Expression Of Biosynthesis-related Genes Research Articles

Integrated multi-omics investigation revealed the importance of phenylpropanoid metabolism in the defense response of Lilium regale Wilson to Fusarium wilt

Abstract Lilies (genus: Lilium) play a significant role in the global cut-flower industry, but they are highly susceptible to Fusarium wilt caused by Fusarium oxysporum. However, Lilium regale, a wild lily species, exhibits remarkable resistance to F. oxysporum. To investigate the quantitative resistance of L. regale to Fusarium wilt, a comprehensive multi-omics analysis was conducted. Upon inoculation with F. oxysporum, L. regale roots showed a significant accumulation of phenylpropane metabolites, including lignin precursors, flavonoids, and hydroxycinnamic acids. These findings were consistent with the up-regulated expression of phenylpropanoid biosynthesis-related genes encoding various enzymes, as revealed by transcriptomics and proteomics analyses. Furthermore, metabolomics and proteomics data demonstrated differential activation of monoterpenoid and isoquinoline alkaloid biosynthesis. Colorimetry and high-performance liquid chromatography analyses revealed significantly higher levels of total flavonoids, lignin, ferulic acid, phlorizin, and quercetin contents in L. regale scales compared to susceptible lily ‘Siberia’ scales during F. oxysporum infection. These phenylpropanes exhibited inhibitory effects on F. oxysporum growth and suppressed the expression of pathogenicity-related genes. Transcriptional regulatory network analysis suggested that ethylene-responsive transcription factors (ERFs) may positively regulate phenylpropanoid biosynthesis. Therefore, LrERF4 was cloned and transiently overexpressed in the Fusarium wilt-susceptible Oriental hybrid lily, ‘Siberia’. The overexpression of LrERF4 resulted in increased levels of total flavonoids, lignin, ferulic acid, phlorizin, and quercetin, while the silencing of LrERF4 in L. regale through RNAi had opposite effect. In conclusion, phenylpropanoid metabolism plays a crucial role in the defense response of L. regale against Fusarium wilt, with LrERF4 acting as a positive regulator of phenylpropane biosynthesis.

The Effect of Light Intensity on the Chlorogenic Acid Biosynthesis Pathway in Marsdenia tenacissima

The goal of this study was to understand the effect of light intensity on the chlorogenic acid content and biosynthesis-related gene expression in Marsdenia tenacissima. In this study, M. tenacissima plants were treated with different light intensities; the chlorogenic acid content was determined by high-performance liquid chromatography; and transcriptome sequencing was performed. The amount of chlorogenic acid in the control was the highest and differed significantly from that under three different shading treatments. With a decrease in light intensity, the content of chlorogenic acid also showed a decreasing trend. A total of 1149 differentially expressed genes were identified by transcriptome sequencing, and most of the genes were down-regulated under the 90% shading treatment. A weighted gene co-expression network analysis identified the differentially expressed genes associated with light-induced chlorogenic acid biosynthesis. The different shading treatments down-regulated the expression of the chlorogenic acid biosynthesis pathway structural genes (HCTs). The MIKC family genes were the main transcription factors regulating light-induced chlorogenic acid biosynthesis, but the MYB and SBP family genes were also involved. In summary, combined physiological and transcriptome analysis, candidate structural genes, and transcription factors in the biosynthesis pathway of chlorogenic acid were identified in M. tenacissima.

Abstract PO4-13-10: The anti-metastatic role of BMP4 through cholesterol biosynthesis inhibition and consequent interaction with statin benefit in breast cancer

