通讯机构：
[Jian Zhao] K;Key Laboratory of Tea Science of Ministry of Education, College of Horticulture, Hunan Agricultural University, Changsha 410011, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
aluminum and fluoride;organic acid;secondary metabolite;tea quality;tea safety
摘要：
Tea plants have adapted to grow in tropical acidic soils containing high concentrations of aluminum (Al) and fluoride (F) (as Al/F hyperaccumulators) and use secret organic acids (OAs) to acidify the rhizosphere for acquiring phosphorous and element nutrients. The self-enhanced rhizosphere acidification under Al/F stress and acid rain also render tea plants prone to accumulate more heavy metals and F, which raises significant food safety and health concerns. However, the mechanism behind this is not fully understood. Here, we report that tea plants responded to Al and F stresses by synthesizing and secreting OAs and altering profiles of amino acids, catechins, and caffeine in their roots. These organic compounds could form tea-plant mechanisms to tolerate lower pH and higher Al and F concentrations. Furthermore, high concentrations of Al and F stresses negatively affected the accumulation of tea secondary metabolites in young leaves, and thereby tea nutrient value. The young leaves of tea seedlings under Al and F stresses also tended to increase Al and F accumulation in young leaves but lower essential tea secondary metabolites, which challenged tea quality and safety. Comparisons of transcriptome data combined with metabolite profiling revealed that the corresponding metabolic gene expression supported and explained the metabolism changes in tea roots and young leaves via stresses from high concentrations of Al and F. The study provides new insight into Al- and F-stressed tea plants with regard to responsive metabolism changes and tolerance strategy establishment in tea plants and the impacts of Al/F stresses on metabolite compositions in young leaves used for making teas, which could influence tea nutritional value and food safety.
摘要：
The leaf is an important plant organ and is closely related to agricultural yield. Photosynthesis plays a critical role in promoting plant growth and development. Understanding the mechanism of leaf photosynthesis regulation will help improve crop yield. In this study, the pepper yellowing mutant was used as the experimental material, and the photosynthetic changes of pepper leaves (yl1 and 6421) under different light intensities were analyzed by chlorophyll fluorimeter and photosynthesis meter. Changes in proteins and enrichment of phosphopeptides in pepper leaves were determined. The results showed that different light intensities had significant effects on the chlorophyll fluorescence and photosynthetic parameters of pepper leaves. The differentially expressed proteins (DEPs) and differentially expressed phosphorylated proteins (DEPPs) were mainly involved in photosynthesis, photosynthesis-antenna proteins, and carbon fixation in photosynthetic organisms. In yl1 leaves, the phosphorylation levels of photosynthesis and photosynthesis-antenna proteins LHCA2, LHCA3, PsbC, PsbO, and PsbP were lower under low light treatment, but significantly higher under high light intensity compared with wild-type leaves. In addition, many proteins involved in the carbon assimilation pathway, including TKT, Rubisco, and PGK, were phosphorylated, and this modification level was significantly higher in yl1 than in the wild type under high light intensity. These results provide a new perspective for studying the photosynthesis mechanism of pepper under different light intensities.
摘要：
Scenting tea with Jasminum sambac is beneficial to forming a unique taste of jasmine tea, which is regulated by numerous compounds. To investigate the relationship between metabolites in jasmine and jasmine tea, as well as the impact of metabolites on the characteristic taste of jasmine tea, the liquid chromatography-mass spectrometry, sensory evaluation, and multivariate analysis were applied in this study. A total of 585 and 589 compounds were identified in jasmine tea and jasmine, respectively. After scented, jasmine tea added 70 compounds, which were believed to come from jasmine flowers. Furthermore, seventy-four compounds were identified as key characteristic compounds of jasmine tea, and twenty-two key differential metabolite compounds were believed to be used to distinguish jasmine tea scented differently and contribute to the taste of jasmine tea. Additionally, the relationship between taste compounds and aroma quality was also explored, and it was found that five compounds were positively correlated with the aroma properties of jasmine tea and seven compounds were negatively correlated with the aroma properties of jasmine tea. Overall, these findings provided insights into the future study of the mechanism of taste formation in jasmine tea and provided the theoretical basis for the production of jasmine tea.
