Pitaya is a tropical and subtropical fruit; it can produce several batches fruit in one year. To find out the fruit quality differences between various batches in the same year in Guangzhou, South China, 11 pitaya varieties were used as the materials. Comparative analysis was performed between these varieties of each batch by 14 indexes, comprehensive evaluation and ranking were evaluated by the principal component analysis (PCA). Results showed that the red-peel and red-pulp pitaya has the longer fruit period and could obtain more batches fruits. By comparing the fruit quality of these 11 varieties in different batches: Except "Guanhuahong," fruit weight is significant different between other 10 varieties. The edible rate of fruits from 2(nd) and 3(rd) batches is significantly higher than others. The hardness, total sugar, total acid, betalain, total phenol, and flavonoids were significant difference between batches. The PCA results indicated that in most varieties, the 1(st), 8(th), 9(th) batches are generally with heavier fruit, better color, harder and sweeter; more stable antioxidant compounds were shown in 6(th), 7(th), 8(th), 9(th) batches; the 3(rd), 4(th), 5(th), and 6(th) batches are smaller, softer, lower soluble sugar and higher titratable acid. Pitaya fruit quality and tastes from various batches are different in the same year, the climate may be the main factor. The fruits of 7(th), 8(th) and 9(th) batches picking from Sep to Nov has better quality and higher economic value. This research has practical application value and could provide theoretical basis for the production of pitaya.

Anthocyanin is a natural plant pigment whose biosynthesis is intricately linked to light regulation. Here, pericarps of red mango cultivars named 'Xinshiji (XSJ)' and 'Hongmang No.6 (HM6)' directly exposed to sunlight were red while they were green under shade conditions, whereas the pericarps of green mango cultivar known as 'Guiqi (GQ)' maintained green within both light and shade conditions. However, the mechanisms underlying these color changes under different light conditions remain largely unexplored. Therefore, we analyzed the contents, components, and biosynthesis of anthocyanins in the above mango pericarps through metabolome and transcriptome analyses. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis releaved a total of 35 anthocyanin compounds were detected in the mango pericarps. Transcriptome analysis uncovered 44 differentially expressed genes among the comparison of 'XSJ', 'HM6', and 'GQ' samples. Twelve and eight candidate genes were identified in the anthocyanin biosynthesis and chlorophyll breakdown pathways, respectively. A co-expression network of the key anthocyanin biosynthetic genes revealed that twelve transcription factors may govern anthocyanin biosynthesis and chlorophyll breakdown processes under light. These candidate genes were further verified by real-time quantitative PCR (RT-qPCR) for providing a regulatory model for the formation of red-and green-pericarps in mangoes under light and shade conditions. These results deepen our understanding of light-induced anthocyanin biosynthesis in fruits.

The CONSTANS/CONSTANS-Like (CO/COL) family has been shown to play important roles in flowering, stress tolerance, fruit development and ripening in higher plants. In this study, three COL genes, MiCOL6, MiCOL7A and MiCOL7B, which each contain only one CCT domain, were isolated from mango (Mangifera indica), and their functions were investigated. MiCOL7A and MiCOL7B were expressed mainly at 20 days after flowering (DAF), and all three genes were highly expressed during the flowering induction period. The expression levels of the three genes were affected by light conditions, but only MiCOL6 exhibited a clear circadian rhythm. Overexpression of MiCOL6 promoted earlier flowering, while overexpression of MiCOL7A or MiCOL7B delayed flowering compared to that in the control lines of Arabidopsis thaliana under long-day (LD) and short-day (SD) conditions. Overexpressing MiCOL6, MiCOL7A or MiCOL7B in transgenic plants increased superoxide dismutase (SOD) and proline levels, decreased malondialdehyde (MAD) levels, and improved survival under drought and salt stress. In addition, yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) analyses showed that the MiCOL6, MiCOL7A and MiCOL7B proteins interact with several stress- and flower-related proteins. This work demonstrates the functions of MiCOL6, MiCOL7A and MiCOL7B and provides a foundation for further research on the role of mango COL genes in flowering regulation and the abiotic stress response.