Abstract We have previously identified a role for bone morphogenic protein 4 (BMP4) in reducing distant relapse risk after early breast cancer (BrCa) (1). We therefore set out to identify mechanisms underlying the protective effect of BMP4, looking to translate this finding for patient benefit. A highly metastatic variant of the triple negative MDA-MB-231 human BrCa line (231-HM-turboGFP) was transduced with BMP4, leading to sustained BMP4 secretion. These modified tumours were established in NSG mice, resected at a given size and turboGFP-positive cancer cells were recovered from primary tumours for RNA sequencing analysis. Gene set enrichment analysis (GSEA) was completed to identify signalling pathways that were significantly modulated by BMP4. The four most significantly downregulated gene sets were associated with cholesterol synthesis, with the overwhelming majority of genes in this pathway being downregulated. BMP4 downregulation of 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1, involved in cholesterol biosynthesis) was confirmed at the protein level by western blotting on whole tumour lysates. Forced expression of BMP4 also led to a significant reduction in the levels of free and total cholesterol. In a confirmatory analysis of the METABRIC human BrCa dataset, the expression of cholesterol biosynthesis-related genes inversely correlated with the expression of BMP4. Further, for the majority of these genes, expression was elevated in high-grade breast tumours, and predicted worse overall survival of patients. Finally, we tested the effect of a lipophilic statin, lovastatin, on the growth and metastasis of 231-HM-turboGFP tumours. Treatment did not affect the growth of primary tumours but significantly less metastases were observed in the lungs of treated mice, at least partially replicating the anti-metastatic effect of BMP4. Having identified inhibition of cholesterol biosynthesis as a potential mechanism of protective BMP4 action we then asked if BMP4 status interacted with any protective effect of co-administered statins. We therefore returned to the cohort initially employed to demonstrate BMP4 benefit (1) and looked at the interaction between BMP4 protein levels and statin usage with regards to recurrence. BMP4 protein and statin usage data were available on a cohort of 417 patients with early BrCa. Statin use compared to none led to a reduced risk of distant relapse (8 v 22%, 0.0029) at 15 years. BMP4 led to borderline reduction in distant relapse (16 v 24%, p=0.052). In BMP4 negative tumours, statin protected against any relapse (p=0.0025) whereas in BMP4 positive disease no significant risk reduction was not significant (p=0.074). Absence of BMP4 expression may be a biomarker of both higher relapse risk and statin benefit in early BrCa. 1. Eckhardt et al, Cancer Res. 2020;80(6):1304-1315 Citation Format: Lap Hing Chi, Andrew Redfern, Allan Burrows, Suraya Roslan, Leone Oh, Lisa Spalding, Robin Anderson. The anti-metastatic role of BMP4 through cholesterol biosynthesis inhibition and consequent interaction with statin benefit in breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-13-10.

Dietary hydroxyproline supplementation improves the muscle texture and extends the shelf life of abalone Haliotis discus hannai

In the present study, an 84-day growth trial was conducted in abalone Haliotis discus hannai to evaluate the influences of dietary hydroxyproline (Hyp) levels (0.05, 0.53 and 1.24%) on the growth, collagen metabolism, muscle texture and its changes during storage at 4 °C. The results showed that the weight gain rate of abalones in the groups with 0.53% and 1.24% of dietary Hyp were significantly higher than that in the group with 0.05% dietary Hyp. The 0.53% and 1.24% of dietary Hyp significantly increased lysyl hydroxylase and prolyl 4-hydroxylase activity and pyridinium crosslink content, and up-regulated collagen biosynthesis-related gene expression in abalone muscle. Meanwhile, dietary Hyp supplementation significantly inhibited the mRNA expression of mmp-1 and significantly up-regulated the mRNA expression of timp. During the same storage time, the springiness, hardness and water-holding capacity of muscle in the dietary Hyp supplementation treatments were significantly higher. The muscle hardness in the dietary Hyp supplementation groups on day 6 was higher than that in the control group on day 3. Meanwhile, dietary Hyp significantly decreased the content of carbonyl and malonaldehyde, as well as the activity of cathepsin B and cathepsin L in the muscle of abalone during the storage. In conclusion, dietary Hyp supplementation increased collagen content, improved texture and extended the shelf life of abalone.

