Emulsified sausages with yeast protein as an animal fat replacer: Effects on nutritional composition, spatial structure, gel performance, and sensory quality.

This paper investigated the effect of yeast protein (YP)-fat replacement on the nutritional composition, spatial structure, gel performance, and sensory quality of emulsified sausages. YP is enriched with essential amino acids (36.49 g/100 g), which improved the nutritional quality of sausages whereas reducing its fat content. Moreover, YP could absorb water and fat, thus the YP-added sausages exhibiting an amount-dependent increase in emulsion stability and water migration. The microstructure illustrated that YP acted as a filler to improve structural homogeneity and compactness of the pork gel network. And YP-fat replacement could significantly enhance the hardness, gel strength and elasticity of sausages whereas decreasing the viscosity. Additionally, at partial or full YP-fat replacement (25-100%), the YP-added sausages scored higher in odor and texture, as well as better antioxidant stability than controls. Overall, YP can be employed as a new fat substitute for the preparation of healthy and nutritional sausages, while maintaining the sensory quality.

A key mutation in magnesium chelatase I subunit leads to a chlorophyll-deficient mutant of tea (Camellia sinensis).

Tea (Camellia sinensis) is a highly important beverage crop renowned for its unique flavour and health benefits. Chlorotic mutants of tea, known worldwide for their umami taste and economic value, have gained global popularity. However, the genetic basis of this chlorosis trait remains unclear. In this study, we identified a major-effect quantitative trait locus (QTL), qChl-3, responsible for the chlorosis trait in tea leaves, linked to a non-synonymous polymorphism (G1199A) in the magnesium chelatase I subunit (CsCHLI). Homozygous CsCHLIA plants exhibited an albino phenotype due to defects in magnesium protoporphyrin IX and chlorophylls in the leaves. Biochemical assays revealed that CsCHLI mutations did not affect subcellular localization or interactions with CsCHLIG and CsCHLD. However, combining CsCHLIA with CsCHLIG significantly reduced ATPase activity. RNA-seq analysis tentatively indicated that CsCHLI inhibited photosynthesis and enhanced photoinhibition, which in turn promoted protein degradation and increased the amino acid levels in chlorotic leaves. RT-qPCR and enzyme activity assays confirmed the crucial role of asparagine synthetase and arginase in asparagine and arginine accumulation, with levels increasing over 90-fold in chlorotic leaves. Therefore, this study provides insights into the genetic mechanism underlying tea chlorosis and the relationship between chlorophyll biosynthesis and amino acid metabolism.

Allograft inflammatory factor-1 enhances inflammation and oxidative stress via the NF-κB pathway of bladder urothelium in diabetic rat model.

OBJECTIVES: To explore the role of allograft inflammatory factor-1 (AIF-1) both in diabetic rat bladder urothelium and in high-glucose-treated human urothelial cell line (SV-HUC-1). METHODS: Inflammation and oxidative stress (OS) promote diabetic cystopathy (DCP), but the mechanisms are not fully understood. The expression level of AIF-1 in diabetic rat bladder urothelium and in the SV-HUC-1 cells treated with high glucose was detected using tissue immunofluorescence, immunohistochemistry and western blot assays. AIF-1 was knocked down and NF-κB was suppressed with the specific inhibitor BAY 11-7082 in high-glucose-treated SV-HUC-1 cells. RESULTS: High-glucose condition induced AIF-1 upregulation in vivo and in vitro. The up-regulated AIF-1 induced the production of inflammatory factors IL-6 and TNF-α and elevation of ROS. Informatics analysis suggested that NF-κB pathway is implicated in DCP. Through knockdown of AIF-1, we confirmed that AIF-1 simulated NF-κB pathway by enhancing the phosphorylation of IκB (p-IκB) and promoting the translocation of NF-κB p65 from cytoplasm into nucleus. Additionally, High-glucose-induced inflammation in SV-HUC-1 cells was attenuated by the addition of NF-κB inhibitor. CONCLUSIONS: This study provides novel information to understand the molecular regulation mechanisms of AIF-1 in DCP.