Objectives Myeloblastosis (MYB) proteins, recognized as crucial transcriptional regulators, play an integral role in orchestrating the range of plant colors.Materials and Methods Pitaya (Hylocereus spp.), a distinctive commercially cultivated fruit, stands apart due to its unique betalains, water-soluble nitrogen-enriched pigments that confer its vibrant hues. Although betalain biosynthesis has been extensively explored, the potential influence of co-activators that might disrupt pigment production remains relatively unexplored.Results In this study, we found that HuMYB9, an R2R3-MYB repressor, exhibited a remarkable decreasing during pitaya maturation. Sequence alignment analyses showed conserved R2 and R3 domains within the C-terminal of HuMYB9. HuMYB9's regulatory activities were found to be nuclear localized and it interacted with specific elements within the promoters of HuDODA1, HuADH1, and HuCYP76AD1-1, thus influencing the transcriptional activities in vitro. HuMYB9 transiently downregulated the expression of key betalain biosynthetic genes with a corresponding effect on the levels of pitaya pulp betalains.Conclusions Our results suggest that HuMYB9 operates as a suppressor, specifically downregulating the expression of HuCYP76AD1-1, HuDODA1, and HuADH, thereby modulating betalain biosynthesis in pitaya. Collectively, our findings provide invaluable insights into the regulation of betalain accumulation in pitaya.

Thidiazuron (TDZ) is used for the expansion of fruits, but excessive levels of TDZ lead to a decline in fruit quality. The appropriate concentration of TDZ for mango expansion without a decline in quality is not clear. In the present study, four different concentrations (5, 10, 15, and 20 mg/L) of TDZ were applied via spraying on mango plants, and several physiological and biochemical indicators were measured. The results showed that TDZ treatment significantly increased mango fruit size and single-fruit weight. In mango fruit, TDZ treatment decreased the disease index, delayed the increase in the malondialdehyde and H2O2 content, and maintained firmness and antioxidant capacities at a relatively high level during postharvest storage. At the same time, TDZ treatment delayed the decrease in the giberellin, indoleacetic acid and jasmonic acid content in mango, and reduced the accumulation of abscisic acid and ethylene. These trends are consistent with TDZ treatment leading to extension of the shelf life of mango. Furthermore, ethylene biosynthesis, signal transduction, and cell wall dismantling-related genes were investigated. The results indicated that the expression of the MiACS, MiETR2, MiERF113, MiERF010, MiERF054, MiEXP, MiPG14, MiPG21, MiCEL, and MiPEL genes in mango was inhibited under TDZ treatment compared with the control. In summary, TDZ treatment can significantly increase the size and weight of mango fruit and can extend its shelf life. The most suitable concentration is 10-15 mg/L TDZ, which will not affect the quality of mango fruit.

木棉成为岭南的象征并非一蹴而就,其文化地位的确立主要是在明代之后.陈恭尹为木棉塑造的英雄形象,因其符合大众的审美期待而受到后世的接受和认同.木棉能够加冕南花之王,主要得益于文人对南海神祠前木棉古树的群体性题咏.祝融意象的参与让南海神庙的木棉获得一种地域象征的地位,也形塑了后人对木棉作为南花之王的普遍记忆.近现代的市花评选更是将木棉的英雄形象与革命话语相结合,不仅巩固了木棉的文化地位,而且拓展它的象征意义.

为了探究不同时间采摘的火龙果果实品质之间的差异,以红皮红肉"红冠1号""红冠2号""湛江红肉""49-3""莞华红""红水晶"、红皮白肉"莞华白""红宝石""阳西白肉"、红皮粉红肉"莞华红粉"和红皮双色肉"双色1号"11个火龙果品种为材料,测定分析不同批次采摘的果实品质.结果表明,红肉品种一年内结果批次比其他品种多,产果期更长.同一品种果实单个品质指标不同批次间基本都存在显著性差异,综合比较发现,11个品种的第7、8、9批次果实的综合品质普遍较好,第3、4、5、6批次果实综合品质普遍稍差.说明火龙果一年间不同批次果实品质上存在显著性差异,可通过栽培技术调节来满足市场需求.

