Phenylpropanoid Research Articles

Silicon-mediated resilience: Unveiling the protective role against combined cypermethrin and hymexazol phytotoxicity in tomato seedlings

Insecticides and fungicides present potential threats to non-target crops, yet our comprehension of their combined phytotoxicity to plants is limited. Silicon (Si) has been acknowledged for its ability to induce crop tolerance to xenobiotic stresses. However, the specific role of Si in alleviating the cypermethrin (CYP) and hymexazol (HML) combined stress has not been thoroughly explored. This study aims to assess the effectiveness of Si in alleviating phytotoxic effects and elucidating the associated mechanisms of CYP and/or HML in tomato seedlings. The findings demonstrated that, compared to exposure to CYP or HML alone, the simultaneous exposure of CYP and HML significantly impeded seedling growth, resulting in more pronounced phytotoxic effects in tomato seedlings. Additionally, CYP and/or HML exposures diminished the content of photosynthetic pigments and induced oxidative stress in tomato seedlings. Pesticide exposure heightened the activity of both antioxidant and detoxification enzymes, increased proline and phenolic accumulation, and reduced thiols and ascorbate content in tomato seedlings. Applying Si (1 mM) to CYP- and/or HML-stressed seedlings alleviated pigment inhibition and oxidative damage by enhancing the activity of the pesticide metabolism system and secondary metabolism enzymes. Furthermore, Si stimulated the phenylpropanoid pathway by boosting phenylalanine ammonia-lyase activity, as confirmed by the increased total phenolic content. Interestingly, the application of Si enhanced the thiols profile, emphasizing its crucial role in pesticide detoxification in plants. In conclusion, these results suggest that externally applying Si significantly alleviates the physio-biochemical level in tomato seedlings exposed to a combination of pesticides, introducing innovative strategies for fostering a sustainable agroecosystem.

Sodium silicate accelerates suberin accumulation at wounds of potato tuber by inducing phenylpropanoid pathway and fatty acid metabolism during healing

Although soluble silicate was reported to accelerate wound healing in muskmelon fruit through encouraging the deposition of lignin or free fatty acids, whether sodium silicate affects the biosynthesis, cross-linking and transport of suberin monomers during potato wound healing remains unknown. In this study, sodium silicate upregulated the expression and activity of 4-coumarate: coenzyme A ligase (4CL), phenylalanine ammonia lyase (PAL), and promoted the synthesis of phenolic acids (caffeic acid, p-coumaric acid, cinnamic acid, sinapic acid, and ferulic acid) in tuber wounds. Meanwhile, sodium silicate upregulated the expression of glycerol-3-phosphate acyltransferase (StGPAT), fatty acyl reductase (StFAR), long-chain acyl-CoA synthetase (StLACS), β-ketoacyl-CoA synthase (StKCS), and cytochrome P450 (StCYP86A33), and thus increased the levels of α, ω-diacids, ω-hydroxy acids, and primary alcohols in wounds. Sodium silicate also induced the expression of ω-hydroxy acid/fatty alcohol hydroxycinnamoyl transferase (StFHT), ABC transporter (StABCG), and promoted the deposition of suberin in wound surface, hence reducing tuber disease index and weight loss during healing. Taken together, sodium silicate may accelerate suberin accumulation at potato tubers wound through inducing the phenylpropanoid pathway and fatty acid metabolism.

A 3R-MYB transcription factor is involved in Methyl Jasmonate-Induced disease resistance in Agaricus bisporus and has implications for disease resistance in Arabidopsis