Comparative physiological, biochemical, metabolomic, and transcriptomic analyses reveal the formation mechanism of heartwood for Acacia melanoxylon

Acacia melanoxylon is well known as a valuable commercial tree species owing to its high-quality heartwood (HW) products. However, the metabolism and regulatory mechanism of heartwood during wood development remain largely unclear. In this study, both microscopic observation and content determination proved that total amount of starches decreased and phenolics and flavonoids increased gradually from sapwood (SW) to HW. We also obtained the metabolite profiles of 10 metabolites related to phenolics and flavonoids during HW formation by metabolomics. Additionally, we collected a comprehensive overview of genes associated with the biosynthesis of sugars, terpenoids, phenolics, and flavonoids using RNA-seq. A total of ninety-one genes related to HW formation were identified. The transcripts related to plant hormones, programmed cell death (PCD), and dehydration were increased in transition zone (TZ) than in SW. The results of RT-PCR showed that the relative expression level of genes and transcription factors was also high in the TZ, regardless of the horizontal or vertical direction of the trunk. Therefore, the HW formation took place in the TZ for A. melanoxylon from molecular level, and potentially connected to plant hormones, PCD, and cell dehydration. Besides, the increased expression of sugar and terpenoid biosynthesis-related genes in TZ further confirmed the close connection between terpenoid biosynthesis and carbohydrate metabolites of A. melanoxylon. Furthermore, the integrated analysis of metabolism data and RNA-seq data showed the key transcription factors (TFs) regulating flavonoids and phenolics accumulation in HW, including negative correlation TFs (WRKY, MYB) and positive correlation TFs (AP2, bZIP, CBF, PB1, and TCP). And, the genes and metabolites from phenylpropanoid and flavonoid metabolism and biosynthesis were up-regulated and largely accumulated in TZ and HW, respectively. The findings of this research provide a basis for comprehending the buildup of metabolites and the molecular regulatory processes of HW formation in A. melanoxylon.

Gα3 regulates growth and development, stress response, patulin synthesis and pathogenicity of Penicillium expansum by mediating cAMP/PKA and PKC signaling

G proteins are signaling proteins in eukaryotes that transduce extracellular signals into the intracellular space. There are three classes of Gα proteins in fungi, among which class III Gα proteins play crucial roles for fungal growth, secondary metabolism, and pathogenicity. In this study, we found that the Gα3 protein from Penicillium expansum belongs to the P-loop NTPase superfamily and contains a G-alpha conserved domain and an adenylate cyclase binding site that can bind to guanine nucleotides. Deletion of Gα3 downregulated the expression of the cAMP/PKA signaling pathway genes AC, PkaC, and PkaR, and the PKC signaling related genes PKC1, PKC2, and PLC of P. expansum. The Gα3-deleted strain showed slow colony growth, irregular depression at the colony edge, and increased branching at the mycelial tip. Gα3 deletion decreased spore production, inhibited spore germination, and reduced the expression levels of genes that regulate conidiospore formation, including abaA, wetA, vosA and brlA. In addition, the Gα3-deleted strain grew faster in carbon and NO3- medium, and was more sensitive to salt and oxidative stress, but less sensitive to cell wall stress. Gα3 deletion significantly downregulated the expression of patulin biosynthesis-related genes except for PatF and PatM, and reduced the patulin levels in vivo and in vitro. In addition, loss of Gα3 reduced the pathogenicity of the strain on fruit, with down-regulated expression of the extracellular enzyme genes PG, PL, and PLA. In conclusion, Gα3 can regulate growth and development, carbon and nitrogen response, stress response, patulin biosynthesis and pathogenicity by mediating cAMP/PKA and PKC signaling pathways of P. expansum.

Genome-Wide Identification and Expression Analysis of Fifteen Gene Families Involved in Anthocyanin Synthesis in Pear