通讯机构：
[Xiaohan Yang] B;Biosciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831 , USA<&wdkj&>U.S. DOE-Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831 , USA
摘要：
Agave REVEILLE1 regulates bud dormancy and bud break in Populus by repressing multiple dormancy-related genes and up-regulating bud break-related genes. Deciduous woody plants like poplar (Populus spp.) have seasonal bud dormancy. It has been challenging to simultaneously delay the onset of bud dormancy in the fall and advance bud break in the spring, as bud dormancy, and bud break were thought to be controlled by different genetic factors. Here, we demonstrate that heterologous expression of the REVEILLE1 gene (named AaRVE1) from Agave (Agave americana) not only delays the onset of bud dormancy but also accelerates bud break in poplar in field trials. AaRVE1 heterologous expression increases poplar biomass yield by 166% in the greenhouse. Furthermore, we reveal that heterologous expression of AaRVE1 increases cytokinin contents, represses multiple dormancy-related genes, and up-regulates bud break-related genes, and that AaRVE1 functions as a transcriptional repressor and regulates the activity of the DORMANCY-ASSOCIATED PROTEIN 1 (DRM1) promoter. Our findings demonstrate that AaRVE1 appears to function as a regulator of bud dormancy and bud break, which has important implications for extending the growing season of deciduous trees in frost-free temperate and subtropical regions to increase crop yield.
通讯机构：
[Yanlin Li; Xingyao Xiong] A;Authors to whom correspondence should be addressed.<&wdkj&>Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China<&wdkj&>Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding, Ministry of Education, Changsha 410128, China<&wdkj&>Hunan Mid-Subtropical Quality Plant Breeding and Utilization Engineering Technology Research Center, Changsha 410128, China<&wdkj&>College of Horticulture, Hunan Agricultural University, Changsha 410128, China<&wdkj&>Kunpeng Institute of Modern Agriculture, Foshan 528200, China<&wdkj&>School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore<&wdkj&>Authors to whom correspondence should be addressed.<&wdkj&>Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China<&wdkj&>College of Horticulture, Hunan Agricultural University, Changsha 410128, China
摘要：
This study employed a combination of ultraviolet spectrophotometry, LC-ESI-MS/MS system, and RNA-sequencing technology; the extracts and isolation of total RNA from the red and yellow leaf strains of red maple (Acer rubrum L.) at different developmental stages were subjected to an intercomparison of the dynamic content of chlorophyll and total anthocyanin, flavonoid metabolite fingerprinting, and gene expression. The metabonomic results indicated that one hundred and ninety-two flavonoids were identified, which could be classified into eight categories in the red maple leaves. Among them, 39% and 19% were flavones and flavonols, respectively. The metabolomic analysis identified 23, 32, 24, 24, 38, and 41 DAMs in the AR1018r vs. AR1031r comparison, the AR1018r vs. AR1119r comparison, the AR1031r vs. AR1119r comparison, the AR1018y vs. AR1031y comparison, the AR1018y vs. AR1119y comparison, and the AR1031y vs. AR1119y comparison, respectively. In total, 6003 and 8888 DEGs were identified in AR1018r vs. AR1031r comparison and in the AR1018y vs. AR1031y comparison, respectively. The GO and KEGG analyses showed that the DEGs were mainly involved in plant hormone signal transduction, flavonoid biosynthesis, and other metabolite metabolic processes. The comprehensive analysis revealed that caffeoyl-CoA 3-O-methyltransferase (Cluster-28704.45358 and Cluster-28704.50421) was up-regulated in the red strain but down-regulated in the yellow strain, while Peonidin 3-O-glucoside chloride and Pelargonidin 3-O-beta-D-glucoside were up-regulated in both the red and yellow strains. By successfully integrating the analyses on the behavior of pigment accumulation, dynamics of flavonoids, and differentially expressed genes with omics tools, the regulation mechanisms underlying leaf coloring in red maple at the transcriptomic and metabolomic levels were demonstrated, and the results provide valuable information for further research on gene function in red maple.
