Search Results (21)

Cinnamoyl-CoA reductases (CCRs) and their homologs, CCR-like proteins, play key roles in plant secondary metabolism and defense against environmental stresses; however, their functions in heat stress responses remain unclear. In this study, phylogenetic and sequence alignment analyses revealed that OsCCR14 encodes a CCR-like protein. qRT-PCR assays showed that OsCCR14 is predominantly expressed in roots and is induced by heat stress. Notably, overexpression of OsCCR14 increased lignin content, and transgenic plants with enhanced OsCCR14 expression exhibited higher flavonoid accumulation in roots. Conversely, knockout of OsCCR14 reduced flavonoid content and impaired seedling heat tolerance. Furthermore, OsCCR14 overexpression improved heat tolerance, accompanied by increased root lignification and flavonoid accumulation. These results indicate that OsCCR14 acts as a critical regulator of lignin and flavonoid metabolism, thereby providing a potential target for enhancing crop heat tolerance. Full article

Hydroxytyrosol is a natural phenolic compound found in olives. Phenylacetaldehyde reductase (PAR) is a key enzyme in the final step of the hydroxytyrosol biosynthesis pathway in olives. However, genome-wide studies on the PAR gene family in olives have not been reported. In this study, 21 genes were identified through a genome-wide analysis. Phylogenetic analysis classified these genes into three subgroups: PAR, CCR (Cinnamoyl-CoA reductase), and DFR (Dihydroflavonol 4-reductase). Expression pattern analysis suggested that genes within these subfamilies may play crucial roles in the biosynthesis of polyphenols, lignin, and anthocyanins, respectively. Three-dimensional structural modeling and molecular docking of the OePAR1 revealed that hydrogen bonds, hydrophobic interactions, and π–π stacking interactions collectively influence the affinity between PAR and its substrates. Residues at the active site form hydrogen bonds, with variations contributing to substrate specificity. The substrate with the strongest affinity for OePAR1 was identified as 3,4-dihydroxyphenylacetaldehyde (3, 4-DHPAA), with a binding energy of −4.98 kcal/mol, in agreement with previous enzymatic activity validation. Subcellular localization studies revealed that OePAR1 is localized to the chloroplast. This study provides essential insights into the biological functions of OePARs in olives and lays the groundwork for enhancing olive oil quality through genetic engineering. Full article

Mulberry (Morus alba L.) is a significant economic tree species in China. The lignin component serves as a critical limiting factor that impacts both the forage quality and the conversion efficiency of mulberry biomass into biofuel. Cinnamoyl CoA reductase (CCR; EC 1.21.1.44) and cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.95) are the key enzymes that catalyze the final two reductive steps in the biosynthesis of monolignols. In this study, we conducted a comprehensive functional analysis to validate the predominant CCR genes involved in monolignol biosynthesis. In this study, we initially validated the predominant CCR genes implicated in monolignol biosynthesis through an extensive functional analysis. Phylogenetic analysis, tissue-specific expression profiling and enzymatic assays indicated that MaCCR1 is the authentic CCR involved in lignin biosynthesis. Furthermore, the expression level of MaCCR1 exhibited a significant positive correlation with lignin content, and the down-regulation of MaCCR1 via virus-induced gene silencing resulted in altered lignin content in mulberry. The down-regulation of MaCCR1 and MaCAD3/4, both individually and concurrently, exhibited markedly different effects on lignin content and mulberry growth. Specifically, the simultaneous down-regulation of MaCCR1 and MaCAD3/4 significantly altered lignin content in mulberry, resulting in dwarfism of the plants. Conversely, the down-regulation of MaCAD3/4 alone not only decreased lignin content but also led to an increase in biomass. These findings offer compelling evidence elucidating the roles of MaCCRs in mulberry and identify specific target genes, thereby providing a crucial foundation for the genetic modification of lignin biosynthesis. Full article