Seascapes Shaped the Local Adaptation and Population Structure of South China Coast Yellowfin Seabream (Acanthopagrus latus).

Understanding the genetic composition and regional adaptation of marine species under environmental heterogeneity and fishing pressure is crucial for responsible management. In order to understand the genetic diversity and adaptability of yellowfin seabream (Acanthopagrus latus) along southern China coast, this study was conducted a seascape genome analysis on yellowfin seabream from the ecologically diverse coast, spanning over 1600 km. A total of 92 yellowfin seabream individuals from 15 sites were performed whole-genome resequencing, and 4,383,564 high-quality single nucleotide polymorphisms (SNPs) were called. By conducting a genotype-environment association analysis, 29,951 adaptive and 4,328,299 neutral SNPs were identified. The yellowfin seabream exhibited two distinct population structures, despite high gene flow between sites. The seascape genome analysis revealed that genetic structure was influenced by a variety of factors including salinity gradients, habitat distance, and ocean currents. The frequency of allelic variation at the candidate loci changed with the salinity gradient. Annotation of these loci revealed that most of the genes are associated with osmoregulation, such as kcnab2a, kcnk5a, and slc47a1. These genes are significantly enriched in pathways associated with ion transport including G protein-coupled receptor activity, transmembrane signaling receptor activity, and transporter activity. Overall, our findings provide insights into how seascape heterogeneity affects adaptive evolution, while providing important information for regional management in yellowfin seabream populations.

Gene mining and genomics-assisted breeding empowered by the pangenome of tea plant Camellia sinensis.

Tea is one of the world's oldest crops and is cultivated to produce beverages with various flavours. Despite advances in sequencing technologies, the genetic mechanisms underlying key agronomic traits of tea remain unclear. In this study, we present a high-quality pangenome of 22 elite cultivars, representing broad genetic diversity in the species. Our analysis reveals that a recent long terminal repeat burst contributed nearly 20% of gene copies, introducing functional genetic variants that affect phenotypes such as leaf colour. Our graphical pangenome improves the efficiency of genome-wide association studies and allows the identification of key genes controlling bud flush timing. We also identified strong correlations between allelic variants and flavour-related chemistries. These findings deepen our understanding of the genetic basis of tea quality and provide valuable genomic resources to facilitate its genomics-assisted breeding.

Transcriptome and Biochemical Analyses of a Chlorophyll-Deficient Bud Mutant of Tea Plant (Camellia sinensis).

Tea leaf-color mutants have attracted increasing attention due to their accumulation of quality-related biochemical components. However, there is limited understanding of the molecular mechanisms behind leaf-color bud mutation in tea plants. In this study, a chlorina tea shoot (HY) and a green tea shoot (LY) from the same tea plant were investigated using transcriptome and biochemical analyses. The results showed that the chlorophyll a, chlorophyll b, and total chlorophyll contents in the HY were significantly lower than the LY's, which might have been caused by the activation of several genes related to chlorophyll degradation, such as SGR and CLH. The down-regulation of the CHS, DFR, and ANS involved in flavonoid biosynthesis might result in the reduction in catechins, and the up-regulated GDHA and GS2 might bring about the accumulation of glutamate in HY. RT-qPCR assays of nine DEGs confirmed the RNA-seq results. Collectively, these findings provide insights into the molecular mechanism of the chlorophyll deficient-induced metabolic change in tea plants.

Impact of timing on protection of combined immunoprophylaxis in preventing mother-to-child transmission of hepatitis B virus: a retrospective study.

