Ixora is a traditional Chinese medicinal herb, which also has ornamental values. Transcriptome sequencing was used to analyze the regulation of the pigment difference of I. coccinea A'pric Gold' and I. paruiflora. A total of 31,676 unigenes were annotated. 18,856 DEGs, 9228 up-regulated genes and 9628 down-regulated genes were obtained. EF-1 alpha gene was used as an internal reference gene. Expression patterns of 31 genes associated with the biosynthesis of chlorophyll, carotenoids and anthocyanins were significantly different. 7734 simple repeat sequences were screened out, with an occurrence frequency of 10.84 %, and 9432 eligible SSR sites were identified, with an occurrence probability of 13.22 %. Repeat types were mainly dinucleotide repeats, accounting for 49.07 % of the total. 12 primer pairs were successfully developed and used to analyze the genetic diversity of 55 Ixora genus germplasms. A total of 67 alleles were detected. The polymorphism information content (PIC) ranged from 0.0926 to 0.8376. The results of the population structure analysis were highly consistent with the phylogenetic and PCoA analysis. 55 Ixora germplasms could be classified into 4 groups. AMOVA analysis showed that the groups mainly consisted of 74.06 % of within-population variation, 25.94 % of among-population variation, and Fixation Index was 0.2594. The results provided theoretical basis for analyzing the molecular mechanism of pigment regulation, evaluating the genetic diversity of Ixora genus, and promoted the molecular breeding and development of germplasms of Ixora.

The “Guanxi” pummelo is a commercially important citrus cultivar with high fruit quality. Here, the first integrated analysis of a pummelo peel chimera, based on a naturally occurring yellow-green pericarp mutant of “Guanxi” pummelo, was reported. The molecular mechanisms underlying this chimerism were investigated through phenotypic characterization, pigment content measurement, and RNA-Seq analysis. Results revealed significant differences in chlorophyll and carotenoid contents between the green and yellow peel regions. RNA-Seq identified 1594 differentially expressed genes (DEGs), many of which are involved in chlorophyll metabolism and carotenoid biosynthesis. Key genes involved in chlorophyll degradation, such as SGR, were upregulated in the yellow peel, while carotenoid biosynthesis genes, including DXS and PSY, were also upregulated, indicating coordinated regulation of pigment metabolism. Functional enrichment analyses highlighted pathways related to chlorophyll metabolism, carotenoid biosynthesis, and photosynthesis-related processes, providing insights into the regulatory network of peel color formation. These findings provide insights into the molecular mechanisms underlying peel color variation in citrus chimeras and identify candidate genes for the genetic improvement of fruit coloration traits.

This study investigated the metabolic basis of color differentiation in Curcuma alismatifolia sterile bracts using liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based widely targeted metabolomics. We identified 1034 metabolites across different colored bract regions, with predominant classes including organic acids, amino acids and derivatives, flavonoids, lipids, terpenoids, organic heterocyclic compounds, and phenolic acids. Statistical analysis (VIP > 1, p < 0.05) revealed 118 and 104 differentially accumulated metabolites in two variety comparisons, with 61 common metabolites. Pathway analysis identified amino acid metabolism and organic acid metabolism as the most significantly altered pathways. Further analysis of the variegated regions demonstrated significant accumulation of succinic anhydride, L-tryptophan, DL-indole-3-lactic acid, uridine 5’-diphosphate galactose, and uridine 5’-diphosphate glucose, along with specific enrichment of various anthocyanin derivatives including malvidin-3-galactoside chloride, oenin chloride, and keracyanin chloride. Our results indicate that L-tryptophan, citric acid, and isocitrate are consistently associated with bract differentiation, potentially through mechanisms such as precursor supply and vacuolar pH regulation that require further validation. These findings provide insights into the metabolic framework underlying C. alismatifolia bract coloration, offering perspectives on Zingiberaceae pigmentation mechanisms and identifying potential biomarkers for ornamental plant breeding. This work provides information for the molecular characterization of this horticulturally important species and suggests candidate metabolic engineering strategies that warrant further investigation for trait improvement.