Background: It is currently believed that breeding priorities, including maize breeding, should focus on introducing varieties with greater utility value, specifically higher yields, into production. Global modern maize breeding relies on various molecular genetics techniques. Using the above mentioned technologies, we can identify regions of the genome that are associated with various phenotypic traits, including yield, which is of fundamental importance for understanding and manipulating these regions. Objectives: The aim of the study was to analyze the expression of candidate genes associated with maize yield. To better understand the function of the analyzed genes in increasing maize yield, their expression in different organs and tissues was also assessed using publicly available transcriptome data. Methods: RT-qPCR analyses were performed using iTaq Universal SYBR Green Supermix (Bio-Rad, Hercules, CA, USA) and CFX96 Touch Real-Time PCR Detection System (Bio-Rad, Hercules, CA, USA). Each of the performed RT-qPCR experiments consisted of three biological replicates and three technical replicates, the results of which were averaged. Results: The research results allowed us to select three out of six candidate genes (cinnamoyl-CoA reductase 1—CCR1, aspartate aminotransferase—AAT and sucrose transporter 1—SUT1), which can significantly affect grain yield in maize. Not only our studies but also literature reports clearly indicate the participation of CCR1, AAT and SUT1 in the formation of yield. Identified molecular markers located within these genes can be used in breeding programs to select high yielding maize genotypes. Full article

Sunburn stress is one of the main environmental stress factors that seriously affects the fruit development and quality of Chinese olive, a tropical and subtropical fruit in south China. Therefore, the understanding of the changes in physiological, biochemical, metabolic, and gene expression in response to sunburn stress is of great significance for the industry and breeding of Chinese olive. In this study, the different stress degrees of Chinese olive fruits, including serious sunburn injury (SSI), mild sunburn injury (MSI), and ordinary (control check, CK) samples, were used to identify the physiological and biochemical changes and explore the differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) by using transcriptomics and metabolomics. Compared with CK, the phenotypes, antioxidant capacity, and antioxidant-related enzyme activities of sunburn stress samples changed significantly. Based on DEG-based KEGG metabolic pathway analysis of transcriptomics, the polyphenol and flavonoid-related pathways, including phenylpropanoid biosynthesis, sesquiterpenoid, and triterpenoid biosynthesis, monoterpene biosynthesis, carotenoid biosynthesis, isoflavonoid biosynthesis, flavonoid biosynthesis, were enriched under sunburn stress of Chinese olive. Meanwhile, 33 differentially accumulated polyphenols and 99 differentially accumulated flavonoids were identified using metabolomics. According to the integration of transcriptome and metabolome, 15 and 8 DEGs were predicted to regulate polyphenol and flavonoid biosynthesis in Chinese olive, including 4-coumarate-CoA ligase (4CL), cinnamoyl-CoA reductase (CCR), cinnamoyl-alcohol dehydrogenase (CAD), chalcone synthase (CHS), flavanone-3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), and anthocyanidin synthase (ANS). Additionally, the content of total polyphenols and flavonoids was found to be significantly increased in MSI and SSI samples compared with CK. Our research suggested that the sunburn stress probably activates the transcription of the structural genes involved in polyphenol and flavonoid biosynthesis in Chinese olive fruits to affect the antioxidant capacity and increase the accumulation of polyphenols and flavonoids, thereby responding to this abiotic stress. Full article

