 60g/L sucrose at 37°C for 48h. Under 2mM H2O2 stress, the survival of a yeast model Saccharomyces cerevisiae treated with 0.4mg/mL NC4-EPS was 2.4-fold better than non-treated cells, which was in agreement with the catalase and superoxide dismutase activities measured from cell lysates. The complete genome of NC4 composed of a circular chromosome of 2,888,896bp and 3 circular plasmids. The NC4 genome comprises more genes with annotated function in nitrogen metabolism, phosphorus metabolism, cell division and cell cycle, and iron acquisition and metabolism as compared to other reported L. paracasei. Of note, the eps gene cluster is not conserved across L. paracasei. Pathways of sugar metabolism for EPS biosynthesis were proposed for the first time, in which gdp pathway only present in few plant-derived bacteria was identified. These findings shed new light on the cell-protective activity and biosynthesis of EPS produced by L. paracasei, paving the way for future efforts to enhance yield and tailor-made EPS production for food and pharmaceutical industries.

Effects of polyethylene and biodegradable microplastics on the physiology and metabolic profiles of dandelion

Biodegradable plastics, such as poly(butylene adipate terephthalate) (PBAT) and polylactic acid (PLA), are potential alternatives to conventional polyethylene (PE), both of which are associated with the production of microplastics (MPs). However, the toxicity of these compounds on medicinal plants and their differential effects on plant morphophysiology remain unclear. This study supplemented soils with MPs sized at 200 μm at a rate of 1% w/w and incubated them for 50 days to investigate the impact of MPs on the growth and metabolites of dandelion (Taraxacum mongolicum Hand.-Mazz.). The results demonstrated that the investigated MPs decreased the growth of dandelion seedlings, induced oxidative stress, and altered the activity of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase). Based on the comprehensive toxicity assessment results, the ecological toxicity was in the following order: PE MPs > PBAT MPs > PLA MPs. Metabolomics analyses revealed metabolic reprogramming in dandelion plants, leading to the enrichment of numerous differentially accumulated metabolites (DAMs) in the leaves. These pathways include carbohydrate metabolism, energy metabolism, and biosynthesis of secondary metabolites, suggesting that dandelions respond to MP stress by enhancing the activity of sugar, organic acid, and amino acid metabolic pathways. In addition, phenolic acids and flavonoids are critical for maintaining the balance in the antioxidant defense system. Our results provide substantial insights into the toxicity of biodegradable MPs to plants and shed light on plant defense and adaptation strategies. Further assessment of the safety of biodegradable MPs in terrestrial ecosystems is essential to provide guidance for environmentally friendly management.

Role of sugars in the apical hook development of Arabidopsis etiolated seedlings.

The sugar supply in the medium affects the apical hook development of Arabidopsis etiolated seedlings. In addition, we provided the mechanism insights of this process. Dicotyledonous plants form an apical hook structure to shield their young cotyledons from mechanical damage as they emerge from the rough soil. Our findings indicate that sugar molecules, such as sucrose and glucose, are crucial for apical hook development. The presence of sucrose and glucose allows the apical hooks to be maintained for a longer period compared to those grown in sugar-free conditions, and this effect is dose-dependent. Key roles in apical hook development are played by several sugar metabolism pathways, including oxidative phosphorylation and glycolysis. RNA-seq data revealed an up-regulation of genes involved in starch and sucrose metabolism in plants grown in sugar-free conditions, while genes associated with phenylpropanoid metabolism were down-regulated. This study underscores the significant role of sugar metabolism in the apical hook development of etiolated Arabidopsis seedlings.

Grape SnRK2.7 Positively Regulates Drought Tolerance in Transgenic Arabidopsis.

In this study, we obtained and cloned VvSnRK2.7 by screening transcriptomic data to investigate the function of the grape sucrose non-fermenting kinase 2 (SnRK2) gene under stress conditions. A yeast two-hybrid (Y2H) assay was used to further screen for interaction proteins of VvSnRK2.7. Ultimately, VvSnRK2.7 was heterologously expressed in Arabidopsis thaliana, and the relative conductivity, MDA content, antioxidant enzyme activity, and sugar content of the transgenic plants were determined under drought treatment. In addition, the expression levels of VvSnRK2.7 in Arabidopsis were analyzed. The results showed that the VvSnRK2.7-EGFP fusion protein was mainly located in the cell membrane and nucleus of tobacco leaves. In addition, the VvSnRK2.7 protein had an interactive relationship with the VvbZIP protein during the Y2H assay. The expression levels of VvSnRK2.7 and the antioxidant enzyme activities and sugar contents of the transgenic lines were higher than those of the wild type under drought treatment. Moreover, the relative conductivity and MDA content were lower than those of the wild type. The results indicate that VvSnRK2.7 may activate the enzyme activity of the antioxidant enzyme system, maintain normal cellular physiological metabolism, stabilize the berry sugar metabolism pathway under drought stress, and promote sugar accumulation to improve plant resistance.

Transcriptomic and metabolomic analyses reveal the importance of ethylene networks in mulberry fruit ripening

Mulberry (Morus alba L.) is a climacteric and highly perishable fruit. Ethylene has been considered to be an important trigger of fruit ripening process. However, the role of ethylene in the mulberry fruit ripening process remains unclear. In this study, we performed a comprehensive analysis of metabolomic and transcriptomic data of mulberry fruit and the physiological changes accompanying the fruit ripening process. Our study revealed that changes in the accumulation of specific metabolites at different stages of fruit development and ripening were closely correlated to transcriptional changes as well as underlying physiological changes and the development of taste biomolecules. The ripening of mulberry fruits was highly associated with the production of endogenous ethylene, and further application of exogenous ethylene assisted the ripening process. Transcriptomic analysis revealed that differential expression of diverse ripening-related genes was involved in sugar metabolism, anthocyanin biosynthesis, and cell wall modification pathways. Network analysis of transcriptomics and metabolomics data revealed that many transcription factors and ripening-related genes were involved, among which ethylene-responsive transcription factor 3 (MaERF3) plays a crucial role in the ripening process. The role of MaERF3 in ripening was experimentally proven in a transient overexpression assay in apples. Our study indicates that ethylene plays a vital role in modulating mulberry fruit ripening. The results provide a basis for guiding the genetic manipulation of mulberry fruits towards sustainable agricultural practices and improve post-harvest management, potentially enhancing the quality and shelf life of mulberry fruits for sustainable agriculture and forestry.