Ixora chinensis is a promising woody cut flower species. In this study, a compound vase solution was developed to effectively prolong the vase life of I. chinensis cut flowers. The physiological and molecular responses of the cut flowers to this solution were then analyzed. The single-factor test and an L9(3⁴) orthogonal test results showed that the optimal formula was 3 % glucose + 25 mg/L GA₃ + 100 mg/L 8-HQS + 80 mg/L CA. This formula extended the vase life of I. chinensis cut flowers from 9.33 days to 13.0 days, an increase of 39.3 %. It also significantly preserved the ornamental quality of the cut flowers. Physiological analyses revealed that the compound solution significantly enhanced ROS scavenging capacity. At day 7, SOD, CAT, and POD activities in the treatment group increased by 53.8 %, 72.6 %, and 182.4 %, respectively, compared with the control group. At day 10, MDA content and electrolyte leakage were reduced by 32.5 % and 33.8 %, respectively. Transcriptome sequencing and quantitative real-time polymerase chain reaction (qRT-PCR) validation demonstrated that the compound preservation solution upregulated the expression of core ROS-scavenging enzyme genes (SOD1, CAT6, APX3) at later stages. It also upregulated the ascorbic acid biosynthesis gene (GME-2). These results suggest that the compound preservation solution extends the vase life of I. chinensis cut flowers by promoting reactive oxygen species scavenging.

The complete sequence of Curcuma alismatifolia bract virus (CurABV) from the city of Zhangzhou in Fujian Province, China, was determined by high-throughput sequencing. The viral genome consists of 8273 nucleotides (nt) and encodes a large polyprotein of 2634 amino acids (aa). In silico analysis predicted that this polyprotein is cleaved by two viral proteases into nine mature proteins. Sequence comparisons showed that CurABV shares 48.60-74.40

ABSTRACT Curcumin content and expression patterns of curcumin synthase (CURS ) genes in three tissues (corms, leaves and inflorescences) of 16 Curcuma alismatifolia genotypes were analysed in this study. This study aimed to investigate the variability of curcumin content and the expression patterns of CURS genes in different tissues of various C. alismatifolia genotypes, in order to identify potential resources for curcumin extraction and genetic improvement. The curcumin synthase 2 (CURS2 ) and curcumin synthase 3 ( CURS3 ) gene sequences were successfully cloned. Significant variations in curcumin content were observed among different genotypes and tissues. In corms, Twister (0.299 mg · g −1 ) and Doitung (0.296 mg · g −1 ) had the highest curcumin levels. In inflorescences, Lanna Snow (0.375 mg · g −1 ) had the highest curcumin levels. In leaves, NewSolo (0.783 mg · g −1 ) had the highest curcumin levels. Quantitative PCR analysis revealed tissue-specific expression patterns of CURS genes: curcumin synthase 1 (CURS1 ) was highly expressed in corms, CURS2 in leaves and CURS3 in inflorescences. Additionally, CURS2 and CURS3 were successfully cloned from C. alismatifolia . Both genes have a CDS length of 1173 bp, encoding 390 amino acids, with high sequence conservation. Phylogenetic analysis indicated close evolutionary relationships between CURS genes and those from Curcuma xanthorrhiza, Curcuma longa and Zingiber officinale . This study provides a basis for curcumin extraction and genetic improvement of C. alismatifolia , and contributes to further research on curcumin biosynthesis.

Curcuma alismatifolia Gagnep. is an original ornamental flower. To induce new phenotypic variations and breed new varieties with market value, ethyl methanesulfonate (EMS) was used to treat C. alismatifolia seedlings at various concentrations (0.0%, 0.1%, 0.5%, 1.0%, 1.5% and 2.0%) and for various durations (10, 15, 30, 60, 120 and 240 min). The treatment with 0.1% concentration for 10 min resulted in the highest survival rate, while treatments with 0.6% and 0.8% concentrations for 240 min could produce more diverse phenotypes. The treatment conditions of 2.0% EMS for 10 min and 0.5% EMS for 60 min are considered the semi-lethal doses for EMS mutagenesis of C. alismatifolia. This mutagenic process effectively induced diverse phenotypic changes, such as plant dwarfism, fewer bracts, leaf adhesion, chimera formation, altered coloration of the flower petal, and leaf fusion. We used a total of 16 simple sequence repeat (SSR) markers to analyze the genetic variation of the EMS-induced C. alismatifolia seedlings. The analysis revealed the following genetic parameters: the average polymorphism information content (PIC) was 0.6044, the number of alleles (Na) ranged from 2 to 3, the number of effective alleles (Ne) varied between 1.2195 and 2.9877, and the genetic diversity index (I) was 0.7532. This study promotes the mutation breeding program of C. alismatifolia.