IntroductionMethyl jasmonate (MeJA) and MYB transcription factors (TFs) play important roles in pathogen resistance in several plants, but MYB TFs in conjunction with MeJA-induced defense against Pseudomonas tolaasii in edible mushrooms remain unknown. ObjectivesTo investigate the role of a novel 3R-MYB transcription factor (AbMYB11) in MeJA-induced disease resistance of Agaricus bisporus and in the resistance of transgenic Arabidopsis to P. tolaasii. MethodsMushrooms were treated with MeJA alone or in combination with phenylpropanoid pathway inhibitors, and the effects of the treatments on the disease-related and physiological indicators of the mushrooms were determined to assess the role of MeJA in inducing resistance and the importance of the phenylpropanoid pathway involved. Subcellular localization, gene expression analysis, dual-luciferase reporter assay, electrophoretic mobility shift assay, and transgenic Arabidopsis experiments were performed to elucidate the molecular mechanism of AbMYB11 in regulating disease resistance. ResultsMeJA application greatly improved mushroom resistance to P. tolaasii infection, and suppression of the phenylpropanoid pathway significantly weakened this effect. MeJA treatment stimulated the accumulation of phenylpropanoid metabolites, which was accompanied by increased the activities of biosynthetic enzymes and the expression of phenylpropanoid pathway-related genes (AbPAL1, Ab4CL1, AbC4H1) and an AbPR-like gene, further confirming the critical role of the phenylpropanoid pathway in MeJA-induced responses to P. tolaasii. Importantly, AbMYB11, localized in the nucleus, was rapidly induced by MeJA treatment under P. tolaasii infection; it transcriptionally activated the phenylpropanoid pathway-related and AbPR-like genes, and AbMYB11 overexpression in Arabidopsis significantly increased the transcription of phenylpropanoid-related genes, the accumulation of total phenolics and flavonoids, and improved resistance to P. tolaasii. ConclusionThis study clarified the pivotal role of AbMYB11 as a regulator in disease resistance by modulating the phenylpropanoid pathway, providing a novel idea for the breeding of highly disease-resistant edible mushrooms and plants.

Transcriptomics and metabolomics revealed the molecular basis of the color formation in the roots of Panax notoginseng

Panax notoginseng is a traditional Chinese medicine rich in many pharmacological components. The root of the ‘Miaoxiang Sanqi No. 2’ is yellow or greenish yellow, while a novel cultivar-‘Wenyuan Ziqi No. 1’ shows purple root and is thought to have high medicinal value. Little information is available about the anthocyanin biosynthesis in P. notoginseng root. In this study, we compared the ‘Miaoxiang Sanqi No. 2’ and ‘Wenyuan Ziqi No. 1’ in morphological, transcriptional and metabolic levels. The results showed that purple rich in the periderm, rhizome and phloem around cambium of the ‘Wenyuan Ziqi No. 1’ root and cyanidin 3-O-galactoside was the main anthocyanin causing purple. Moreover, ‘Wenyuan Ziqi No. 1’ highly accumulated in 155 metabolites, including flavones, phenylpropanoids and lipids. Transcriptome data showed that phenylpropanoid biosynthesis pathway genes are highly expressed in ‘Wenyuan Ziqi No. 1’. Conjoint analysis showed that anthocyanin biosynthesis pathway substances were highly accumulated in ‘Wenyuan Ziqi No. 1’, and the expression level of structural genes involved in anthocyanin biosynthesis pathway was higher in ‘Wenyuan Ziqi No. 1’. Meanwhile, eight R2R3-MYB genes that might be involved in anthocyanin biosynthesis were identified. The comprehensive analysis of two cultivars provides new insights into the understanding of root coloration in P. notoginseng.

Transcriptome and Metabolomic Analyses Reveal Tissue-Specific Glycosylation of Phenylpropanoids and Flavonoids in Toxicodendron vernicifluum.