Objective: To evaluate the impact of timing combined immunoprophylaxis on mother-to-child transmission (MTCT) of the hepatitis B virus (HBV) in pregnant women living with hepatitis B. Methods: A retrospective cohort study was included HBsAg-positive pregnant women who delivered full-term at Tianjin Third Central Hospital from January 2019 to December 2021. The objective of this study is to determine whether early administration of hepatitis B immune globulin (HBIG) and the first dose of hepatitis B vaccination after birth can further improve protection. Result: A total of 694 pregnant women living with hepatitis B were included; 93 infants from these mothers were lost to follow-up [including moving (n = 21), emigrating (n = 26), changing contact information (n = 27), and other reasons (n = 19)], leaving 601 infants for analysis. The incidence in babies born to mothers with hepatitis B was 1.50% (9/601). Based on the different timing of combined immunoprophylaxis administration after birth, 601 infants were divided into two groups (within 2 h and within 2-12 h). The incidence in babies born to mothers with hepatitis B were 0.32% (1/308) and 2.73% (8/293) for infants who received combined immunoprophylaxis within 2 h and between 2 and 12 h of birth, respectively (p = 0.037). The infection incidence of infants born to HBeAg-positive mothers and HBeAg-positive mothers who did not receive antiviral treatment during pregnancy was lower in the 2-h group compared to the 2-12 h group (0.72% vs. 5.84%, p = 0.04 and 1.20% vs. 9.46%, p = 0.047). Conclusion: Using combined immunoprophylaxis as soon as possible (within two hours of birth) may protect against MTCT of HBV more.

Low-dose antimony exposure promotes prostate cancer proliferation by inhibiting ferroptosis via activation of the Nrf2-SLC7A11-GPX4 pathway.

Antimony (Sb) is a typical environmental pollutant. With the development of industrialization, antimony is widely used in daily life and enters the human body through the food chain, water source, air pollution, and other channels. The risk of antimony exposure has emerged as one of the public's major health concerns. Current research on antimony shows that antimony has certain biological toxicity, and antimony exposure may be one of the carcinogenic risk factors for bladder cancer, prostate cancer (PCa), and other cancers. But the molecular mechanism of antimony exposure in PCa is still unclear. Our results showed that serum antimony levels were significantly higher in PCa patients than in benign prostatic hyperplasia (BPH), and high levels of serum antimony were associated with poorer prognosis in PCa. We demonstrate that antimony exposure promotes PCa progression in vivo and in vitro. In addition, our results also showed that low-dose antimony exposure resulted in increased GSH, increased GPX4 expression, and decreased Fe2+. Since GPX4 and Fe2+ are important molecular features in the mechanism of ferroptosis, we further found that low-dose antimony exposure can inhibit RSL3-induced ferroptosis and promote PCa proliferation. Finally, our study demonstrates that low-dose antimony exposure promotes Nrf2 expression, increases the expression level of SLC7A11, and then increases the expression of GPX4, inhibits ferroptosis, and promotes PCa progression. Taken together, our experimental results suggest that low-dose antimony exposure promotes PCa cell proliferation by inhibiting ferroptosis through activation of the Nrf2-SLC7A11-GPX4 pathway. These findings highlight the link between low-dose antimony exposure and the Nrf2-SLC7A11-GPX4 ferroptosis pathway, providing a new potential direction for the prevention and treatment of PCa.

Simultaneous determination of protoporphyrin IX and magnesium protoporphyrin IX in Arabidopsis thaliana and Camellia sinensis using UPLC-MS/MS.

