Aroma is a crucial factor influencing the flavor quality and economic value of longan fruits. This study employed a mapping population consisting of 98 F1 progeny of ‘Shixia × Xiangcui’ (exhibiting broad segregation in fruit aroma trait) and their parents. We performed the SNP genotyping through whole-genome resequencing to construct a high-density linkage map, followed by QTL mapping and candidate gene screening for aroma trait. We obtained a total of 554.9 Gbp of sequencing data, with an average depth of approximately 15× for the parents and 12× for the progeny. Three types of SNP markers (lm×ll, nn×np, and hk×hk) were developed, totaling 317 877. After merging with a 100 kb sliding window, 6 134 Bin markers were generated. A first high-density Bin map was constructed, comprising 15 linkage groups with 3 517 Bin markers (containing 264 385 SNPs), covering a total map length of 1 666.79 cM. The average marker interval was 0.48 cM, with 99.18% of gaps being less than 5 cM. Collinearity analysis confirmed the high quality of the map. Fifty-six QTLs were mapped for 9 aroma-related traits, including (E)-2-hexenal, ethyl acetate, ethyl butyrate, ethyl crotonate, (E)-2-hexenoate, ethanol, linalool, ocimene, and total ester content. These QTLs explained 19.8%–51.0% of the phenotypic variation rates and were distributed across 11 linkage groups, with two QTL-rich regions on LG7 and LG8. Seven pleiotropic QTLs were detected. By analyzing the expression patterns of 1 535 annotated genes within the mapped intervals, six candidate genes potentially regulating the synthesis of ester characteristic aroma compounds were identified: aldo-keto reductase AKRs, acetolactate synthase small subunit ALS2, ACC oxidase ACO1-1, and transcription factors bHLH122, AGL103, and bZip1. This work provides novel insights into the fruit aroma formation, and facilitates breeding efforts to improve quality in longan and potentially other fruit crops.

Longan (Dimocarpus longan Lour.) is a commercially valuable tropical fruit crop that contains two antagonistic FLOWERING LOCUS T (FT) homologs involved in regulating flowering time. However, how these FT genes interact with flowering regulators FLOWERING LOCUS D (FD) and APETALA1 (AP1) remains unknown. Four flowering-related genes in longan, DlFT1, DlFT2, DlAP1 and DlFD, were successfully isolated. Expression profiling revealed that all four genes were expressed in leaves and buds across different stages of natural and KClO3-induced floral bud differentiation. Functional characterization through heterologous overexpression in Arabidopsis thaliana showed that DlAP1 significantly promotes early flowering under long-day conditions and induced morphological changes in floral organs and leaves. In contrast, DlFD overexpression had no effect on flowering time. Subcellular localization assays revealed that DlFT1 and DlFT2 localized to both the nucleus and the plasma membrane, while DlAP1 and DlFD localized exclusively to the nucleus. Yeast two-hybrid and bimolecular fluorescence complementation (BiFC) analyses revealed a novel regulatory node: DlFT1 directly interacts with DlAP1, a finding that expands the classical FT-FD-AP1 flowering model. Additionally, DlFD interacts more strongly with DlFT1 than with DlFT2, whereas DlFT1 only interacts with DlAP1, but not DlFT2. These results demonstrate that DlFT1 promotes flowering not only via the conserved FD-dependent pathway but also through direct association with AP1. These findings advance our understanding of the regulatory mechanisms of flowering in longan and provide valuable insights into flowering pathways of perennial woody species.

Longan is an exotic tropical fruit crop and exhibits off-season flowering induced by potassium chlorate (KClO3), though the molecular mechanisms remain unclear. We assembled a high-quality, 441.5 Mb genome of variety 'Shixia', with a contig N50 at 28.1 Mb, 29, 325 protein-coding genes, 26 telomeres and 15 centromeres. Comparative genomic analysis with lychee revealed structural variations potentially driving gene family expansions related to flavone biosynthesis and disease resistance. Transcriptomic profiling showed that natural flowering appears to be primarily regulated by photoperiod, vernalisation and autonomous pathways, while KClO3-induced flowering may preferentially activate the gibberellin pathway at 5 days after treatment (DAT) and autonomous pathways at 10 DAT, involving putative repression of DlDDF1, DlFLCs and DlSVPs, and up-regulation of DlWRKY75_2. In the perpetual-flowering variety 'Sijimi', elevated expression of photoperiod genes, such as DlCOR28, DlCOR27, DlADO3, DlPRR5, DlGI and DlJMJ30, may explain its perpetual blooming. Overexpression of DlDDF1 in Arabidopsis delayed flowering, partially reversed by KClO3 through an increase in bioactive GA4. Together, KClO3-induced flowering likely involves oxidative stress response and gibberellin signalling via DlDDF1 repression, while natural flowering relies on seasonal cues. These results lay the foundation for longan genetic improvement.