The ‘Huangguan’ pear is one of the high-quality pear cultivars produced in China. However, the bagged fruit of the ‘Huangguan’ pear often suffers from peel browning spots after rain during their mature period. In this study, in an effort to discover the impact of bagging treatments on the occurrence of peel browning spots and fruit quality, fruits were covered by single-layer, two-layer, or triple-layer paper bags six weeks after reaching full bloom. The results showed that the bagged fruits were characterized by smooth surfaces and reduced lenticels compared with the unbagged ones. The unbagged and the two-layer bagged fruits had yellow/green peels, while the single- and triple-layer bagged ones had yellow/white peels. Compared with the unbagged fruits, the bagged fruits had higher vitamin C (Vc) contents and values of peel color indexes L and a and lower soluble solid contents (SSCs), titratable acid (TA) contents, absorbance index differences (I_AD), and b values. Additionally, the triple-layer bagged group was superior to other groups in terms of fruit quality, but it also had the maximum incidence of peel browning spots. Before and after the appearance of peel browning spots, the bagged fruits had smoother and thinner cuticles compared with the unbagged ones. Furthermore, the triple-layer bagged fruits had minimum lignin contents and maximum phenolic contents in their peels, with minimum activity of lignin synthesis-related enzymes such as phenylalanine ammonia lyase (PAL), peroxidase (POD), and polyphenol oxidase (PPO), as well as minimum expressions of relevant genes such as cinnamyl alcohol dehydrogenase (CAD), cinnamoyl CoA reductase (CCR), 4-coumarate: coenzyme A ligase (4CL6), and cinnamate 4-hydroxylase (C4H1). It was deduced that POD activity and the relative expressions of CAD9, CCR3, CCR4, and CCR5 may play key roles in the occurrence of peel browning spots. In summary, lignin synthesis affected the incidence of peel browning spots in bagged ‘Huangguan’ pears. This study provides a theoretical basis for understanding the incidence of peel browning spots in ‘Huangguan’ pears. Full article

Agarwood is a resinous heartwood of Aquilaria sinensis that is formed in response to mechanical wounding. However, the transcriptional response of A. sinensis to mechanical wounding during the agarwood formation process is still unclear. Here, three five-year-old A. sinensis trees were mechanically damaged by a chisel, and time-series transcriptomic analysis of xylem tissues in the treated area (TA) was performed at 15 (TA1), 70 (TA2) and 180 days after treatment (TA3). Samples from untreated areas at the corresponding time points (UA1, UA2, UA3, respectively) were collected as controls. A total of 1862 (TA1 vs. UA1), 961 (TA2 vs. UA2), 1370 (TA3 vs. UA3), 3305 (TA2 vs. TA1), 2625 (TA3 vs. TA1), 2899 (TA3 vs. TA2), 782 (UA2 vs. UA1), 4443 (UA3 vs. UA1) and 4031 (UA3 vs. UA2) genes were differentially expressed (DEGs). Functional enrichment analysis showed that DEGs were significantly enriched for secondary metabolic processes, signal transduction and transcriptional regulation processes. Most of the genes involved in lignin biosynthesis were more abundant in the TA groups, which included phenylalanine ammonia-lyase, 4-coumarate CoA ligase, cinnamate 4-hydroxylase, caffeoyl-CoA O-methyltransferase and cinnamoyl-CoA reductase. DEGs involved in sesquiterpene biosynthesis were also identified. Hydroxymethylglutaryl-CoA synthase, 3-hydroxy-3-methylglutaryl-coenzyme A reductase, phosphomevalonate kinase and terpene synthase genes were significantly increased in the TA groups, promoting sesquiterpene biosynthesis in the wounded xylem tissues. The TF-gene transcriptomic networks suggested that MYB DNA-binding, NAM, WRKY, HLH and AP2 TFs co-expressed with genes related to lignin and sesquiterpene synthesis, indicating their critical regulatory roles in the biosynthesis of these compounds. Overall, our study reveals a dynamic transcriptional response of A. sinensis to mechanical wounding, provides a resource for identifying candidate genes for molecular breeding of agarwood quality, and sheds light on the molecular mechanisms of agarwood formation in A. sinensis. Full article