BACKGROUNDS: Insertion of Mg2+ into protoporphyrin IX (PPIX) to produce magnesium-protoporphyrin IX (Mg-PPIX) was the first step toward chlorophyll biosynthesis, which not only imparts plants green pigmentation but underpins photosynthesis. Plants that blocked the conversion of PPIX to Mg-PPIX displayed yellowish or albino-lethal phenotypes. However, the lack of systematic study of the detection method and the metabolic difference between species have caused the research on chloroplast retrograde signaling controversial for a long time. RESULTS: An advanced and sensitive UPLC-MS/MS strategy for determining PPIX and Mg-PPIX was established in two metabolic different plants, Arabidopsis thaliana (Columbia-0) and Camellia sinensis var. sinensis. Two metabolites could be extracted by 80% acetone (v/v) and 20% 0.1 M NH4OH (v/v) without hexane washing. Since the Mg-PPIX could be substantially de-metalized into PPIX in acidic conditions, analysis was carried out by UPLC-MS/MS with 0.1% ammonia (v/v) and 0.1% ammonium acetonitrile (v/v) as mobile phases using negative ion multiple reaction monitoring modes. Interestingly, it could be easier to monitor these two compounds in dehydrated samples rather than in fresh samples. Validation was performed in spiked samples and mean recoveries ranged from 70.5 to 916%, and the intra-day and inter-day variations were less than 7.5 and 10.9%, respectively. The limit of detection was 0.01 mg·kg- 1 and the limit of quantification was 0.05 mg·kg- 1. The contents of PPIX (1.67 ± 0.12 mg·kg- 1) and Mg-PPIX (3.37 ± 0.10 mg·kg- 1) in tea were significantly higher than in Arabidopsis (PPIX: 0.05 ± 0.02 mg·kg- 1; Mg-PPIX: 0.08 ± 0.01 mg·kg- 1) and they were only detected in the leaf. CONCLUSIONS: Our study establishes a universal and reliable method for determining PPIX and Mg-PPIX in two plants using UPLC-MS/MS. This procedure will facilitate studying chlorophyll metabolism and natural chlorophyll production.

The potential effects of chlorophyll-deficient mutation and tree_age on the accumulation of amino acid components in tea plants.

Albino tea has been receiving growing attention on the tea market due to its attractive appearance and fresh taste, mainly caused by high amino acid contents. Here, variations in the contents of five free amino acids in relation to pigment contents and tree age in two hybrid populations'Longjin 43'(♀) × 'Baijiguan'(♂) and 'Longjin 43'(♀) ×'Huangjinya'(♂) with 334 first filial generation individuals including chlorophyll-deficient and normal tea plants were investigated. The data showed that the contents of main amino acids in all filial generation gradually decreased as plant age increased. Principal component analysis indicated that the amino acid content of individual plant tended to be stable with the growth of plants. Correlation analysis clarified that several main amino acids were significantly negatively correlated with chlorophyll a, chlorophyll b and carotenoid contents. Our results showed that the accumulation of amino acids in tea plant was closely related to leaf color variation and the tree age during growing period.

Quantitative trait loci mapping for free amino acid content using an albino population and SNP markers provides insight into the genetic improvement of tea plants.

Free amino acids are one of the main chemical components in tea, and they contribute to the pleasant flavor, function, and quality of tea, notably the level of theanine. Here, a high-density genetic map was constructed to characterize quantitative trait loci (QTLs) for free amino acid content. A total of 2688 polymorphic SNP markers were obtained using genotyping-by-sequencing (GBS) based on 198 individuals derived from a pseudotestcross population of "Longjing 43" × "Baijiguan", which are elite and albino tea cultivars, respectively. The 1846.32 cM high-density map with an average interval of 0.69 cM was successfully divided into 15 linkage groups (LGs) ranging from 93.41 cM to 171.28 cM. Furthermore, a total of 4 QTLs related to free amino acid content (theanine, glutamate, glutamine, aspartic acid and arginine) identified over two years were mapped to LG03, LG06, LG11 and LG14. The phenotypic variation explained by these QTLs ranged from 11.8% to 23.7%, with an LOD score from 3.56 to 7.7. Furthermore, several important amino acid metabolic pathways were enriched based on the upregulated differentially expressed genes (DEGs) among the offspring. These results will be essential for fine mapping genes involved in amino acid pathways and diversity, thereby providing a promising avenue for the genetic improvement of tea plants.

Multiple fluorescence quenching effects mediated fluorescent sensing of captopril Based on amino Acids-Derivative carbon nanodots.