"宝石1号"龙眼是福建省农业科学院果树研究所杂交选育的龙眼新品种,具有丰产稳产、可食率高、果肉爽脆、化渣、风味甜、含糖量高等优点,2017年引种到海南省儋州市.在海南省儋州市,"宝石1号"龙眼生长旺盛,能够快速形成丰产树冠,盛花期在3月下旬,果实成熟期7月中旬,平均单果质量13.8～14.2 g,可溶性固形物含量为17.9％～19.6％,可食率72.9％～75.7％,优于目前儋州主栽品种"石硖".采用反季节催花栽培,"宝石1号"龙眼的现花期比"石硖"早,成花率比"石硖"高.

福圆是立冬本×青壳宝圆的杂交子代,通过选择优良单株,定向培育而成的晚熟优质大果型龙眼新品种.树势中庸,成花易、高坐果率、早丰产;果皮青褐色,果实侧偏圆形,大小均匀,平均单果质量14.6 g;果肉乳白色、半透明,肉质细嫩、较易离核,可溶性固形物含量(w,后同)21.9％,还原糖含量6.5 g·100 g-1,总糖含量17.9 g·100 g-1,维生素C含量90.7 mg·100 g-1,可食率69.4％,味浓甜,品质佳.在福州地区,果实9月中下旬成熟;高接后3年生树平均果穗质量1190.5 g,平均株产7.2 kg;4年生树平均果穗质量1212.6 g,平均株产18.1 kg;丰产、稳产性好,连年结果能力强.适宜在福建福州、四川泸州、重庆万州及相似生态区栽培.

Longan (Dimocarpus longan Lour.) is an important economic crop widely planted in tropical and subtropical regions, and flower and fruit development play decisive effects on the longan yield and fruit quality formation. MCM1, AGAMOUS, DEFICIENS, Serum Response Factor (MADS)-box transcription factor family plays important roles for the flowering time, floral organ identity, and fruit development in plants. However, there is no systematic information of MADS-box family in longan. In this study, 114 MADS-box genes were identified from the longan genome, phylogenetic analysis divided them into type I (Mα, Mβ, Mγ) and type II (MIKC*, MIKCC) groups, and MIKCC genes were further clustered into 12 subfamilies. Comparative genomic analysis of 12 representative plant species revealed the conservation of type II in Sapindaceae and analysis of cis-elements revealed that Dof transcription factors might directly regulate the MIKCC genes. An ABCDE model was proposed for longan based on the phylogenetic analysis and expression patterns of MADS-box genes. Transcriptome analysis revealed that MIKCC genes showed wide expression spectrums, particularly in reproductive organs. From 35 days after KClO3 treatment, 11 MIKC genes were up-regulated, suggesting a crucial role in off-season flower induction, while DlFLC, DlSOC1, DlSVP, and DlSVP-LIKE may act as the inhibitors. The gene expression patterns of longan fruit development indicated that DlSTK, DlSEP1/2, and DlMADS53 could be involved in fruit growth and ripening. This paper carried out the whole genome identification and analysis of the longan MADS-box family for the first time, which provides new insights for further understanding its function in flowers and fruit.