Toxicodendron vernicifluum (Stokes) F. A. Barkley is a tree species used primarily for lacquer production. Our study utilized transcriptome and metabolomic analysis to investigate the biosynthesis of phenylpropanoids and flavonoids, specifically the glycosylated forms, in T. vernicifluum roots, stems, and leaves. HPLC-QTOF-MS/MS identified 186 compounds, with tissue-specific distributions revealed by PCA. Flavonoids and phenylpropanoids glycosides were significantly more abundant in leaves compared with roots and stems. Full-length sequencing uncovered 17,266 transcripts in T. vernicifluum. Gene expression analysis showed higher activity of phenylpropanoid and flavonoid biosynthesis pathways in leaves. Certain genes, such as CYP73A, 4CL, CRR, CYP84A/F5H, and CYP93C, displayed associations with compound content distributions. Root tissue exhibited a higher concentration of isoflavones. Notably, glycosyltransferase expression demonstrated significant correlations with glycosylated compounds' content. Biochemical validation confirmed the involvement of TvPB_c0_g2904, encoding a UDP-glucosyltransferase, in genistin biosynthesis in T. vernicifluum.

Deciphering the behind blackspot exocarp disorder in avocado cv. Hass through a hormonal, transcriptional and metabolic integration approach

Avocado cv. Hass is an important sub-tropical crop with an increasing global demand. However, the avocado supply chain experiences significant fruit losses, particularly during the postharvest stage due to diseases and disorders that manifest after prolonged cold storage or the ready-to-eat stage. The blackspot exocarp disorder, which appears as brown or black blotches only after extended cold storage conditions, leads to substantial commercial losses for exported avocados. This research aimed to identify transcriptomic, metabolomic, and hormonal changes in avocado fruits affected by blackspot disorder, differentiating between the green and black exocarp tissues directly impacted by this physiological disorder. The results showed a correlation between the black-colored exocarp of blackspot affected fruits with high levels of gibberellins, cytokinins, jasmonic acid and salicylic acid hormones. Metabolically, these changes were accompanied by a high fatty acid content of oleate, palmitate and linoleate. Using a metabolic pathway reconstruction analysis, we integrated hormonal and metabolic data with transcriptomic information. This approach identified several genes involved in central carbon metabolism, long-chain fatty acid elongation, and jasmonate/salicylate biosynthesis pathways, as well as a possible accumulation of lignins due to a high expression of genes associated with the phenylpropanoid pathway in the black exocarp of blackspot-affected fruits. These findings suggest that blackspot disorder results from a combination of plant defense mechanisms triggered to strengthen the fruit exocarp tissue.

Nitrogen deficiency differentially affects lignin biosynthesis genes and flavanols accumulation in tolerant and susceptible tea genotypes (Camellia sinensis (L.) Kuntze)

The mechanisms of the nitrogen deficiency (ND) response are complex and not sufficiently studied in evergreen tree crops. The aim of this study was to investigate the nitrogen deficiency response in two contrasting tea genotypes to reveal molecular crosstalk between tea quality and tolerance to ND. The transcriptional response to two- and four-month nitrogen deficiency was analyzed in tolerant (cv. Karatum) and susceptible (cv. Kolkhida) tea genotypes. Both GO and KEGG analyses indicated that phenylpropanoid pathway was significantly enriched under nitrogen deficiency in both cultivars. Most of the transcription factor DEGs were related to ABA-mediated stress responses; the following transcription factors were upregulated in both genotypes and in both stress periods: TEAK026346 (bZip23), TEAK015869 (RADIALIS-like 3 isoform X1), TEAK022547 (bHLH78) and one was downregulated TEAK030189 (MYB family transcription factor EFM like) indicating their important role for regulation of nitrogen deficiency response. Gene network of phenylpropanoid pathway DEGs indicated the abandoned edges in lignin biosynthesis DEGs. Generally, the results suggest greater stability of the cell wall metabolism and secondary metabolism in tolerant genotype under long term nitrogen deficiency. The revealed lignin biosynthesis genes can be new candidates for molecular breeding to develop tolerant tea genotypes.