Carbon nanodots (CNDs) were facilely synthesized through a pyrolysis procedure with histamine, an amino acid rich in element carbon and nitrogen, being the precursor. Taking advantage of the favorable fluorescence performance of CNDs, a multiple fluorescence quenching effects mediated fluorescent sensor was established for captopril (CAP) detection. MnO2 NPs were firstly combined with CNDs via electrostatic attraction and subsequently quenched the fluorescence. The quenching mechanisms were concluded to be the combined effects of fluorescence resonance energy transfer (FRET) and inner filtration effect (IFE). Subsequently CAP triggered a unique redox reaction and decomposed the quencher so that renewed the fluorescence. Hence, the sensitive and selective detection of CAP was achieved through the indication of fluorescence recovery efficiency. A proportional range of 0.4 âˆ¼ 60 µmol L-1 with the LOD of 0.31 µmol L-1 was obtained. The sensor was further applied to the real sample detection and the satisfactory results revealed the practical value of CNDs. The facile synthesis of CNDs and brand-new sensing mechanism made it a novel fluorescent method and could improve the analysis of CAP.

Transcriptomic and Metabolomic Analyses Provide Insights Into an Aberrant Tissue of Tea Plant (Camellia sinensis).

Tea plant (Camellia sinensis (L.) O. Kuntze) is one of the most important economic crops with multiple mutants. Recently, we found a special tea germplasm that has an aberrant tissue on its branches. To figure out whether this aberrant tissue is associated with floral bud (FB) or dormant bud (DB), we performed tissue section, transcriptome sequencing, and metabolomic analysis of these tissues. Longitudinal sections indicated the aberrant tissue internal structure was more like a special bud (SB), but was similar to that of DB. Transcriptome data analysis showed that the number of heterozygous and homozygous SNPs was significantly different in the aberrant tissue compared with FB and DB. Further, by aligning the unmapped sequences of the aberrant tissue to the Non-Redundant Protein Sequences (NR) database, we observed that 36.13% of unmapped sequences were insect sequences, which suggested that the aberrant tissue might be a variation of dormant bud tissue influenced by the interaction of tea plants and insects or pathogens. Metabolomic analysis showed that the differentially expressed metabolites (DEMs) between the aberrant tissue and DB were significantly enriched in the metabolic pathways of biosynthesis of plant hormones and biosynthesis of phenylpropanoids. Subsequently, we analyzed the differentially expressed genes (DEGs) in the above mentioned two tissues, and the results indicated that photosynthetic capacity in the aberrant tissue was reduced, whereas the ethylene, salicylic acid and jasmonic acid signaling pathways were activated. We speculated that exogenous infection induced programmed cell death (PCD) and increased the lignin content in dormant buds of tea plants, leading to the formation of this aberrant tissue. This study advanced our understanding of the interaction between plants and insects or pathogens, providing important clues about biotic stress factors and key genes that lead to mutations and formation of the aberrant tissue.

Functional Status of Pancreatic α and ß Cells in Type 2 Diabetes Mellitus Patients with Different Plasma Triglyceride Levels: A Retrospective Analysis.

OBJECTIVE: To investigate the functional status of pancreatic α and ß cells in Type 2 diabetes mellitus (T2DM) patients with different plasma triglyceride (TG) levels. TG levels can be prognostic markers for T2DM. METHODS: A total of 328 patients with T2DM were divided into three groups according to different TG levels: the TGL group: TG < 1.7 mmol/L; TGM group: 1.7 mmol/L ≤ TG < 2.3 mmol/L; and TGH group: TG ≥ 2.3 mmol/L. An oral glucose tolerance test (OGTT), insulin release test, and glucagon release test were performed in each patient. The changes of glucagon, glucagon/insulin ratio, early insulin secretion index (ΔI 30/ΔG 30), and area under the insulin curve (AUCI) were compared among each group. Also, the correlations between glucagon and pancreatic ß-cell function, glycosylated hemoglobin (HbA1c), and other indices were analyzed. RESULTS: With the increase of TG, the fasting and postprandial glucagon levels, the glucagon/insulin ratio, and the area under the glucagon curve (AUCG) presented an increasing trend. The homeostasis model assessment of insulin resistance (HOMA-IR) of the TGH group was significantly increased compared to the TGL and TGM groups. In addition to the increase in TG levels, the insulin sensitivity index (ISI), homeostasis model assessment for ß-cell function index (HOMA-ß), ΔI 30/ΔG 30, and AUCI displayed a reducing trend. Glucagon was negatively correlated with ΔI 30/ΔG 30, high-density lipoprotein (HDL), HOMA-ß, body mass index (BMI), ISI, and AUCI (P < 0.05) and positively correlated with fasting blood glucose (FPG), AUCG, HOMA-IR, HbA1c, duration, TG, low-density lipoprotein (LDL), and total cholesterol (TC) (P < 0.05). CONCLUSION: Hypertriglyceridemia aggravated the dysfunction of pancreatic α and ß cells. A reasonable control of the TG level makes it easier for blood glucose to reach the standard.