关键词：
Urban parks;Cool island intensity;Landscape morphology;Thermal environment;Simultaneous equation modeling
摘要：
Urban parks have significant cooling effects that alleviate the urban heat island (UHI). The park cool island intensity (PCII), the temperature difference between outside and inside a park, is a widely used indicator of a park’s cooling ability. Understanding the driving factors of the PCII is crucial for better urban park planning and management. Taking the subtropical city of Changsha, China, as a case study, factors such as the landscape patterns inside and outside a park and the geometric morphology of a park were investigated, based on 153 urban parks. A novel simultaneous equation modeling (SEM) approach was used to account for the mutual interactions between the temperatures of a park and its buffer. The results show that: (1) Park geometric morphology and landscape patterns inside and outside the park all significantly impact the PCII. Specifically, doubling the park size can increase the PCII by 0.8 K. Increasing by ten percent the tree cover and water cover in the park can enhance the PCII by 0.12 K and 0.41 K, respectively. Increasing the mean tree patch size by 1 ha can increase the PCII by 0.43 K. Decreasing by one unit the mean tree patch shape index can increase the PCII by 0.31 K. (2) An elasticity analysis, which measures the PCII percent change resulting from one percent change in a driving factor, indicates the relative importance ranking of these driving factors: percent cover of impervious surface outside the park (0.77), park size (0.72), percent cover of tree within the park (0.51), percent cover of water within the park (0.12), and mean patch size of tree cover within the park (0.086). To enhance the PCII, we recommend building parks in the hot areas of the city, increasing their size, increasing the percentages of tree cover and water cover in the park, and optimizing the spatial configuration of the tree cover in the park (i.e., aggregating trees in a smaller number of large patches and reducing the irregularity of tree patches).
通讯机构：
[Shanhan Cheng; Jialei Ji] A;Authors to whom correspondence should be addressed.<&wdkj&>Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, College of Horticulture, Hainan University, Haikou 570228, China<&wdkj&>Authors to whom correspondence should be addressed.<&wdkj&>Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
摘要：
Cabbage (Brassica oleracea var. capitata) is a vegetable rich in glucosinolates (GSLs) that have proven health benefits. To gain insights into the synthesis of GSLs in cabbage, we systematically analyzed GSLs biosynthetic genes (GBGs) in the entire cabbage genome. In total, 193 cabbage GBGs were identified, which were homologous to 106 GBGs in Arabidopsis thaliana. Most GBGs in cabbage have undergone negative selection. Many homologous GBGs in cabbage and Chinese cabbage differed in expression patterns indicating the unique functions of these homologous GBGs. Spraying five exogenous hormones significantly altered expression levels of GBGs in cabbage. For example, MeJA significantly upregulated side chain extension genes BoIPMILSU1-1 and BoBCAT-3-1, and the expression of core structure construction genes BoCYP83A1 and BoST5C-1, while ETH significantly repressed the expression of side chain extension genes such as BoIPMILSU1-1, BoCYP79B2-1, and BoMAMI-1, and some transcription factors, namely BoMYB28-1, BoMYB34-1, BoMYB76-1, BoCYP79B2-1, and BoMAMI-1. Phylogenetically, the CYP83 family and CYP79B and CYP79F subfamilies may only be involved in GSL synthesis in cruciferous plants. Our unprecedented identification and analysis of GBGs in cabbage at the genome-wide level lays a foundation for the regulation of GSLs synthesis through gene editing and overexpression.
摘要：
Theanine is a unique secondary metabolite in tea plants and contributes to the umami taste and health benefits of tea. However, theanine biosynthesis in tea plants is not fully understood, and its mechanism of transcriptional regulation remains poorly reported. Theanine content was significantly correlated with the expression of theanine biosynthesis-related gene CsGS1c and transcription factor CsMYB42 in different leaf positions and picking times, but there was no significant correlation in different tissues of albino tea plant 'Anjibaicha'. This suggests that CsMYB42 may regulate CsGS1c to synthesize theanine in albino tea leaves, and the regulation is tissue specific. CsMYB42 is a nuclear-localized R2R3-MYB transcription factor gene with transcriptional activation activity. Yeast one-hybrid assay and electrophoretic mobility shift assay confirmed the direct binding of CsMYB42 to the promoter of CsGS1c. Luciferase assay showed that CsMYB42 activates the CsGS1c expression. Furthermore, the inhibition of CsMYB42 using an antisense oligonucleotide in tea leaves decreased CsGS1c expression and theanine content. These results indicate that CsMYB42 plays a crucial role in activating the expression of CsGS1c and may be involved in the biosynthesis of theanine in albino tea leaves. This study provides fresh insights into the tissue-specific regulation of theanine biosynthesis, which laid a foundation for breeding high-theanine tea plants.