Preharvest methyl jasmonate application delays cell wall degradation and upregulates phenolic metabolism and antioxidant activities in cold stored raspberries

The effects of preharvest methyl jasmonate (MeJA) spray application on the physicochemical quality, metabolism of phenolics, and cell wall components in raspberries were investigated during a 10-day cold storage period. MeJA spray reduced firmness loss, decay incidence, and weight loss, while maintained higher levels of soluble solids content, ascorbic acid, anthocyanins and flavonoids in raspberries. Furthermore, MeJA application resulted in increased total pectin and protopectin levels, as well as lowered water-soluble pectin, and activities of pectin methyl esterase, polygalacturonase and cellulase enzymes. Additionally, MeJA treatment upregulated the phenylpropanoid pathway, leading to higher endogenous phenolics and activities of phenylalanine-ammonia lyase and shikimate dehydrogenase. In conclusion, preharvest MeJA spray application could be adopted to enhance the storage potential of cold-stored raspberries for 10 days by maintaining higher firmness, assuring better physicochemical quality, and increasing phenolic metabolism, while reducing cell wall hydrolysis.

Metagenomic and transcriptome insights into the disease resistance mechanisms in fresh-cut apple under pyridoxine treatment

Microbial spoilage poses a significant challenge to fresh-cut apples during storage, impacting quality and consumer health. This study explores pyridoxine’s (vitamin B6; VB6) potential mode of action to mitigate microbial spoilage in fresh-cut apples through physiological, transcriptomic, and metagenomic analysis. VB6 notably reduces microbial spoilage at room temperature by suppressing bacterial genera (Pseudomonas, Curtobacterium, Frigoribacterium) and fungal genera (Alternaria, Penicillium, Aureobasidium, Pseudogymnoascus) proliferation. Spoilage-causing identified biomarkers include species related to Pseudomonas, Curtobacterium, Frigoribacterium, and Penicillium. KEGG analysis suggests correlations of induced disease resistance with tropane alkaloids biosynthesis, plant-pathogen interaction, and phenylpropanoid biosynthesis pathways in fresh-cut apples. Moreover, VB6 treatment enhanced the antioxidant system via maintaining higher total phenolic contents, total flavonoid contents, and ascorbic acid under elevated catalase, superoxide dismutase, and ascorbate peroxidase enzymes activities, induced disease resistance under higher enzymes activities including phenylalanine ammonialyase, chitinase, cinnamate 4-hydroxylase, β-1,3-glucanase, and 4-coumarate: co-enzyme A ligase enzymes activities, maintained elevated VB6 contents, and reduced H2O2 accumulation. Notably, 6 elevated transcription factors involving WRKY, NAC and MYB might regulate disease resistance pathways in fresh-cut apples under VB6 treatment. This research establishes a theoretical and practical foundation for preserving post-processing quality of fresh-cut apples by restraining microbial proliferation through the proposed VB6-induced disease resistance regulatory mechanism.

In-Depth Understanding of Cytoplasmic Male Sterility by Metabolomics in Spring Stem Mustard (Brassica juncea var. tumida Tsen et Lee)

Male sterility (MS) caused by aborted pollen is a vital germplasm resource. In this study, metabolomic, transcriptomic, and proteomic analyses were performed to investigate the molecular regulatory mechanism of cytoplasmic male sterility (CMS) in the flower buds of the male sterile line 09-05A and its maintainer line, 09-05B, of Brassica juncea. Our metabolomic analysis revealed that 41 metabolites involved in pollen development and male fertility formation were differentially accumulated between 09-05A and 09-05B at the bi-nucleate stage of B. juncea. Integrated omics indicated that the expression of key genes and proteins in the amino acid and phenylpropanoid metabolic pathways was remarkably downregulated in the flower buds of 09-05A. Furthermore, the abnormal expression of key transcription factor (TF) genes related to tapetum development and pollen wall formation may affect pollen development in the 09-05A CMS line. The results indicated that the downregulated expression level of critical genes and proteins in amino acid metabolism; phenylpropanoid synthesis; and TF genes, such as shikimate kinase, phenylalanine ammonia-lyase, and MYB103, may have led to impaired tapetum and pollen wall development, thereby causing pollen abortion in 09-05A. This study provides new insights into the metabolic and molecular regulatory mechanisms underlying the formation of CMS in B. juncea and lays a foundation for detailed studies on the identity and characteristics of MS-related genes.