The jujube witches’ broom (JWB) disease is a severe threat to jujube trees, with only a few cultivars being genuinely tolerant or resistant to phytoplasma. The defense mechanism of jujube trees against phytoplasma is still unclear. In this study, we aimed to investigate the tolerance mechanism of Indian jujube ‘Cuimi’ to JWB and identify the key genes that contribute to JWB high tolerance. Based on the symptoms and phytoplasma concentrations after infection, we confirmed the high tolerance of ‘Cuimi’ to JWB. Comparative transcriptome analysis was subsequently performed between ‘Cuimi’ and ‘Huping’, a susceptible cultivar of Chinese jujube. Unique gene ontology (GO) terms were identified in ‘Cuimi’, such as protein ubiquitination, cell wall biogenesis, cell surface receptor signaling pathway, oxylipin biosynthetic process, and transcription factor activity. These terms may relate to the normal development and growth of ‘Cuimi’ under phytoplasma infection. We identified 194 differential expressed genes related to JWB high tolerance, involved in various processes, such as reactive oxygen species (ROS), Ca²⁺ sensors, protein kinases, transcription factors (TFs), lignin, and hormones. Calmodulin-like (CML) genes were significantly down-regulated in infected ‘Cuimi’. We speculated that the CML gene may act as a negative regulatory factor related to JWB high tolerance. Additionally, the cinnamoyl-CoA reductase-like SNL6 gene was significantly up-regulated in infected ‘Cuimi’, which may cause lignin deposition, limit the growth of phytoplasma, and mediate immune response of ‘Cuimi’ to phytoplasma. Overall, this study provides insights into the contribution of key genes to the high tolerance of JWB in Indian jujube ‘Cuimi’. Full article

The banana is prone to chilling injury (CI) at low temperature and showing a series of chilling symptoms, such as peel browning, etc. Lignification is a response to abiotic stress and senescence, which is an important manifestation of fruits and vegetables during chilling exposure. However, little is known about the lignification of bananas during low-temperature storage. Our study explored the characteristics and lignification mechanism of banana fruits during low-temperature storage by analyzing the changes of chilling symptoms, oxidative stress, cell wall metabolism, microstructures, and gene expression related to lignification. The results showed that CI inhibited post-ripening by effecting the degradation of the cell wall and starch and accelerated senescence by increasing O²⁻ and H₂O₂ content. For lignification, Phenylalanine ammonia-lyase (PAL) might start the phenylpropanoid pathway of lignin synthesis. Cinnamoyl-CoA reductase 4 (CCR4), cinnamyl alcohol dehydrogenase 2 (CAD2), and 4-coumarate--CoA ligase like 7 (4CL7) were up-regulated to promote the lignin monomer’s synthesis. Peroxidase 1 (POD1) and Laccase 3 (LAC3) were up-regulated to promote the oxidative polymerization of lignin monomers. These results suggest that changes of the cell wall structure and cell wall metabolism, as well as lignification, are involved in the senescence and quality deterioration of the banana after chilling injury. Full article

Different southern grape (Muscadine) genotypes (Muscadinia rotundifolia Michx.) were evaluated for their contents of metabolites in ripe berries. The metabolome study identified 331 metabolites in ripening skin and seed tissues. The major chemical groups were organic acids, fatty acyls, polyketides, and organic heterocycle compounds. The metabolic pathways of the identified metabolite were mainly arginine biosynthesis, D-glutamine, D-glutamate metabolism, alanine, aspartate metabolism, aminoacyl-tRNA biosynthesis, and citrate cycle. Principal component analysis indicated that catechin, gallic acid, and epicatechin-3-gallate were the main metabolites existing in muscadine seed extracts. However, citramalic and malic acids were the main metabolites contributing to muscadine skin extracts. Partial least-squares discriminant analysis (VIP > 1) described 25 key compounds indicating the metabolome in muscadine tissues (skin and seed). Correlation analysis among the 25 compounds and oxidation inhibition activities identified five biomarker compounds that were associated with antioxidant activity. Catechin, gallic acid, epicatechin-3-gallate, fertaric acid, and procyanidin B1 were highly associated with DPPH, FRAP, CUPRAC, and ABTS. The five biomarker compounds were significantly accumulated in the seed relative to the skin tissues. An evaluation of 15 antioxidant-related genes represented by the 3-dehydroquinate dehydratase (DHD), shikimate kinase (SK), chalcone synthase (CHS), anthocyanidin reductase (ANR), laccase (LAC), phenylalanine ammonia-lyase (PAL), dihydroflavonol 4-reductase (DFR), 3-dehydroquinate synthase (DHQS), chorismate mutase (CM), flavanone-3-hydroxylase (F3H), cinnamoyl-CoA reductase (CCR), cinnamyl alcohol dehydrogenase (CAD), leucoanthocyanidin reductase (LAR), gallate 1-β-glucosyltransferase (UGT), and anthocyanidin 3-O-glucosyltransferase (UFGT) encode critical enzymes related to polyphenolics pathway throughout four developmental stages (fruit-set FS, véraison V, ripe-skin R, and ripe-seed; S) in the C5 genotype demonstrated the dramatic accumulation of all transcripts in seed tissue or a developmental stage-dependent manner. Our findings suggested that muscadine grape seeds contain essential metabolites that could attract the attention of those interested in the pharmaceutical sector and the plant breeders to develop new varieties with high nutraceutical value. Full article