The SQUAMOSA promoter binding protein-like (SPL) gene family is a unique family of plant-specific transcription factors (TFs), which plays vital roles in a variety of plant biological processes. Its role in betalain biosynthesis in Hylocereus undantus; however, is still unclear. Here, we report a total of 16 HuSPL genes from the pitaya genome, which were unevenly distributed among nine chromosomes. The HuSPL genes were clustered into seven groups, and most HuSPLs within the same group shared similar exon-intron structures and conserved motifs. Eight segment replication events in the HuSPL gene family were the main driving force behind the gene family expansion. Nine of the HuSPL genes had potential target sites for Hmo-miR156/157b. Hmo-miR156/157b-targeted HuSPLs exhibited differential expression patterns compared with constitutive expression patterns of most Hmo-miR156/157b-nontargeted HuSPLs. The expression of Hmo-miR156/157b gradually increased during fruit maturation, while the expression of Hmo-miR156/157b-targeted HuSPL5/11/14 gradually decreased. In addition, the lowest expression level of Hmo-miR156/157b-targeted HuSPL12 was detected 23rd day after flowering, when the middle pulps started to turn red. HuSPL5, HuSPL11, HuSPL12, and HuSPL14 were nucleus-localized proteins. HuSPL12 could inhibit the expression of HuWRKY40 by binding to its promoter. Results from yeast two-hybrid and bimolecular fluorescence complementation assays showed that HuSPL12 could interact with HuMYB1, HuMYB132, or HuWRKY42 TFs responsible for betalain biosynthesis. The results of the present study provide an essential basis for future regulation of betalain accumulation in pitaya.

BACKGROUND:Multiple MYB transcription factors (TFs) are involved in the regulation of plant coloring. Betalain is a kind of natural plant pigment and its biosynthesis is regulated by a number of enzymes. Despite this, little is known about the molecular properties and roles of MYB TFs in pitaya betalain biosynthesis.RESULTS:In the present study, we identified a 1R-MYB gene, HuMYB132, which is preferentially expressed in red-pulp pitaya at the mature stage. It was clustered with Arabidopsis R-R-type genes and had two DNA-binding domains and a histidine-rich region. The expression assays in N. benthamiana and yeast indicated that HuMYB132 is a nucleus-localized protein with transcriptional activation activity. Dual luciferase reporter assay and electrophoretic mobility shift assays (EMSA) demonstrated that HuMYB132 could promote the transcriptional activities of HuADH1, HuCYP76AD1-1, and HuDODA1 by binding to their promoters. Silencing HuMYB132 reduced betalain accumulation and the expression levels of betalain biosynthetic genes in pitaya pulps.CONCLUSIONS:According to our findings, HuMYB132, a R-R type member of 1R-MYB TF subfamily, positively regulates pitaya betalain biosynthesis by regulating the expression of HuADH1, HuCYP76AD1-1, and HuDODA1. The present study provides a new theoretical reference for the management of pitaya betalain biosynthesis and also provides an essential basis for future regulation of betalain biosynthesis in Hylocereus.

Basic helix-loop-helix (bHLH) proteins are dimeric transcription factors (TFs) involved in various plant physi-ological and biological processes. Despite this, little is known about the molecular properties and roles of bHLH TFs in pitaya betalain biosynthesis. Here we report the identification of 165 HubHLH genes in H. undantus genome, their chromosomal distribution, physiochemical characteristics, conserved motifs, gene structure, phylogeny and synteny of HubHLH genes. Based on phylogenetic relationship analysis, the 165 HubHLHs were divided into 26 subfamilies and unequally distributed on the 11 chromosomes of pitaya. Based on the pitaya transcriptome data, a candidate gene HubHLH159 was obtained, and the real-time quantitative PCR analysis confirmed that HubHLH159 showed a high expression level in 'Guanhuahong' pitaya (red-pulp) at mature stage, indicating its role in betalain biosynthesis. HubHLH159 is a Group II protein and contains a bHLH domain. It is a nuclear protein with transcriptional activation activity. Dual luciferase reporter assays and virus-induced gene silencing (VIGS) experiments showed that HubHLH159 promotes betalain biosynthesis by activating the expression of HuADH1, HuCYP76AD1-1, and HuDODA1. The results of the present study lay a new theoretical reference for the regulation of pitaya betalain biosynthesis and also provides as essential basis for the future analysis of the functions of HubHLH gene family.