Theanine enhances resistance to Botrytis cinerea in postharvest strawberry fruit via modulating cell-wall and phenylpropanoid metabolisms

Theanine (N-ethyl-γ-glutamine), as a unique non-protein amino acid, plays vital roles in abiotic stress resistance, while its roles in biotic stress resistance are still unclear. Gray mold caused by Botrytis cinerea is a major disease in strawberries. Effects of theanine on the development of gray mold, cell-wall and phenylpropanoid metabolisms in strawberries were investigated in this study. Results showed that 5 mmol L−1 theanine treatment reduced disease incidence and severity of gray mold in strawberries with antifungal activity in vitro. Meanwhile, theanine treatment enhanced the accumulation of phenolic compounds and lignin, especially ellagic acid, cyanidin, and quercetin, which was associated with increased phenylpropanoid pathway related enzyme activities. Moreover, theanine induced callose deposition and suppressed cell- wall disassembling enzymes, accompanied by higher levels of water insoluble pectin, hemicellulose and cellulose. Therefore, theanine treatment could alleviate decay of B. cinerea-inoculated strawberries by regulating phenylpropanoid and cell-wall metabolisms, maintaining higher levels of phenolic compounds and cell-wall components, thereby contributing to disease resistance and cell-wall structure integrity.

Exposure to toxic cadmium concentration induce physiological and molecular mechanisms alleviating herbivory infestation in Wedelia

Cadmium (Cd) toxicity induces significant disruptions in growth and development, plants have developed strategies to alleviate metal toxicity promoting establishment even during herbivores infestation. The study demonstrates that W. trilobata maintains growth and development under the combined stress of Cd exposure and herbivore invasion by Spodoptera litura, in contrast to W. chinensis. Cd toxicity markedly reduce shoot elongation and total fresh biomass, and a significant decrease in the dry weight of the shoot biomass and leaf count by 19%, 18%, 16%, and 19% in W. trilobata compared to controls. An even more pronounced decrease of 35%, 43%, 45% and 43% was found in W. chinensis. Compared to W. chinensis, W. trilobata showed a higher increase in phytohormone production including abscisic acid (ABA), gibberellic acid (GA3), indole-3-acetic acid (IAA) and methyl jasmonic acid (JA-me) under both Cd and herbivory stress as compared with respective controls. In addition, leaf ultra-structure also showed the highest damage to cell membranous structures by Cd-toxicity in W. chinensis. Furthermore, RNA-seq analysis revealed numerous genes viz., EMSY, MCCA, TIRI, BED-type, ABA, JAZ, CAB-6, CPSI, LHCII, CAX, HNM, ABC-Cd-trans and GBLP being differentially expressed between Cd-stress and herbivory groups in both W. trilobata and W. chinensis, with a particular emphasis on genes associated with metal transport and carbohydrate metabolism. Analyses employing the Gene Ontology (GO) system, the Clusters of Orthologous Groups (COG) categorization, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, highlight the functional and evolutionary relationships among the genes of the Phenylpropanoid and Flavonoid biosynthesis pathways and brassinosterod metabolism, associated with plant growth and development under Cd-toxicity and herbivory. W. trilobata opposite of W. chinensis, significantly improve plant growth and mitigates Cd toxicity through modulation of metabolic processes, and regulation of responsible genes, to sustain its growth under Cd and herbivory stress, which can be used in stress improvement in plants for sustainable ecosystem biodiversity and food security.