Curcuma alismatifolia is an attractive ornamental plant in the ginger family. Its bracts come in a variety of colors and are commonly used as cut flowers, potted plants, and landscaping. To investigate the regulation of bract pigmentation in C. alismatifolia, we examined the pigment levels of chlorophyll and carotenoids in the pure color part (PC) and variegated part (VA) of three C. alismatifolia varieties, i.e., "Siam TM Sitrone," "Chiang Mai Pink," and "Snow White." To mine the color mechanisms of the pure color and variegated parts of the bract, we conducted RNA-seq analysis on C. alismatifolia. We identified a total of 89,975 unigenes, and there were 3584 differentially expressed genes identified post-screening. Furthermore, 1858 DEGs were annotated in the GO database and 681 in the KEGG database. We pinpointed key genes responsible for the diverse bract colors in C. alismatifolia, including ZEP for carotenoid synthesis and GAGA2 in the chlorophyll synthesis pathway. This study provides valuable insights into understanding the pigmentation mechanism of bracts in C. alismatifolia and the breeding process.

Citrus fruits are widely consumed worldwide in juices or as fresh and provide a broad range of phytonutrients that are important for human health. Here, a citrus multi-omics resource is presented: comprehensive metabolic profiling of various citrus species was performed and metabolic profiles were compared among species, with a focus on the phenylpropanoid metabolic pathway. A metabolite-based genome-wide association analysis (mGWAS) of 154 pummelo accessions was performed using factored spectrally transformed linear mixed models (FaST-LMM) and efficient mixed-model association eXpedited (EMMAX), and the genetic and biochemical basis of metabolomic variation was comprehensively analysed. A metabolite-single nucleotide polymorphism-gene (metabolite-SNP-gene) interaction network was constructed for pummelo, and many candidate loci controlling the synthesis and regulation of bioactive compounds were identified; among these loci, three BAHD malonyltransferases were involved in the malonylation of flavonoid glycosides. Further investigation revealed that an R2R3-MYB transcription factor CgMYB1 positively controls the metabolism of phenylpropanoid molecules, particularly the flavonoid derivatives. This study provides valuable data resources on the metabolic regulatory networks of bioactive components in citrus, in addition to demonstrating an efficient method for metabolic pathway dissection and providing targets for future breeding work with the aim of improving nutritional value.

The orange subfamily (Aurantioideae) contains several Citrus species cultivated worldwide, such as sweet orange and lemon. The origin of Citrus species has long been debated and less is known about the Aurantioideae. Here, we compiled the genome sequences of 314 accessions, de novo assembled the genomes of 12 species and constructed a graph-based pangenome for Aurantioideae. Our analysis indicates that the ancient Indian Plate is the ancestral area for Citrus -related genera and that South Central China is the primary center of origin of the Citrus genus. We found substantial variations in the sequence and expression of the PH4 gene in Citrus relative to Citrus -related genera. Gene editing and biochemical experiments demonstrate a central role for PH4 in the accumulation of citric acid in citrus fruits. This study provides insights into the origin and evolution of the orange subfamily and a regulatory mechanism underpinning the evolution of fruit taste.

The aim of the study was to investigate the appropriate postharvest storage temperature for Pouteria caimito Radlk.,to prolong its storage life,and more broadly to expand the market for Pouteria caimito.The effects of different storage temperatures on the postharvest physiology and storage quality of P.caimito were studied by determining the main quality indices and physiological indices of fruit samples stored at 5,10,15 or 20℃after harvest.The results showed that cold storage could maintain the quality of P.caimito to a certain extent,but chilling injury(CI)symptoms,characterized by pitting and water-soaked appearance of the fruit surface and peel browning,appeared after three days of storage at 5℃.Compared with the other three storage temperatures,storage at 10℃could maintain higher levels of fruit hardness,total soluble solids(TSS),vitamin C(VC)and total sugar,and lower respiratory intensity and cell membrane permeability.Compared with 20℃,storage at 10℃could inhibit the increase of malondialdehyde(MDA)content,peroxidase(POD)and polyphenol oxidase(PPO)activity,thereby delaying the senescence and browning of P.caimito.Therefore,10℃was the appropriate storage temperature for P.caimito.The results of this study will provide a theoretical basis for postharvest quality maintenance of P.caimito.