The WRKY gene family is a plant-specific transcription factor (TF) that regulates many physiological processes and (a) biotic stress responses. Despite this, little is known about the molecular properties and roles of WRKY TFs in pitaya betalain biosynthesis. Here we report the identification of 70 WRKY in Hylocereus undatus, their gene structure, locations on each chromosome, systematic phylogenetic analysis, conserved motif analysis, and synteny of HuWRKY genes. HmoWRKY42 is a Group IIb WRKY protein and contains a coiled-coil motif, a WRKY domain and a C2H2 zinc-finger motif (CX5CX23HXH). Results from yeast one-hybrid and transient dual-luciferase assays showed that HmoWRKY42 was a transcriptional repressor and could repress HmocDOPA5GT1 expression by binding to its promoter. Yeast two-hybrid assays showed that HmoWRKY42 could interact with itself to form homodimers. Knocking out the coiled-coil motif of HmoWRKY42 prevented its self-interaction and prevented it from binding to the HmocDOPA5GT1 promoter. Knocking out the WRKY domain and C2H2 zinc-finger motif sequence of HmoWRKY42 also prevented it from binding to the HmocDOPA5GT1 promoter. The coiled-coil motif, the WRKY domain and the C2H2 zinc finger motif are key motifs for the binding of HmoWRKY42 to the HmocDOPA5GT1 promoter. HmoWRKY42 is localized in the nucleus and possesses trans-activation ability responsible for pitaya betalain biosynthesis by repressing the transcription of HmocDOPA5GT1. As far as we know, no reports are available on the role of HmoWRKY42 in pitaya betalain biosynthesis. The results provide an important foundation for future analyses of the regulation and functions of the HuWRKY gene family.

Sugar and organic acids are important factors determining pitaya fruit quality. However, changes in sugars and acids, and expressions of metabolism-associated genes during fruit maturation of yellow-peel pitayas are not well-documented. In this study, metabolic and expression analyses in pulps of different fruit developmental stages of 'Wucihuanglong' ('WCHL', Hylocereus undatus) and 'Youcihuanglong' pitaya ('YCHL', Hylocereus megalanthus) were used to explore the sugar and organic acid metabolic process. Total phenols and flavonoids were mainly accumulated at S1 in pitaya pulps. Ascorbic acid contents of 'WCHL' pitaya were higher than that of 'YCHL' pitaya during fruit maturation. Starch was mainly accumulated at early fruit development stages while soluble sugars were rich in late stages. Sucrose, fructose, and glucose were the main sugar components of 'YCHL' pitaya while glucose was dominant in 'WCHL' pitaya. Malic and citric acids were the main organic acids in 'WCHL' and 'YCHL' pitayas, respectively. Based on the transcriptome analyses, 118 genes involved in pitaya sugar and organic acid metabolism were obtained. Results from the correlation analyses between the expression profiling of candidate genes and the contents of sugar and organic acid showed that 51 genes had a significant correlation relationship and probably perform key role in pitaya sugar and organic acid metabolism processes. The finding of the present study provides new information for quality regulation of pitayas.

清代可考的朱彝尊诗注共有十六种,注者群体以嘉兴府士人(同里后学)为主.诗注的编纂和刊刻主要受社会风气、士人趣味、文本的地域性、注本的象征性等方面影响和推动.流传最广的江浩然、杨谦、孙银槎三家注本以及新发现的李富孙批语过录本在文献的层累中不断更新,其递进关系可以给未来的汇注指明方向,其开放性则昭示着再生产过程的循环往复."诗注再生产"是文学史上颇为普遍的现象,其机制、策略、过程虽然各有不同,但都能由此扩大文集影响力,成为作家经典化的重要一环.

Pitaya (Selenicereus) is a kind of novel fruit with a delicious taste and superior horticulture ornamental value. The potential economic impact of the pitaya lies in its diverse uses not only as agricultural produce and processed foods but also in industrial and medicinal products. It is also an excellent plant material for basic and applied biological research. A comprehensive database of pitaya would facilitate studies of pitaya and the other Cactaceae plant species. Here, we constructed pitaya genome and multiomics database, which is a collection of the most updated and high-quality pitaya genomic assemblies. The database contains various information such as genomic variation, gene expression, miRNA profiles, metabolite and proteomic data from various tissues and fruit developmental stages of different pitaya cultivars. In PGMD, we also uploaded videos on the flowering process and planting tutorials for practical usage of pitaya. Overall, these valuable data provided in the PGMD will significantly facilitate future studies on population genetics, molecular breeding and function research of pitaya.