Anthocyanins play a crucial role in imparting red coloration to pear fruits. However, the specific number and expression patterns of each member within the anthocyanin biosynthesis-related gene families in pears require systematic exploration. In this study, based on the pear genome we identified 15 gene families involved in the anthocyanin biosynthesis pathway using the BLASTP and Hidden Markov Model search methods, comprising a total of 94 enzyme genes. Through phylogenetic analysis, conserved domains, motif, and gene structure analysis, these gene families were further categorized into eight distinct lineages. Subsequent collinearity analysis revealed that the expansion of anthocyanin synthesis-related gene families primarily originated from segmental duplications. Analysis of cis-element in the promoter regions of genes related to anthocyanin synthesis unveiled the presence of light-responsive elements and various hormone-responsive elements. This suggests that changes in light stimulation and hormone levels may influence anthocyanin synthesis. RNA-Seq and qRT-PCR analyses indicated differential expression of anthocyanin biosynthesis-related genes between the peel and flesh tissues. During the accumulation of anthocyanins in red-fleshed pears, upstream genes in the anthocyanin biosynthesis pathway such as PbrPAL2, PbrC4H2, PbrC4H3, Pbr4CL2, Pbr4CL17, PbrF3H5, and PbrF3H6 exhibited high expression levels, likely contributing significantly to the red coloration of pear flesh. In summary, we have identified the number of gene family members involved in pear anthocyanin biosynthesis and analyzed the expression patterns of the genes related to pear anthocyanin biosynthesis. These findings provide a solid foundation for further research on the regulatory mechanisms underlying pear anthocyanin biosynthesis and the breeding of red pear varieties.

Tobacco Transcription Factor NtWRKY70b Facilitates Leaf Senescence via Inducing ROS Accumulation and Impairing Hydrogen Sulfide Biosynthesis.

Leaf senescence is the terminal stage of leaf development, and its initiation and progression are closely controlled by the integration of a myriad of endogenous signals and environmental stimuli. It has been documented that WRKY transcription factors (TFs) play essential roles in regulating leaf senescence, yet the molecular mechanism of WRKY-mediated leaf senescence still lacks detailed elucidation in crop plants. In this study, we cloned and identified a tobacco WRKY TF gene, designated NtWRKY70b, acting as a positive regulator of natural leaf senescence. The expression profile analysis showed that NtWRKY70b transcript levels were induced by aging and hydrogen peroxide (H2O2) and downregulated upon hydrogen sulfide (H2S) treatment. The physiological and biochemical assays revealed that overexpression of NtWRKY70b (OE) clearly promoted leaf senescence, triggering increased levels of reactive oxygen species (ROS) and decreased H2S content, while disruption of NtWRKY70b by chimeric repressor silencing technology (SRDX) significantly delayed the onset of leaf senescence, leading to a decreased accumulation of ROS and elevated concentration of H2S. The quantitative real-time PCR analysis showed that the expression levels of various senescence-associated genes and ROS biosynthesis-related genes (NtRbohD and NtRbohE) were upregulated in OE lines, while the expression of H2S biosynthesis-related genes (NtDCD and NtCYSC1) were inhibited in OE lines. Furthermore, the Yeast one-hybrid analysis (Y1H) and dual luciferase assays showed that NtWRKY70b could directly upregulate the expression of an ROS biosynthesis-related gene (NtRbohD) and a chlorophyll degradation-related gene (NtPPH) by binding to their promoter sequences. Accordingly, these results indicated that NtWYKY70b directly activated the transcript levels of NtRbohD and NtPPH and repressed the expression of NtDCD and NtCYCS1, thereby promoting ROS accumulation and impairing the endogenous H2S production, and subsequently accelerating leaf aging. These observations improve our knowledge of the regulatory mechanisms of WRKY TFs controlling leaf senescence and provide a novel method for ensuring high agricultural crop productivity via genetic manipulation of leaf senescence in crops.

Exploring the Production of Secondary Metabolites from a Halophyte Tetragonia tetragonoides through Callus Culture