Transcriptome analysis of potassium-mediated cadmium accumulation in sweet sorghum

Cadmium (Cd) pollution in the soil is a serious environmental issue worldwide. Phytoextraction of Cd-polluted soil is a cost-effective, sustainable and environmentally-friendly strategy. Agricultural fertilizer management is beneficial for promoting the Cd phytoremediation efficiency. Potassium (K) is the nutrient required in the largest amount cation by plants. Sweet sorghum exhibits a substantial phytoremediation potential of Cd-polluted soil. Clarifying the mechanism of K-mediated Cd accumulation in sweet sorghum is imperative. Sweet sorghum plants were grown hydroponically with an extra K supply in the presence or absence of Cd treatment. An extra K application significantly increased plant growth under non-Cd addition, while K lost the profitable effect under Cd stress. K supplementation remarkably enhanced Cd concentrations and Cd accumulation in shoots and roots of sweet sorghum. Transcriptome analysis demonstrated that zinc ion transport, cysteine and methionine metabolism, flavonoid biosynthesis and phenylpropanoid biosynthesis pathways might contribute to the increased Cd accumulation as affected by an extra K supply. Furthermore, SbZIP9, SbSTP8, SbYS1, SbMAG and SbFOMT-like were targeted as they closely correlated with both plant growth and Cd stress in sweet sorghum. SbFOMT-like showed an independent pathway, while SbZIP9, SbSTP8, SbYS1 and SbMAG displayed positive correlations mutually. Notably, SbZIP9 and SbFOMT-like were highly expressed when compared with other target genes. Taken together, SbZIP9 and SbFOMT-like were upregulated and downregulated by an extra K supply under Cd stress, suggesting that SbZIP9 and SbFOMT-like enhances and declines Cd accumulation as regulated by K addition in sweet sorghum respectively.

Transcriptional responses and secondary metabolites variation of tomato plant in response to tobacco mosaic virus infestation

The present study focused on the impact of infection with the tobacco mosaic virus (TMV). Specifically, changes in phytochemicals and gene activity related to pathogenesis-related and phenylpropanoid pathway genes in tomato plants (Solanum lycopersicum L.) during a period of 2–14 days post-inoculation (dpi). According to TEM investigation and coat protein sequence analysis, the purified TMV Egyptian AM isolate (PP133743) has a rod-shaped structure with a diameter of around 110 nm. The RT-qPCR analysis revealed that PR-1 showed an initial increase after TMV infection, as seen in the time-course analysis. In contrast, PR-2 was consistently elevated throughout the infection, suggesting a stronger reaction to the virus and suppressing PAL expression at 6 to 14 dpi. The expression levels of HQT and CHS transcripts exhibited alternating patterns of up-regulation and down-regulation at different time intervals. The HPLC and GC–MS analysis of control- and TMV-infected tomato extracts revealed that different phenolic, flavonoid, and fatty acid compounds were increased (such as naringenin, rutin, flavone, ferulic acid, and pyrogallol) or significantly decreased (such as salicylic acid and chlorogenic acid) after TMV infection. The ability of TMV to inhibit most polyphenolic compounds could potentially accelerate the viral life cycle. Consequently, focusing on enhancing the levels of such suppressed compounds may be critical for developing plant viral infection management strategies.

Increasing salinity sequentially induces salt tolerance responses in Szarvasi-1 energy grass

Soil salinity causes severe physiological disorders, decline in biomass, and crop production worldwide becoming more critical with global climate change. Consequently, salt-tolerant varieties received major focus in all sectors of agriculture. Biomass plants such as Szarvasi-1 energy grass (Elymus elongatus subsp. ponticus cv. Szarvasi-1) may play an important role in energy production if they are tolerant to environmental stresses. In this study, Szarvasi-1 energy grass has been investigated to reveal its tolerance to 50–200 mM NaCl in hydroponics. Significant decline in stomatal conductance appeared at 100 mM NaCl treatment but fresh and dry weight and the maximal quantum efficiency of PSII decreased only at 200 mM NaCl. Relative water content and total chlorophyll concentration did not change compared to the control. Leaf water potential was maintained at the control level for one week NaCl exposure, decrease became significant only after two weeks. Malondialdehyde concentration did not refer to oxidative stress. In the element composition of the plants, remarkable increase was found only for Mo whereas Ca, K, S, P, Mn decreased compared to the control. K to Na ratio remained higher than one in the shoot even at 200 mM NaCl. Salt treatment caused temporal and concentration-dependent changes in the expression of genes in the phenylpropanoid pathway, Na transport, photosynthesis, and cellular protection and repair. Szarvasi-1 was found to be fairly tolerant to NaCl which induced a sequential response switching on vacuolar compartmentalization at 50 mM, Na efflux at 100 mM, and cellular protection and repair at 200 mM.