Sugar composition not only affects fruit flavor but is also an important determinant of fruit taste and consumer preference. In this study, changes in the sugar content and sugar-metabolizing enzymes were investigated from different sections of various fruit development phases of 'Hongshuijing' pitaya (Hylocereus monacanthus). Genes related to sugar metabolism were also screened by transcriptome analyses. The results indicated that glucose was the major sugar in mature pitaya fruit, and was mainly regulated by vacuolar acid invertase (VAI) and sucrose synthase (SS) (degradative direction). Sugar accumulation varied in pulp between different sections of the pitaya fruit. VAI, neutral invertase (NI) and SS (degradative direction) are crucial enzymes for sugar accumulation in pitaya. The expression of 17 genes related to sucrose metabolism obtained from seven databases [NCBI non-redundant protein database (Nr), NCBI non-redundant nucleotide sequence database (Nt), EuKaryotic Orthologous Groups (KOG), The Protein Families (Pfam), Kyoto Encyclopedia of Genes and Genomes (KEGG), Swiss-prot, and Gene Ontology (GO)] were analyzed in different pitaya pulp sections. HpVAI1 had the highest relative expression level on the 29th day after pollination (DAP). Positive correlations were found between HpVAI1 expression and VAI activity; HpNI4 and NI activity; HpSS2, HpSS5, and SS activity (synthetic direction), indicating that HpVAI1, HpNI4, and HpSS2 and HpSS5 were involved in the regulation of VAI, NI, and SS (synthetic direction), respectively. HpVAI1 and HpNI4 regulated sucrose degradation and the accumulation of glucose and fructose, while HpSS2 and HpSS5 regulated sucrose synthesis. These results suggest that HpVAI1 plays a key role in sugar metabolism during fruit development of 'Hongshuijing' pitaya. The results of this study provide new information about sugar metabolism in pitaya fruit that could help improve fruit quality and the breeding of new cultivars.

宋前文献中,碑刻碑文的利用和归类隐含了方志中金石类编纂的两个传统.一个是引碑证地的考据传统,一个是金石文字的编集传统.宋代方志多设有"碑碣"一门,其设置时间最早可上推到大中祥符三年(1010),而真正冠以"金石"之名,且做到名实相副,则要晚至清代.明代方志普遍将金石文字纳入艺文志中,体现了金石文字的编集传统,却中断了宋元的考据传统.清代学者受到金石学研究风气的影响,重新确立方志中金石类的独立地位,并引入录文兼考证的编写体例,体现出清代方志金石类的新变化.

Pitaya (Hylocereus) is the most economically important fleshy-fruited tree of the Cactaceae family that is grown worldwide, and it has attracted significant attention because of its betalain-abundant fruits. Nonetheless, the lack of a pitaya reference genome significantly hinders studies focused on its evolution, as well as the potential for genetic improvement of this crop. Herein, we employed various sequencing approaches, namely, PacBio-SMRT, Illumina HiSeq paired-end, 10× Genomics, and Hi-C (high-throughput chromosome conformation capture) to provide a chromosome-level genomic assembly of 'GHB' pitaya (H. undatus, 2n = 2x = 22 chromosomes). The size of the assembled pitaya genome was 1.41 Gb, with a scaffold N50 of ~127.15 Mb. In total, 27,753 protein-coding genes and 896.31 Mb of repetitive sequences in the H. undatus genome were annotated. Pitaya has undergone a WGT (whole-genome triplication), and a recent WGD (whole-genome duplication) occurred after the gamma event, which is common to the other species in Cactaceae. A total of 29,328 intact LTR-RTs (~696.45 Mb) were obtained in H. undatus, of which two significantly expanded lineages, Ty1/copia and Ty3/gypsy, were the main drivers of the expanded genome. A high-density genetic map of F1 hybrid populations of 'GHB' × 'Dahong' pitayas (H. monacanthus) and their parents were constructed, and a total of 20,872 bin markers were identified (56,380 SNPs) for 11 linkage groups. More importantly, through transcriptomic and WGCNA (weighted gene coexpression network analysis), a global view of the gene regulatory network, including structural genes and the transcription factors involved in pitaya fruit betalain biosynthesis, was presented. Our data present a valuable resource for facilitating molecular breeding programs of pitaya and shed novel light on its genomic evolution, as well as the modulation of betalain biosynthesis in edible fruits.