Considering Korea’s gradual shift toward an aging society, consumer interest in compounds with physiological benefits, including antioxidant and anticancer effects, has surged. This study explored the potential of Tetragonia tetragonoides (Pall.) Kunze, commonly known as New Zealand Spinach (NZS), a halophyte with reported health benefits, including efficacy in treating gastrointestinal diseases, high blood pressure, diabetes, and obesity. This study also introduced a novel callus culture system for NZS, allowing for the rapid in vitro production of secondary metabolites. Optimal callus induction (100%) and biomass production (0.416 g) were achieved by adding 2.0 mg·L−1 6-BA (6-Benzylaminopurine) and 0.5 mg·L−1 2,4-D (2,4-Dichlorophenoxyacetic acid) among five auxin and cytokinin combinations. Two distinct callus types, TGC [TDZ (Thidiazuron)-supplemented Green Callus] and TNYC [TDZ + NAA (Naphthalene acetic acid)-supplemented Yellow Callus], were identified, each with unique characteristics. The calli showed total phenolic and flavonoid contents comparable to those of NZS leaves grown in the greenhouse. An expression analysis of six genes (CHS, CHI, F3H, F3′H, FLS, and DFR) involved in the kaempferol biosynthesis revealed an enhanced flavonoid biosynthesis-related gene expression in TGC, emphasizing its potential for compound production. GC-MS analysis identified distinct compound profiles in TGC and TNYC, with 2,3-butanediol and succinic acid being the predominant compounds among the nine and forty-four components, respectively. These calli offer a stable supply of functional compounds and present an environmentally sustainable solution. The derived callus culture system is anticipated to contribute to the development of healthy functional foods or pharmaceuticals from halophyte NZS.

GhAGL16 (AGAMOUS-LIKE16) Negatively Regulates Tolerance to Water Deficit in Transgenic Arabidopsis and Cotton.

Cotton is one of the most economically important crops in the world, and drought is a key abiotic factor that can significantly reduce cotton yield. MADS-box transcription factors play essential roles in various aspects of plant growth and development as well as responses to biotic and abiotic stress. However, the use of MADS-box transcription factors to regulate water stress responses has not been fully explored in cotton. Here, we showed that GhAGL16 acts as a negative regulator of water deficit in cotton, at least in part by regulating ABA signaling. GhAGL16-overexpressing (GhAGL16-OE) transgenic Arabidopsis had lower survival rates and relative water contents (RWCs) under water stress. Isolated leaves of GhAGL16-OE Arabidopsis had increased water loss rates, likely attributable to their increased stomatal density. GhAGL16-OE Arabidopsis also showed reduced primary root lengths in response to mannitol treatment and decreased sensitivity of seed germination to ABA treatment. By contrast, silencing GhAGL16 in cotton enhanced tolerance to water deficit by increasing proline (Pro) content, increasing superoxide dismutase (SOD) and peroxidase (POD) activities, and reducing malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents under water stress. Subcellular localization and transcriptional activation assays confirmed that GhAGL16 is a nuclear protein that lacks transcriptional self-activation activity. The expression of ABA biosynthesis-related genes (GhNCED3/7/14), a catabolism-related gene (GhCYP707A), and a gene related to the ABA signaling pathway (GhABF4) was altered in GhAGL16-silenced plants. Taken together, our data demonstrate that GhAGL16 plays an important role in cotton resistance to water stress.

Ti3C2Tx MXene nanosheets protect Torreya grandis against root rot disease

Root rot is a soil-borne disease primarily caused by fungi. The malady not only decrease the ability of absorbing water and nutrients, but also severely threat agricultural productivity. Recently, a new family member of two-dimensional (2D) transition metal carbide materials, MXene (Ti3C2Tx), has gained much interest as a promising approach to control fungi. However, the efficient use and mechanism of MXene in protecting plant against pathogenic fungus are still rarely reported. Here, the synthesized MXene were first characterized by the atomic force microscopy (AFM), scanning electron microscopy (SEM), dynamic light scattering (DLS), transmission electron microscopy (TEM) and X-ray photoelectron spectra (XPS). MXene application in soil obviously enhanced the root rot disease resistance of T. grandis. Soil microbial community analysis indicated that the abundance of Fusasium genus was decreased by 68.32% after MXene treatment. Further, MXene specially affected the permeability of Fusarium solani via damaging their cell membranes, thereby causing the disintegration and cell death of F. solani. In addition, MXene nanoflakes could transport into roots through T. grandis root air space, which resulted in the accumulation of lignin in roots via enhancing the expression and activities of lignin biosynthesis-related genes in T. grandis roots. Taken together, our finding pioneers comprehensive insights into the antifungal mechanism of MXene against F. solani and the efficiency use of MXene in protecting plant against pathogenic fungus, which will prompt the rapid development of nanotechnology in sustainable forestry.