Sida cordifolia is a medicinal shrub that is conventionally used in the Indian system of medicine;however, the genes contributing to its medicinal properties have been minimally explored, thus limiting its application. High-throughputsequencing and Liquid Chromatography with tandem mass spectrometry(LC-MS/MS) technologies were applied to unravel the medicinally important bioactive compounds. As a result, transcriptomic sequencing generated more than 12 GB of clean data, and 187,215 transcripts were obtained by de novoassembly. These transcripts were broadly classified into 20 classes, based on the gene ontology classification, and 6551 unigenes were annotated using Kyoto Encyclopedia of Genes and Genomes (KEGG) database with more than 142 unigenes involved in the biosynthesis of secondary metabolites. LC-MS/MS analysis of three tissues of Sida cordifolia revealed that acacetin and procyanidin are some important metabolites identified thatcontribute to its medicinal value. Several key enzymes witha crucial role in phenylpropanoid and flavonoid biosynthetic pathways were identified, especially phenylalanine ammonia lyase, which might be an important rate-limiting enzyme. Real-Time Quantitative Reverse Transcription Polymerase chain reaction (qRT-PCR) analysis revealed enzymes, such as Phenylalanine ammonia lyase (PAL), Cinnamyl alcohol dehydrogenase 1 (CAD), Cinnamoyl-CoA reductase 1 (CF1) and Trans cinnamate 4-monooxygenase(TCM), which were predominantly expressed in root compared to leaf and stem tissue. The study provides a speculative insight for the screening of active metabolites and metabolic engineering in Sida cordifolia. Full article

The biological process of anther development is very complex. It remains largely unclear how the cinnamoyl–CoA reductase (CCR) encoding genes function in the regulation of anther development in plants. Here, we establish that the CCR family gene OsCCR18 is essential for maintaining male fertility in rice. The OsCCR18 transcripts were greatly abundant in the panicles at the S4 and S5 developmental stages in rice. The subcellular localization of OsCCR18 proteins was in the nucleus of the rice. The knockout of the OsCCR18 gene resulted in a severely abnormal degradation of the tapetum as well as the abnormal development of granular Ubisch bodies, leading to the inability to form normal pollen in the mutants. Compared with the wild–type (WT) rice, the osccr18 mutants had no visible pollen grains and had entirely male sterility. Furthermore, several anther development–related genes, including OsPDA1, OsDTD, OsC6, OsACOS12, OsTDR, OsWDA1, OsDPW, OsCYP703A3, and OsNOP, were significantly lower expressed in the panicles at the stages from S5 to S8 in the osccr18 mutants than in the WT plants. Additionally, hundreds of genes involved in phenylpropanoid biosynthesis, fatty acid synthesis and metabolism exhibited distinct expression patterns between the WT and mutants, which may be crucial for controlling anther development in rice. These findings add a new regulatory role to CCR family gene–mediated male fertility in rice. Full article