Betalains are water-soluble nitrogen-containing pigments with multiple bioactivities. Pitaya is the only large-scale commercially grown fruit containing abundant betalains for consumers. However, the upstream regulators in betalain biosynthesis are still not clear. In this study, HmoWRKY40, a novel WRKY transcription factor, was obtained from the transcriptome data of pitaya (Hylocereus monacanthus). HmoWRKY40 is a member of the Group IIa WRKY family, containing a conserved WRKY motif, and it is located in the nucleus. The betalain contents and expression levels of HmoWRKY40 increased rapidly during the coloration of pitaya and reached their maximums on the 23rd day after artificial pollination (DAAP). Yeast one-hybrid and transient expression assays showed that HmoWRKY40 could bind and activate the promoter of HmoCYP76AD1. Silencing the HmoWRKY40 gene resulted in a significant reduction of betacyanin contents. These results indicate that HmoWRKY40 transcriptionally activates HmoCYP76AD, which is involved in the regulation of pitaya betalain biosynthesis. The results of the present study provide new regulatory networks related to betalain biosynthesis in pitaya.

The MYB (myeloblastosis) superfamily constitutes one of the most abundant transcription factors (TFs) regulating various biological processes in plants. However, the molecular characteristics and functions of MYB TFs in pitaya remain unclear. To date, no genome-wide characterization analysis of this gene family has been conducted in the Cactaceae species. In this study, 105 R2R3-MYB members were identified from the genome data of Hylocereus undatus and their conserved motifs, physiological and biochemical characteristics, chromosome locations, synteny relationship, gene structure and phylogeny were further analyzed. Expression analyses suggested that three up-regulated HuMYBs and twenty-two down-regulated HuMYBs were probably involved in fruit ripening of pitaya. Phylogenetic analyses of R2R3-MYB repressors showed that seven HuMYBs (HuMYB1, HuMYB21, HuMYB48, HuMYB49, HuMYB72, HuMYB78 and HuMYB101) were in clades containing R2R3-MYB repressors. HuMYB1 and HuMYB21 were significantly down-regulated with the betalain accumulation during fruit ripening of ‘Guanhuahong’ pitaya (H. monacanthus). However, only HuMYB1 had R2 and R3 repeats with C1, C2, C3 and C4 motifs. HuMYB1 was localized exclusively to the nucleus and exhibited transcriptional inhibition capacities. Dual luciferase reporter assay demonstrated that HuMYB1 inhibited the expression of betalain-related genes: HuADH1, HuCYP76AD1-1 and HuDODA1. These results suggested that HuMYB1 is a potential repressor of betalain biosynthesis during pitaya fruit ripening. Our results provide the first genome-wide analyses of the R2R3-MYB subfamily involved in pitaya betalain biosynthesis and will facilitate functional analysis of this gene family in the future.

Aquaporins (AQPs) are essential membrane proteins involved in seed maturation and germination, stomata movement, photosynthesis, and regulation of plant flowering processes. Pitaya flowers are open at night and wither at daybreak, which shows an obvious circadian rhythm. In this study, a comprehensive genome-wide analysis of AQPs in Hylocereus undantus was conducted to screen key genes associated with flowering processes. A total of 33 HuAQP genes were identified from the H. undantus genome. The 33 HuAQPs were grouped into four subfamilies: 10 PIPs, 13 TIPs, 8 NIPs, and 2 SIPs, which were distributed on 9 out of 11 pitaya chromosomes (Chr) (except for Chr7 and Chr10). Results from expression profiles showed that HuNIP6;1 may be involved in pitaya's floral opening. HuNIP6;1 was localized exclusively in the cell membrane. Overexpression of HuNIP6;1 in Arabidopsis thaliana significantly promoted early flowering through regulating negative flowering regulators of MJM30, COL9, and PRR5, suggesting that HuNIP6;1 plays key roles in regulating flowering time. The present study provides the first genome-wide analysis of the AQP gene family in pitaya and valuable information for utilization of HuAQPs.