Antimony exposure promotes bladder tumor cell growth by inhibiting PINK1-Parkin-mediated mitophagy.

Antimony is one of the heavier pnictogens and is widely found in human food chains, water sources, and as an air pollutant. Recent years have seen steadily increasing concentrations of antimony in the ecological environment; critically, several studies have indicated that antimony might pose a tumorigenic risk factor in several cancers. Therefore, antimony toxicity has attracted increasing research attention, with the molecular mechanisms underlying suspected antimony-mediated tumor transformation of greatest interest. Our results showed that the serum concentration of antimony was higher in bladder tumor patients relative to levels in non-tumor patients. Moreover, that such high antimony serum concentration were closely associated with poorer outcome in bladder tumor patients. Additionally, we demonstrated that the presence of antimony promoted both in vitro and in vivo bladder tumor cell growth. Our results also indicated that low-dose antimony resulted in significantly decreased mitochondrial membrane potential, mitochondrial respiratory enzyme complex I/II/III/IV activity, ATP/ADP ratio, and ATP concentration relative to the control group. These findings suggested that antimony caused mitochondrial damage. Finally, we found that low-dose antimony(0.8uM) inhibited mitophagy by deregulating expression of PINK1, Parkin, and p(ser65)-Parkin, and activation of PINK1-Parkin pathway by CCCP could inhibit antimony-induced tumor cell growth. Collectively, this inhibited the proliferation of bladder tumor cells. Overall, our study suggested that antimony promoted bladder tumor cell growth by inhibiting PINK1-Parkin-mediated mitophagy. These findings highlight the therapeutic potential in targeting molecules within this antimony induced-PINK1/Parkin signaling pathway and may offer a new approach for the treatment of bladder cancer.

Assessing responses of phytoplankton to consecutive typhoons by combining Argo, remote sensing and numerical simulation data.

Typhoons can affect various hydrodynamic processes, such as upwelling, vertical mixing, and entrainment, which in turn influence the growth and redistribution of phytoplankton. In this study, responses of phytoplankton to consecutive typhoons Barijat and Mangkhut in summer 2018 in the northern South China Sea (NSCS) were investigated through combining remote sensing, numerical simulation, and Argo profile data. Variations of physical and biological properties induced by Barijat and Mangkhut over the study region were observed. Regional chlorophyll-a (Chla) algorithms over the NSCS were assessed in order to accurately quantify typhoon-induced variations of phytoplankton. Chla concentration decreased slightly over the region of interest after the passage of Barijiat while increased obviously after the passage of Mangkhut. Satellite-derived Chla increased by ~63% on average after the consecutive typhoons. Responses of phytoplankton size structure (PSS) were further investigated over the continental shelf and the deep ocean in the NSCS. For the continental shelf, the increment of micro- and nano-phytoplankton was about 1.5-fold as high as that of pico-phytoplankton, compared with a 0.5-fold increment for the deep ocean. This study attested the discrepant responses of different phytoplankton size classes to typhoons. It was of great significance to expand our understanding of ocean physical and ecological responses to extreme phenomena. Our finding underscores the potential of remote sensing to investigate typhoon-induced variation of PSS and could be the key to accurately assess typhoon-induced carbon fluxes, primary production, and potential fishing ground in the future.