关键词：
activity zone;landscape features;seasonal and diurnal variations;urban park;visitation density
摘要：
Urban parks are the main place for physical activities, generating numerous benefits to enhance human well-being. Many studies have investigated the impacts of landscape features on park visitation but ignored their seasonal and diurnal variations. Taking the Hunan Martyr Park in China as an example, this study aims to assess the seasonal and diurnal variations in the impacts of landscape features on visitation density. We quantified visitation density for 109 activity zones for both daytime and nighttime in summer and winter and investigated the impacts of landscape features of the activity zone and the surrounding environments on visitation density based on 16 quantitative indicators. The results show that: (1) The impacts of ground condition, connection to water, distance to park entrances, and distance to stores were consistent in different periods. Paved activity zones, zones close to water, zones further away from the park entrances, and zones closer to the stores had significantly higher visitation density. (2) Shading degree, connected pathway, and distance to toilets had contrasting impacts between summer and winter. Zones with a higher shading degree attracted more visitors in summer and deterred visitors in winter. Zones with fewer pathways connected and zones farther away from toilets had higher visitation density in summer but not in winter. (3) Shading degree, number of trees, presence of facilities (e.g., benches, tables, pavilion, and light devices), and connected pathway had contrasting impacts between daytime and nighttime. Zones with a high shading degree, zones with benches and pavilions, and zones without trees had higher visitation density in the daytime. Zones with light devices, zones with more connected pathways, and zones without tables had higher visitation density at nighttime. These findings highlighted the seasonal and diurnal variation of the impacts of landscape features on park visitation and can help to improve urban park design, especially for cities with hot summers and cold winters.
通讯机构：
[Liu, F ] H;Hunan Agr Univ, Coll Hort, Engn Res Ctr, Key Lab Vegetable Biol Hunan Prov,Educ Minist,Germ, Changsha 410125, Peoples R China.;Hunan Univ, Longping Branch, Grad Sch, Changsha 410125, Hunan, Peoples R China.
关键词：
Pepper;Transcriptome;Flower development;Period-specific expression;Transcription factor;ABCDE model
摘要：
An analysis of genome-wide gene expression profiles during floral organ development can provide important clues about the molecular basis of gene functions and developmental processes. In this study, we analyzed the transcriptome data of 36 samples obtained during floral organ development from pepper ‘6421’ and detected 30 016 genes that were expressed in at least one sample. K-means clustering analysis was used to classify the data into 16 clusters based on the similarities between the dynamic expression profiles of genes. Of these, 15 clusters exhibited notable up-regulation or down-regulation trends in different developmental stages or tissues of floral organs. We identified transcription factors expressed at the early, medium, and late stages of bud development (F1, F5, F9). Transcription factor families such as AP2-ERF, MADS-box, MYB, bHLH, and NAC showed significant levels of enrichment. In comparison with genes expressed in vegetative tissues at different stages, certain genes were specifically up-regulated during flower development; among these, the number of genes specifically up-regulated during the stamen (Sta10) and bud tetrad development (F4) stages was the highest. Through extensive studies of the ABCDE model of flower development in Arabidopsis, we identified 17 ABCDE model candidate genes in pepper, most of which were up-regulated at specific stages of flower bud development. The expression data provided in this study is the most comprehensive dataset available for pepper to date and will serve as a resource for identifying the functions of many specific genes involved in flower development in pepper and other Solanaceae plants.
通讯机构：
[Li, XM ] H;Hunan Agr Univ, Coll Landscape Architecture & Art Design, Changsha 410128, Peoples R China.
关键词：
Percent green cover;Spatial heterogeneity;Driving factors;Urban greening
摘要：
Residential greenspace has great intracity variations. Its driving factors have been widely investigated in Western countries (e.g., in Europe and North America), where residential areas are mostly privately owned, but few studies have examined the determinants of residential greenspace in China, where land is owned by the gov-ernment. Taking the subtropical city of Changsha, China, as an example, this study mapped the percent green cover (PGC) in residential quarters with a fine-resolution satellite image. We also investigated its driving factors measured from multisource geospatial data. The results show that (1) the PGC in the residential quarters showed great spatial variation, with an average of 36.6% (0-85.7%) and a standard deviation of 18.3%. (2) Urban form, biophysical context, and socioeconomic factors together explained 49.18% of the variation in the PGC, and they independently explained 22.87%, 11.17%, and 2.31% of the variation, respectively. (3) Residential quarter size, PGC in the surrounding buffer zone, residential quarter age, housing value, and population density significantly and positively impact the PGC, while percent building cover, floor area ratio, and distance to city center had significant negative impacts. The strongest positive and negative impacts came from PGC in the surrounding buffer zone and percent building cover, respectively. Socioeconomic factors, the dominant driving factors in Western countries, show little impact on residential PGC. These findings expand our understanding of the intracity variation in greenspace coverage and the driving factors, which sheds light on the effective planning and management of urban greenspaces in China.