The Electrical Conductivity of Nutrient Solution Influenced the Growth, Centellosides Content and Gene Expression of Centella asiatica in a Hydroponic System

Centella asiatica is a herbaceous plant containing medicinal and cosmetic properties: anti-bacterial, anti-aging, memory enhancing and wound healing. The lack of information impedes the development of suitable growth conditions for C. asiatica in the hydroponic system. Maintaining proper electrical conductivity (EC) of a nutrient solution is considered crucial for plant growth and the accumulation of bioactive compounds in a plant grown in hydroponics. This study aimed to investigate an optimal EC that enhances the growth of C. asiatica and its centellosides content. Seedlings were grown in commercial nutrient solution and treated with four different strengths of EC (0.6, 1.2, 1.8 and 2.4 indicated T1, T2, T3 and T4, respectively) under controlled environment conditions. Our results demonstrate that the number of leaves, leaf area, number of runners, shoot fresh weight and shoot dry weight were significantly increased in T2 among the treatments. However, these growth parameters were lowest in T4. Furthermore, the content of asiaticoside, madecassoside, asiatic acid and madecassic acid was the highest in plants that were treated with T2. The expression of centelloside biosynthesis-related genes is also affected by the strength of the nutrient solution. A positive correlation was observed between the number of leaves, leaf area and centellosides content. This study provides valuable background on optimal EC content in the nutrient solution in a hydroponic system with enhanced centellosides content to leverage the C. asiatica production.

GhL1L1 regulates the contents of unsaturated fatty acids by activating the expression of GhFAD2 genes in cotton

Edible oils with high unsaturated fatty acids, particularly oleic acid, are beneficial to human health. Cotton is one of the top five oil crops in the world, but the mechanism of high-quality oil synthesis and regulatory networks in cotton are largely unclear. Here, we identified Leafy cotyledon1-like 1 (GhL1L1), a NF-YB subfamily gene that is specifically expressed during somatic embryogenesis and seed maturation in cotton. Overexpression of GhL1L1 regulates the contents of unsaturated fatty acids in cotton, especially in the seeds, which is associated with altered expression of the cotton fatty acid biosynthesis-related genes. GhL1L1 synergistically enhanced the expression of GhFAD2-1A by binding to the G-box in its promoter, leading to an increase in the content of linoleic acid. Furthermore, this activation could be enhanced by GhNF-YC2 and GhNF-YA1 by form a transcriptional complex. Collectively, these results contribute to provide new insights into the molecular mechanism of oil biosynthesis in cotton and can facilitate genetic manipulation of cotton varieties with enhanced oil content.

Polymethoxyflavone (PMF) Accumulation and PMF Biosynthesis-Related Gene Expression in Tachibana (Citrus tachibana Tanaka) Fruit Treated Using a Combination of Gibberellic Acid and Prohydrojasmon and Post-harvest Deep-Ultraviolet Light-Emitting Diode Irradiation

Polymethoxyflavone (PMF) Accumulation and PMF Biosynthesis-Related Gene Expression in Tachibana (Citrus tachibana Tanaka) Fruit Treated Using a Combination of Gibberellic Acid and Prohydrojasmon and Post-harvest Deep-Ultraviolet Light-Emitting Diode Irradiation

Differential Coloration, Pigment Biosynthesis-Related Gene Expression, and Accumulation According to Developmental Stage in the ‘Enbu’ Apple

Coloration, a major factor contributing to apple quality, attracts consumer attraction, thereby increasing the sale of fruits in the market. Among the fruit pigments, anthocyanins and carotenoids are the most important pigments that impart coloration to apples. Pigment accumulation, which is regulated by transcriptional factors in the anthocyanin and carotenoid biosynthesis pathways, varies according to genetics, transcription, and developmental stage. To understand the regulation of color development in apples, we evaluated the expression of the genes in the anthocyanin and carotenoid biosynthetic pathways and analyzed the accumulation of pigment, including anthocyanin and carotenoid in the skin and flesh of the red-fleshed apple ‘Enbu’ cultivar at different fruit development stages (30, 60, 90, 120, and 150 days after full bloom, and ripe). Color development increased according to the developmental stage, with considerable variation in both the transcript levels and pigment concentrations observed in tissues, skin, and flesh. Moreover, we identified key transcription factors among the anthocyanin and carotenoid biosynthesis genes that regulated pigment accumulation. Pearson’s correlation analysis showed a strong correlation between the coloration patterns and the expression levels of anthocyanin biosynthesis-related genes (MdPAL, MdCHI, and MdF3H) and carotenoid biosynthesis-related genes (MdGGPPS, MdPSY, MdZDS, MdCRTISO, MdCRHβ, and MdZEP). This study provides insight into the molecular mechanisms underlying pigment biosynthesis for breeding high-quality red-fleshed apple varieties to cater to consumer attention and preference.