基于 SSR分子标记技术,利用 17 对引物对 21 份多花水仙资源进行遗传多样性分析.结果表明,聚丙烯酰胺凝胶电泳共扩增出 99 条多态性条带,多态位点百分率为 93.40%.Nei's 遗传多样性指数均值为 0.266 7,Shannon信息指数均值为 0.411 7.主成分分析和 UPGMA聚类分析结果显示,供试的 21 个水仙种源分成四大类,中国水仙单复瓣种质都聚在Ⅰ类群,遗传多样性水平低,洋水仙(Grand Soleil d'Or、Ziva 和 Pearl)所在的类群(Ⅱ、Ⅲ和Ⅳ)遗传相似系数在0.4～0.8之间,类群间亲缘关系较远.本研究为今后多花水仙传统育种结合生物技术育种提供理论依据.

"貌似清荷非水生,莲荷嫁与姜科茎.问天剑叶花娇容,待开酷暑溢香庭."近几年,小众植物姜荷花火了,它凭借温婉如莲的花姿、高洁清雅的特性、观赏期长等优点,受到了很多人的喜爱. 姜荷花(Curcuma alismatifolia Gagnep.)为姜科姜黄属多年生草本热带球根植物,原产泰国北部及柬埔寨的热带和亚热带地区.因其花形似荷花而得名,享有"热带郁金香"之美誉.株高35～120厘米,根茎纺锤形至圆球形,块根近球形.

Curcuma alismatifolia is a showy ornamental of the genus Curcuma. Thirty-two C. alismatifolia accessions with high morphologic diversity were collected in this study. A total of 139 alleles were detected by 27 SSR markers. The average values of Shannon's Information index (I) and polymorphism information content were 1.267 and 0.667, respectively. Population structure about the C. alismatifolia accessions was first reported, and the 32 C. alismatifolia accessions were divided into two groups. The genetic differentiation (Fst) between these two groups was 0.127. Phylogenetic analysis showed that two clusters of the whole accessions in the study were related to pedicel length, inflorescence length and yield. The results suggested a high level of genetic diversity among these accessions. Taken together, this study provides a reference for C. alismatifolia industry and a new insight into the genetic diversity and population structure, as well as promotes the breeding program of C. alismatifolia.

Anthocyanins play a critical role in flower colour pattern formation, and their biosynthesis is typically regulated by transcription factors (TFs). Curcuma alismatifolia is a well-known ornamental plant with colourful flowers. However, little is known about the genes that regulate anthocyanin accumulation in C. alismatifolia. In the present study, high-quality RNA was extracted from three flowering stages of ‘Dutch Red’ and the blossoming stage of ‘Chocolate’. In all, 576.45 Mb clean data and 159,687 de-redundant sequences were captured. The Kyoto Encyclopedia of Genes and Genomes analysis showed that the pathways of phenylpropanoid biosynthesis, flavonoid biosynthesis, flavone and flavonol biosynthesis, and terpenoid backbone biosynthesis were the most enriched. Thirty unique isoforms were annotated as encoding enzymes or TFs involved in anthocyanin biosynthesis. Further analysis showed that the up-regulation of anthocyanin biosynthesis genes was associated with the red colour formation of ‘Dutch Red’, and their expression was induced at the initial flowering stage. The gene flavonoid 3′, 5′-hydroxylase, a key enzyme in the formation of delphinidin-based anthocyanins, reduced expression in ‘Chocolate’. In addition, we identified totally 14 TFs including 11 MYB proteins and 3 WD proteins, which might play important roles in the regulation of anthocyanin biosynthesis. The quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) results were generally consistent with the high-throughput sequencing results. Together, the results of our study provide a valuable resource for the regulatory mechanism of anthocyanin biosynthesis in C. alismatifolia and for the breeding of Curcuma cultivars with novel and charming flower colours.