摘要：
Flesh color is a significant characteristic of watermelon. Although various flesh-color genes have been identified, the inheritance and molecular basis of the orange flesh trait remain relatively unexplored. In the present study, the genetic analysis of six generations derived from W1-1 (red flesh) and W1-61 (orange flesh) revealed that the orange flesh color trait was regulated by a single recessive gene, Clorf (orange flesh). Bulk segregant analysis (BSA) locked the range to ∼4.66 Mb, and initial mapping situated the Clorf locus within a 688.35-kb region of watermelon chromosome 10. Another 1,026 F(2) plants narrowed the Clorf locus to a 304.62-kb region containing 32 candidate genes. Subsequently, genome sequence variations in this 304.62-kb region were extracted for in silico BSA strategy among 11 resequenced lines (one orange flesh and ten nonorange flesh) and finally narrowed the Clorf locus into an 82.51-kb region containing nine candidate genes. Sequence variation analysis of coding regions and gene expression levels supports Cla97C10G200950 as the most possible candidate for Clorf, which encodes carotenoid isomerase (Crtiso). This study provides a genetic resource for investigating the orange flesh color of watermelon, with Clorf malfunction resulting in low lycopene accumulation and, thus, orange flesh.
摘要：
The protein levels in a diet are correlated with immunity but the long-term intake of excessive protein can compromise various aspects of health. L-theanine regulates immunity and protein metabolism; however, how its regulatory immunity effects under a high-protein diet are unclear. We used proteomics, metabonomics, and western blotting to analyze the effects of diets with different protein levels on immune function in rats to determine the role of L-theanine in immunity under a high-protein diet. The long-term intake of high-protein diets (>= 40% protein) promoted oxidative imbalance and inflammation. These were alleviated by L-theanine. High-protein diets inhibited peroxisome proliferator-activated receptor (PPAR)alpha expression through the inter-leukin (IL)-6/signal transducer and activator of transcription (STAT)3 pathway and mediated inflammation. L-theanine downregulated anti-fatty acid-binding protein 5 (FABP5), inhibited the IL-6/STAT3 axis, and reduced high-protein diet-induced PPAR alpha inhibition. Therefore, L-theanine alleviates the adverse effects of high-protein diets via the FABP5/IL-6/STAT3/PPAR alpha pathway and regulates the immunity of normally fed rats through the epoxide hydrolase (EPHX)2/nuclear factor-kappa B inhibitor (I kappa B)alpha/triggering receptor expressed on myeloid cells (TREM)1 axis.
摘要：
Obesity is regarded to be correlated with disorders of lipid metabolism, bile acid metabolism and dysbiosis of the gut microbiota. Moringa-Fu brick tea (MFBT), a functional food, has a significant anti-obesity effect. However, the effectiveness and mechanisms of MFBT in preventing obesity require further investigation. Here, our results show that moringa-Fu brick tea extract (MFTE) displays anti-obesity effects by reducing high-fat diet-induced weight gain and adipose tissue accumulation in rats, and attenuating visceral adiposity index, oxidative stress and inflammation. In addition, MFTE could regulate gut microbiota diversity, reduce the relative abundance of microbioa associated with bile salt hydrolase (BSH) activity, such as Blautia, Ruminococcaceae, Coprococcus and Roseburia. Moreover, MFTE could improve the expression of the main rate-limiting enzymes CYP7A1 and CYP27A1 in the process of bile acid synthesis, downregulate the expression of intestinal FXR protein, promote the serum bile acid level, and reduce the accumulation of cholesterol in serum and liver. Taken together, these results suggested that MFBT could serve as a functional food for prevention of obesity and hyperlipidemia in association with regulating bile acid metabolism and gut microbiota.