Ectopic expression of SpABR1 positively regulates drought stress tolerance through the ABA-dependent pathway and by promoting ROS scavenging in Arabidopsis

Glucosyltransferases, Rab-like GTPase activators and Myotubularins (GRAM) domain-containing proteins are essential for plant growth and reactions to abiotic stresses. The desert shrub willow Salix psammophila C. is native to arid and semi-arid areas and has strong tolerance of abiotic stresses. We previously identified a GRAM domain-containing protein, SpABR1, as a hub gene in the response of S. psammophila to drought stress. In this study, SpABR1 was isolated and functionally characterized. Analysis of expression patterns revealed highest SpABR1 expression in the roots. Additionally, GUS staining revealed the upregulation of SpABR1 in response to drought stress and ABA treatment. Overexpression of SpABR1 resulted in enhanced tolerance to drought stress and heightened ABA sensitivity. Compared to wild-type (WT) plants, plants with overexpressed SpABR1 exhibited increased activities of antioxidant enzymes under drought stress. In SpABR1 overexpression plants, there was higher expression of stress-related genes and ABA biosynthesis-related genes compared to WT plants under drought stress conditions. Additionally, results from a yeast one-hybrid screening assay and luciferase analysis revealed that SpNAC2 is an up-regulated gene that directly interacts with the promoter region of SpABR1 to activate its expression. Our findings revealed a positive role of SpABR1 in drought stress and provided insight into its regulatory network.

The Synergistic Effects of Environmental and Genetic Factors on the Regulation of Anthocyanin Accumulation in Plant Tissues.

Anthocyanin accumulation is responsible for the coloration of apple fruit, and their accumulation depends on the expression of anthocyanin biosynthesis-related genes. Light is an environmental stimulus that induces fruit color by regulating genes involved in the anthocyanin biosynthesis pathway. In this study, the roles of light and genetic factors on fruit coloration and anthocyanin accumulation in apple fruit were investigated. Three genes in the anthocyanin biosynthesis pathway, MdCHS, MdANS, and MdUFGT1, were synthesized and cloned into a viral-based expression vector system for transient expression in 'Ruby S' apple fruits. Apple fruits were agroinfiltrated with expression vectors harboring MdCHS, MdANS, and MdUFGT1. Agroinfiltrated apple fruits were then either kept in the dark (bagged fruits) or exposed to light (exposed fruits). The agroinfiltrated fruits showed significantly different coloration patterns, transcript expression levels, and anthocyanin accumulation compared to the control fruits. Moreover, these parameters were higher in exposed fruits than in bagged fruits. For stable expression, MdCHS was introduced into a binary vector under the control of the rice α-amylase 3D (RAmy3D) promoter. The ectopic overexpression of MdCHS in transgenic rice calli showed a high accumulation of anthocyanin content. Taken together, our findings suggest that light, together with the overexpression of anthocyanin biosynthesis genes, induced the coloration and accumulation of anthocyanin content in apple fruits by upregulating the expression of the genes involved in the anthocyanin biosynthesis pathway.

Alkane biosynthesis is promoted in methyl jasmonate-treated sweet cherry (Prunus avium) fruit cuticles.