研究龙船花(Ixora chinensis Lam)花药诱导愈伤组织的培养条件,探索不同浓度植物生长调节剂以及低温预处理对诱导龙船花花药愈伤组织的影响.以"杏黄色龙船花"(I.coccinea cv"Apricot Gold")和"宫粉龙船花"("Ixora×westii")品种为材料,分别将其单核期花药在含有不同植物生长调节剂2,4-二氯苯氧乙酸(2,4-D)和6-糖基氨基嘌呤(KT)浓度组合的培养基中诱导愈伤,并统计诱导率;将花药在4℃低温分别预处理0、24、48、72 h,分别进行培养后统计龙船花花药愈伤诱导率.结果表明:仅"杏黄龙船花"花药在含有不同浓度2,4-D和KT的培养基中均能诱导出愈伤,其中含4 mgL-12,4-D和2 mgL-1 KT组合在花药培养40 d时诱导率最高,为73.06％;在诱导前将龙船花花药进行4℃低温预处理有利于愈伤组织的诱导形成,并且低温预处理24 h后诱导愈伤效果最好,诱导率最高为75％.

Fruit shape is an important trait for fruit appearance and commercial value. Diversity of fruit-shape has been utilized in the breeding of pummelo (Citrus maxima), a basic species in Citrus. However, little is known about genetic basis of fruit shape in citrus. In this study, we identified 16 OVATE family protein (OFP) genes in the pummelo genome. Phylogenetically, they were classified into three subfamilies, which was consistent with the classification of their Arabidopsis orthologs. Synteny analysis suggested that segment and tandem duplications were responsible for their expansion in pummelo. Expression pattern analysis of Citrus OFPs (CitOFPs) showed that CitOFP19 had significantly higher expression level in the ovaries of round pummelo than in those of pear-shaped pummelo. Heterologous overexpression of CitOFP19 in tomato resulted in pear-shaped ovary and fruit shape. Taken together, this study characterized OVATE gene family in Citrus genome and assessed the function of CitOFP19.

KEY MESSAGE:Here, we developed a reliable protocol for the fast and efficient gene-edited Anliu sweet orange plants production. The application of in vitro shoot grafting technology significantly reduced the growth cycle of transgenic seedlings, and the survival rate of cleft grafting was more than 90%. In addition, the mutation efficiency of the grafted geneedited sweet orange was significantly improved by short-term heat stress treatments. Thus, the combination strategy of grafting and heat stress treatments provided a reference for the fast and efficient multiplex gene editing of sweet orange.

Somatic variations are a major source of genetic diversification in asexual plants, and underpin clonal evolution and the breeding of asexual crops. Sweet orange is a model species for studying somatic variation because it reproduces asexually through apomixis and is propagated asexually through grafting. To dissect the genomic basis of somatic variation, we de novo assembled a reference genome of sweet orange with an average of three gaps per chromosome and a N50 contig of 24.2 Mb, as well as six diploid genomes of somatic mutants of sweet oranges. We then sequenced 114 somatic mutants with an average genome coverage of 41×. Categorization of the somatic variations yielded insights into the single-nucleotide somatic mutations, structural variations and transposable element (TE) transpositions. We detected 877 TE insertions, and found TE insertions in the transporter or its regulatory genes associated with variation in fruit acidity. Comparative genomic analysis of sweet oranges from three diversity centres supported a dispersal from South China to the Mediterranean region and to the Americas. This study provides a global view on the somatic variations, the diversification and dispersal history of sweet orange and a set of candidate genes that will be useful for improving fruit taste and flavour.

Curcuma alismatifolia are widely used as an ornamental plant in Thailand, Cambodia and China, which have become increasingly popular as cut flowers, garden plants and urban landscaping flowers. Thus it is of great interest to understand the physiologic and molecular characteristics in the C. alismatifolia cultivars. Although only a very limited number of molecular biology experiments were conducted in C. alismatifolia, the obtained data currently have led to a better understanding of their genetic variation and the responses to environmental stimuli. This review presents the current available genetic markers, new breeding varieties, bioactive compounds (in different parts of the plant) and the stress physiology in C. alismatifolia cultivars, which may be beneficial for the future marker-assisted selective breeding and for the studies on the molecular mechanisms. Future challenges and research opportunities in the physiology and molecular biology are also discussed.