Cinnamoyl-CoA reductase (CCR) is a pivotal enzyme in plant lignin synthesis, which has a role in plant secondary cell wall development and environmental stress defense. Alfalfa is a predominant legume forage with excellent quality, but the lignin content negatively affects fodder digestibility. Currently, there is limited information on CCR characteristics, gene expression, and its role in lignin metabolism in alfalfa. In this study, we identified 30 members in the CCR gene family of Medicago sativa. In addition, gene structure, conserved motif, and evolution analysis suggested MsCCR1–7 presumably functioned as CCR, while the 23 MsCCR-likes fell into three categories. The expression patterns of MsCCRs/MsCCR-likes suggested their role in plant development, response to environmental stresses, and phytohormone treatment. These results were consistent with the cis-elements in their promoters. Histochemical staining showed that lignin accumulation gradually deepened with the development, which was consistent with gene expression results. Furthermore, recombinant MsCCR1 and MsCCR-like1 were purified and the kinetic parameters were tested under four substrates. In addition, three-dimensional structure models of MsCCR1 and MsCCR-like1 proteins showed the difference in the substrate-binding motif H212(X)2K215R263. These results will be useful for further application for legume forage quality modification and biofuels industry engineering in the future. Full article

Cinnamoyl-CoA reductases (CCR) have a possible role in pungency formation of pepper because they can convert feruloyl-CoA, sinapoyl-CoA, and p-coumaroyl-CoA into lignin, which are also competitive precursors of capsaicin biosynthesis in phenylpropanoid metabolism. In this study, genome-wide CCR gene family, exon–intron structures, sequence homology, phylogenetic characterization, and promoters were analyzed in pepper. Two CCR genes were cloned from Capsicum chinense, their enzymic kinetic parameters and regulatory function were identified by heterologous expression, ectopic expression, and VIGS. In total, 38 genes were found as predicted CCRs or CCR-like proteins and were composed of 2–10 exons. The promoters of pepper CCRs contained growth, stress, hormone, and light-response elements. The affinity and catalytic efficiency of CcCCR1/2 to feruolyl-CoA was the highest. The analysis of metabolic substances showed that capsaicin content was negatively correlated with lignin and positively correlated with flavonoids. The highest expression of CcCCR1 was found in stems, the higher expression of CcCCR2 was found in stem and early fruit than other organs. CCR1, 2 had certain effects on capsaicin content by regulating related enzyme activity, CCR2 played a more important role in regulating pungency formation. Our results clarify the competitive mechanism between lignin and capsaicin biosynthesis and provide an explanation for spice regulation. Full article

The stem is an important organ in supporting plant body, transporting nutrients and communicating signals for plant growing. However, studies on the regulation of stem development in tomato are rather limited. In our study, we demonstrated that SlHB8 negatively regulated tomato stem development. SlHB8 belongs to homeo domain-leucine zipper Class III gene family transcription factors and expressed in all the organs examined including root, stem, leaves, flower, and fruit. Among these tissues, SlHB8 showed stable high expression level during tomato stem development. Overexpression of SlHB8 gene decreased stem diameter with inhibited xylem width and xylem cell layers, while loss of function of SlHB8gene increased the stem diameter and xylem width. The contents of lignin were decreased both in leaves and stems of SlHB8 overexpression plants. RNA-seq analysis on the stems of wild type and SlHB8 transgenic plants showed that the 116 DEGs (differential expressed genes) with reversible expression profiles in SlHB8-ox and SlHB8-cr plants were significantly enriched in the phenylpropanoid biosynthesis pathway and plant-pathogen pathway which were related to lignin biosynthesis and disease resistance. Meanwhile, the key genes involved in the lignin biosynthesis pathway such as SlCCR (cinnamoyl-CoA reductase), SlCYP73A14/C4H (cinnamate 4-hydroxylase), SlC3H (coumarate 3-hydroxylase) and SlCAD (cinnamoyl alcohol dehydrogenase) were down-regulated in both stem and leaves of SlHB8 overexpression plants, indicating a negative regulatory role of SlHB8 in the lignin biosynthesis and stem development. Full article