The cuticle plays an important role in the survival of plants, and it is important to preserve the quality of fleshy fruits like sweet cherry. Plant hormones play a role in cuticle formation. In this sense, jasmonates have been shown to induce cuticle biosynthesis, but until today this has not been demonstrated in sweet cherry fruit. Therefore, the effect of exogenous methyl jasmonate (MeJA) application at the fruit set stage on the expression levels of cuticle synthesis-related genes and the wax composition of the isolated cuticle was studied in developing and ripe fruits of sweet cherry (Prunus avium 'Bing'), respectively. MeJA treatment resulted in up-regulation of the cuticle biosynthesis-related gene expression, such as PaWINA, PaWINB, PaKCS1, PaKCS6, PaLACS1, PaLACS2, PaWS, and PaWBC11. These genes play a vital role in the elongation and transport of fatty acids, and wax biosynthesis. Analysis of cuticular components in ripe fruit showed an increase in long-chain linear aliphatic wax compounds, particularly C27, C28, C29, C30, and C31 alkanes. Exogenous MeJA application at the fruit set stage of sweet cherry has a significant effect on the wax composition of the ripe fruit cuticle, particularly in terms of alkane biosynthesis. The results of this study may provide insights into the regulation of cuticle biosynthesis by jasmonates and be useful for improving fruit quality and storage life. © 2023 Society of Chemical Industry.

Jasmonic acid regulates lignin deposition in poplar through JAZ5-MYB/NAC interaction.

Jasmonic acid (JA) is a phytohormone involved in plant defense, growth, and development, etc. However, the regulatory mechanisms underlying JA-mediated lignin deposition and secondary cell wall (SCW) formation remain poorly understood. In this study, we found that JA can inhibit lignin deposition and SCW thickening in poplar trees through exogenous MeJA treatment and observation of the phenotypes of a JA synthesis mutant, opdat1. Hence, we identified a JA signal inhibitor PtoJAZ5, belonging to the TIFY gene family, which is involved in the regulation of secondary vascular development of Populus tomentosa. RT-qPCR and GUS staining revealed that PtoJAZ5 was highly expressed in poplar stems, particularly in developing xylem. Overexpression of PtoJAZ5 inhibited SCW thickening and down-regulated the expression of SCW biosynthesis-related genes. Further biochemical analysis showed that PtoJAZ5 interacted with multiple SCW switches NAC/MYB transcription factors, including MYB3 and WND6A, through yeast two-hybrid and bimolecular fluorescent complementation experiments. Transcriptional activation assays demonstrated that MYB3-PtoJAZ5 and WND6A-PtoJAZ5 complexes regulated the expression of lignin synthetic genes. Our results suggest that PtoJAZ5 plays a negative role in JA-induced lignin deposition and SCW thickening in poplar and provide new insights into the molecular mechanisms underlying JA-mediated regulation of SCW formation.

Integrated lipidomic and transcriptomic analyses reveal the mechanism of lipid biosynthesis and accumulation during seed development in sesame.

Sesame is one of the most important oilseed crops and attracts significant attention because of its huge nutritional capacity. However, the molecular mechanisms underlying oil accumulation in sesame remains poorly understood. In this study, lipidomic and transcriptomic analyses in different stages of sesame seed (Luzhi No.1, seed oil content 56%) development were performed to gain insight into the regulatory mechanisms that govern differences in lipid composition, content, biosynthesis, and transport. In total, 481 lipids, including fatty acids (FAs, 38 species), triacylglycerol (TAG, 127 species), ceramide (33 species), phosphatidic acid (20 species), and diacylglycerol (17 species), were detected in developing sesame seed using gas and liquid chromatography-mass spectrometry. Most FAs and other lipids accumulated 21-33 days after flowering. RNA-sequence profiling in developing seed highlighted the enhanced expression of genes involved in the biosynthesis and transport of FAs, TAGs, and membrane lipids, which was similar to that seen during lipid accumulation. Through the differential expression analysis of genes involved in lipid biosynthesis and metabolism during seed development, several candidate genes were found to affect the oil content and FA composition of sesame seed, including ACCase, FAD2, DGAT, G3PDH, PEPCase, WRI1 and WRI1-like genes. Our study reveals the patterns of lipid accumulation and biosynthesis-related gene expression and lays an important foundation for the further exploration of sesame seed lipid biosynthesis and accumulation.