Hydrogen Sulfide Improves Postharvest Quality of Okra (Abelmoschus esculentus (L.) Moench) Pods by Enhancing Antioxidant Capacity and Delaying Lignification.

Okra (Abelmoschus esculentus (L.) Moench) pod storage is challenging due to its high water content and tendency to lignify. Sodium hydrosulfide (NaHS) served as an H2S donor in this investigation. Compared with the control group, the group treated with 0.5 mmol/L NaHS solution effectively maintained the appearance quality, and its weight loss was only 6.21% at 20 days. The H2S treatment not only preserved tissue nutrients but also significantly enhanced catalase (CAT), ascorbic acid peroxidase (APX), and superoxide dismutase (SOD) activities while decreasing oxidant damage. In addition, H2S slowed down lignin synthesis by inhibiting the activities of key enzymes such as phenylalanine ammonialyase (PAL), cinnamate 4-hydroxylase (C4H), and cinnamyl alcohol dehydrogenase (CAD) in the lignin biosynthesis pathway. Transcriptome analysis revealed that H2S affects 34 genes in the phenylpropanoid biosynthesis pathway, such as AePAL, Ae4CL1, AeCCOAOMT1, AePOD, etc., which inhibit lignin synthesis of okra pods. All in all, moderate H2S can improve postharvest quality and extend the shelf-life of okra pods by enhancing antioxidant capacity and delaying lignification; the results will provide an overview of its application in the preservation of okra pods.

Chlorophyll deficiency in Agave angustifolia Haw.: unveiling the impact on secondary metabolite production.

The albino phenotype of Agave angustifolia Haw. accumulates higher levels of phenylalanine and phenylpropanoids, while the green phenotype has a greater concentration of phenolic compounds. The metabolic consequences of chlorophyll deficiency in plants continue to be a captivating field of research, especially in relation to production of metabolic compounds. This study conducts a thorough analysis of the metabolome in green (G), variegated (V), and albino (A) phenotypes of Agave angustifolia Haw. Specifically, it examines the differences in the accumulation of compounds related to the phenylpropanoid and flavonoid biosynthesis pathways. Methanol extracts of leaf and meristem tissues from the three phenotypes grown in vitro were analyzed using liquid chromatography coupled with quadrupole time-of-flight high-resolution mass spectrometry (UPLC-MS-QTOF) for untargeted metabolomics and triple quadrupole (QqQ) mass spectrometry for targeted metabolomic analyses. By employing these methods, we discovered notable differences in the levels of important metabolites such as L-phenylalanine, 4-hydroxyphenylpyruvic acid, and various flavonoids among the different phenotypes. The results of our study indicate that the A phenotype shows a significant increase in the levels of phenylalanine and phenylpropanoids in both leaf and meristem tissues. This is in contrast to a decrease in flavonoids, suggesting a metabolic reprogramming to compensate for the lack of chlorophyll. Significantly, compounds such as kaempferol-3-O-glucoside and rutin exhibited significant quantitative reduction in the A leaves, suggesting a subtle modification in the production of flavonols and potentially a changed mechanism for antioxidant protection. This study emphasizes the complex metabolic changes in A. angustifolia´s chlorophyll-deficient phenotypes, providing insight into the complex interplay between primary and secondary metabolism in response to chlorophyll deficiency. Our research not only enhances the comprehension of plant metabolism in albino phenotypes but also opens new avenues for exploring the biochemical and genetic basis of such adaptations, with potential biotechnological applications of these distinct plant variants.

MiRNA Sequencing Analysis in Maize Roots Treated with Neutral and Alkaline Salts.