Population sequencing enhances understanding of tea plant evolution.

Tea is an economically important plant characterized by a large genome, high heterozygosity, and high species diversity. In this study, we assemble a 3.26-Gb high-quality chromosome-scale genome for the 'Longjing 43' cultivar of Camellia sinensis var. sinensis. Genomic resequencing of 139 tea accessions from around the world is used to investigate the evolution and phylogenetic relationships of tea accessions. We find that hybridization has increased the heterozygosity and wide-ranging gene flow among tea populations with the spread of tea cultivation. Population genetic and transcriptomic analyses reveal that during domestication, selection for disease resistance and flavor in C. sinensis var. sinensis populations has been stronger than that in C. sinensis var. assamica populations. This study provides resources for marker-assisted breeding of tea and sets the foundation for further research on tea genetics and evolution.

Identifying Conserved Functional Gene Modules Underlying the Dynamic Regulation of Tea Plant Development and Secondary Metabolism.

Tea plants adjust development and metabolism by integrating environmental and endogenous signals in complex but poorly defined gene networks. Here, we present an integrative analysis framework for the identification of conserved modules controlling important agronomic traits using a comprehensive collection of RNA-seq datasets in Camellia plants including 189 samples. In total, 212 secondary metabolism-, 182 stress response-, and 182 tissue development-related coexpressed modules were revealed. Functional modules (e.g., drought response, theobromine biosynthesis, and new shoot development-related modules) and potential regulators that were highly conserved across diverse genetic backgrounds and/or environmental conditions were then identified by cross-experiment comparisons and consensus clustering. Moreover, we investigate the preservation of gene networks between Camellia sinensis and other Camellia species. This revealed that the coexpression patterns of several recently evolved modules related to secondary metabolism and environmental adaptation were rewired and showed higher connectivity in tea plants. These conserved modules are excellent candidates for modeling the core mechanism of tea plant development and secondary metabolism and should serve as a great resource for hypothesis generation and tea quality improvement.

Repressed Gene Expression of Photosynthetic Antenna Proteins Associated with Yellow Leaf Variation as Revealed by Bulked Segregant RNA-seq in Tea Plant Camellia sinensis.

The young leaves and shoots of albino tea cultivars are usually characterized as having a yellow or pale color, high amino acid, and low catechin. Increasing attention has been paid to albino tea cultivars in recent years because their tea generally shows high umami and reduced astringency. However, the genetic mechanism of yellow-leaf variation in albino tea cultivar has not been elucidated clearly. In this study, bulked segregant RNA-seq (BSR-seq) was performed on bulked yellow- and green-leaf hybrid progenies from a leaf color variation population. A total of 359 and 1134 differentially expressed genes (DEGs) were identified in the yellow and green hybrid bulked groups (Yf vs Gf) and parent plants (Yp vs Gp), respectively. The significantly smaller number of DEGs in Yf versus Gf than in Yp versus Gp indicated that individual differences could be reduced within the same hybrid progeny. Analysis of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes revealed that the photosynthetic antenna protein was most significantly enriched in either the bulked groups or their parents. Interaction was found among light-harvesting chlorophyll a/b -binding proteins (LHC), heat shock proteins (HSPs), and enzymes involved in cuticle formation. Combined with the transcriptomic expression profile, results showed that the repressed genes encoding LHC were closely linked to aberrant chloroplast development in yellow-leaf tea plants. Furthermore, the photoprotection and light stress response possessed by genes involved in HSP protein interaction and cuticle formation were discussed. The expression profile of DEGs was verified via quantitative real-time PCR analysis of the bulked samples and other F1 individuals. In summary, using BSR-seq on a hybrid population eliminated certain disturbing effects of genetic background and individual discrepancy, thereby helping this study to intensively focus on the key genes controlling leaf color variation in yellow-leaf tea plants.