通讯机构：
[Qin Li] N;National Research Center of Engineering Technology for Utilization of Functional Ingredients from Botanicals, Hunan Agricultural University, Changsha 410128, China<&wdkj&>Collaborative Innovation Centre of Utilization of Functional Ingredients from Botanicals, Hunan Agricultural University, Changsha 410128, China<&wdkj&>Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
Sex determination in plants gives rise to unisexual flowers. A better understanding of the regulatory mechanism underlying the production of unisexual flowers will help to clarify the process of sex determination in plants and allow researchers and farmers to harness heterosis. Androecious cucumber (Cucumis sativus L.) plants can be used as the male parent when planted alongside a gynoecious line to produce heterozygous seeds, thus reducing the cost of seed production. The isolation and characterization of additional androecious genotypes in varied backgrounds will increase the pool of available germplasm for breeding. Here, we discovered an androecious mutant in a previously generated ethyl methanesulfonate (EMS)-mutagenized library of the cucumber inbred line '406'. Genetic analysis, whole-genome resequencing, and molecular marker-assisted verification demonstrated that a nonsynonymous mutation in the ethylene biosynthetic gene 1-AMINOCYCLOPROPANE-1-CARBOXYLATE SYNTHASE 11 (ACS11) conferred androecy. The mutation caused an amino acid change from serine (Ser) to phenylalanine (Phe) at position 301 (S301F). In vitro enzyme activity assays revealed that this S301F mutation leads to a complete loss of enzymatic activity. This study provides a new germplasm for use in cucumber breeding as the androecious male parent, and it offers new insights into the catalytic mechanism of ACS enzymes.
摘要：
Eurotium is the teleomorph genus associated with the section Aspergillus. Eurotium comprises approximately 20 species, which are widely distributed in nature and human environments. Eurotium is usually the key microorganism for the fermentation of traditional food, such as Fuzhuan brick tea, Liupao tea, Meju, and Karebushi; thus, Eurotium is an important fungus in the food industry. Eurotium has been extensively studied because it contains a series of interesting, structurally diverse, and biologically important secondary metabolites, including anthraquinones, benzaldehyde derivatives, and indol diketopiperazine alkaloids. These secondary metabolites have shown multiple biological activities, including antioxidative, antimicrobial, cytotoxic, antitumor, insecticidal, antimalarial, and anti-inflammatory activities. This study presents an up-to-date review of the phytochemistry and biological activities of all Eurotium species. This review will provide recent advances on the secondary metabolites and their bioactivities in the genus Eurotium for the first time and serve as a database for future research and drug development from the genus Eurotium.
通讯机构：
[Yang, S ; Ou, LJ] H;Hunan Agr Univ, Coll Hort, Engn Res Ctr Educ, Key Lab Vegetable Biol Hunan Prov,Minist Germplasm, Changsha 410125, Peoples R China.
摘要：
Light quality and intensity can have a significant impact on plant health and crop productivity. Chlorophylls and carotenoids are classes of plant pigments that are responsible for harvesting light energy and protecting plants from the damaging effects of intense light. Our understanding of the role played by plant pigments in light sensitivity has been aided by light-sensitive mutants that change colors upon exposure to light of variable intensity. In this study, we conducted transcriptomic, metabolomic, and hormone analyses on a novel yellowing mutant of pepper (yl1) to shed light on the molecular mechanism that regulates the transition from green to yellow leaves in this mutant upon exposure to high-intensity light. Our results revealed greater accumulation of the carotenoid precursor phytoene and the carotenoids phytofluene, antheraxanthin, and zeaxanthin in yl1 compared with wild-type plants under high light intensity. A transcriptomic analysis confirmed that enzymes involved in zeaxanthin and antheraxanthin biosynthesis were upregulated in yl1 upon exposure to high-intensity light. We also identified a single basic helix-loop-helix (bHLH) transcription factor, bHLH71-like, that was differentially expressed and positively correlated with light intensity in yl1. Silencing of bHLH71-like in pepper plants suppressed the yellowing phenotype and led to reduced accumulation of zeaxanthin and antheraxanthin. We propose that the yellow phenotype of yl1 induced by high light intensity could be caused by an increase in yellow carotenoid pigments, concurrent with a decrease in chlorophyll accumulation. Our results also suggest that bHLH71-like functions as a positive regulator of carotenoid biosynthesis in pepper.