Soil salinization/alkalization is a complex environmental factor that includes not only neutral salt NaCl but also other components like Na2CO3. miRNAs, as small molecules that regulate gene expression post-transcriptionally, are involved in plant responses to abiotic stress. In this study, maize seedling roots were treated for 5 h with 100 mM NaCl, 50 mM Na2CO3, and H2O, respectively. Sequencing analysis of differentially expressed miRNAs under these conditions revealed that the Na2CO3 treatment group had the most differentially expressed miRNAs. Cluster analysis indicated their main involvement in the regulation of ion transport, binding, metabolism, and phenylpropanoid and flavonoid biosynthesis pathways. The unique differentially expressed miRNAs in the NaCl treatment group were related to the sulfur metabolism pathway. This indicates a significant difference in the response patterns of maize to different treatment groups. This study provides theoretical evidence and genetic resources for further analysis of the molecular mechanisms behind maize's salt-alkali tolerance.

Integrated transcriptomic and metabolomic analysis reveals the molecular profiles of dynamic variation in Lilium brownii var. viridulum suffering from bulb rot.

Lilium brownii var. viridulum, known as Longya lily, is a well-known medicinal and edible plant in China. Bulb rot is a common disease in Longya lily cultivation that severely affects the yield and quality of lilies. According field investigations, we found that different Longya lily plants in the same field had different degrees of resistance to root rot. To find the reasons leading to the difference, we performed metabolomic and transcriptomic analyses of Longya lily with different degrees of disease. The transcriptomic analyses showed that the number of differentially expressed genes increased in early and mid-stage infections (LYBH2 and LYBH3), while decreased in late-stage infection (LYBH4). A total of 2309 DEGs showed the same expression trend in diseased bulb compared healthy bulb (LYBH1). The transcription factors (TFs) analysis of DEGs showed that several common TFs, like WRKY, bHLH, AP2/ERF-ERF and MYB, were significantly activated in bulbs after decay. The metabolomic analyses showed that there were 794 differentially accumulated metabolites, and metabolites with significant changes in relative content largely were phenolic acids, followed by flavonoids and amino acids and derivatives. The combined analysis of transcriptome and metabolome indicated that phenylpropanoid biosynthesis pathway was crucial in Longya lily resistance to bulb rot. Therefore, we speculated that the different degree of resistance to bulb rot in Longya lily may be related to the transcript levels of gene and contents of metabolites in the phenylpropanoid biosynthesis pathway. Overall, these results elucidate the molecular responses of Longya lily to bulb rot and lay a theoretical foundation for breeding resistant varieties.

Infestation of Rice Striped Stem Borer (Chilo suppressalis) Larvae Induces Emission of Volatile Organic Compounds in Rice and Repels Female Adult Oviposition.

Plants regulate the biosynthesis and emission of metabolic compounds to manage herbivorous stresses. In this study, as a destructive pest, the pre-infestation of rice striped stem borer (SSB, Chilo suppressalis) larvae on rice (Oryza sativa) reduced the subsequent SSB female adult oviposition preference. Widely targeted volatilomics and transcriptome sequencing were used to identify released volatile metabolic profiles and differentially expressed genes in SSB-infested and uninfested rice plants. SSB infestation significantly altered the accumulation of 71 volatile organic compounds (VOCs), including 13 terpenoids. A total of 7897 significantly differentially expressed genes were identified, and genes involved in the terpenoid and phenylpropanoid metabolic pathways were highly enriched. Correlation analysis revealed that DEGs in terpenoid metabolism-related pathways were likely involved in the regulation of VOC biosynthesis in SSB-infested rice plants. Furthermore, two terpenoids, (-)-carvone and cedrol, were selected to analyse the behaviour of SSB and predators. Y-tube olfactometer tests demonstrated that both (-)-carvone and cedrol could repel SSB adults at higher concentrations; (-)-carvone could simultaneously attract the natural enemies of SSB, Cotesia chilonis and Trichogramma japonicum, and cedrol could only attract T. japonicum at lower concentrations. These findings provide a better understanding of the response of rice plants to SSB and contribute to the development of new strategies to control herbivorous pests.