Huataifeng (HTF) is an eminent cultivar selected from the crossing of Shixia and Xiangcui created and evaluated at National Longan Germplasm Nursery in Fuzhou, Fujian, China. Shixia is a prominent cultivar with high quality and fertility native to Guangdong, populous among Chinese cus-tomers. Xiangcui is a bud-mutation from Biew Khiew (a Thailand cultivar) with large fruit size and abundant fragrance. The hybrid was created in 2009 via artificial pollination, 148 seeds were gathered and consequently 112 seedlings were obtained. Line 09-1-70 (ultimately named HTF) was selected from the cross population for its early bearing capacity (fruiting initiated in 2012). Longan production suffered severe yield lose in Fujian province in 2013 due to off-year bearing, while HTF had a high flowering rate and yield as usual. The stable flower formation of this line might give rise to stable fruit production. It was then to top-grafted onto a mature longan tree in 2013. The grafted trees started to bear fruit in 2014, and from 2014 to 2017 all the grafted trees showed stable and consistent characteris-tic including high flesh recovery, high total soluble sugar content and abundant fragrance. Its fruit weight is 27.8%-48.2% higher than that of Shixia. From 2018 to 2021, HTF was the most consistent bearing line and showed no alternative bearing problem. Consequently, in 2021, HTF was certified in Fujian Province (no. 9352021Y0075). This cultivar has a strong growth vigor and a semi-open tree ar-chitecture. The bark is gray-brown and split into narrow rough ridges. Twigs are red-brown and smooth.The mature compound leaves are in size of (14.1-26.0) cm × (12.2-25.1) cm, and their 4-5 pairs of leaf-lets are green, lanceolate, and (12.8-18.7) cm × (3.9-4.7) cm in size. The leaf margins are wavy, and apex narrowly acuminate. The juvenile phase of 3 years of this cultivar is rather short. And it forms in-florescence every year. Its flower cluster is large and scattered. The oblate fruit are uniform in size with a blue-brown pericarp. The fruit base is flat, sometimes with one risen shoulder and the fruit tip is round. The skin segments are obvious. The fruit has an average longitudinal diameter of 2.73-2.81 cm, average transverse diameter of 2.89-2.93 cm, and average lateral diameter of 2.67-2.70 cm. The aril is milky, translucent, fragrant, tender and crisp, and can be easily separated from the seed. Average fruit weight is (12.7±1.0) g. The flesh recovery is (70.8±1.6)%, and TSS (22.7±2.8)%. HTF has an excellent grafting affinity to many main cultivars, such as Shixia and Chuliang (mainly cultivated in Guangdong province, Hainan province and Guangxi Autonomous Region), Fuyan, Songfengben, Lidongben (main-ly cultivated in Fujian province), and Shuguan, Lufeng (mainly cultivated in Sichuan province). The productivity of 7-year-old grafted trees can be up to 26.3 tons per ha (density 600). Bud breaking of HTF begins in late February, similar to that of Shixia, and the first leaf matured in late May. Inflores-cence morphological differentiation initiates in late February; flowers bloom from late April to early May, and ends in late May. The fruit matures during early September to early October in Fuzhou.

Abstract Longan was a characteristic fruit for both medicine and food in China, which was rich in primary and secondary metabolites. Comprehensive high‐throughput identification and comparison of metabolites in longan pulp among different varieties were still lacked. “Shixia” (SX) and “Chuliang” (CL) were the biggest major cultivars of longan in China. In this study, the content of total soluble solid, total flavonoid, and total phenolics indicated the difference of sweetness and bioactive compound content between the SX and CL pulp. Through a widely targeted metabolome, a total of 514 metabolites were identified and categorized into 23 groups mainly including flavonoids, amino acids & derivatives, lipids, phenolic acids, nucleotides & derivatives, alkaloids, organic acids and sugars & derivatives. A total of 89 metabolites with significantly differential accumulation (variable importance in projection (VIP) value ≧1, p‐value <.05) over 1.2 fold were found between SX and CL, which were mainly enriched into pathways including flavone and flavonol biosynthesis, glycolysis/gluconeogenesis, and arginine and proline metabolism. Higher leveled hexose and hexose‐phosphate (i.e., β‐D‐glucose, D(+)‐glucose, glucose‐1‐phosphate and glucose‐6‐phosphate), dominant organic acids (i.e., citric acid, succinic acid, D‐malic acid, and citramalate), and essential amino acids (L‐threonine, L‐valine, L‐isoleucine, L‐leucine, L‐phenylalanine and L‐lysine) in SX pulp might be contributed to the taste and flavor difference between SX and CL. Moreover, the greatly differential accumulated secondary metabolites especially flavonoids and phenolic acids might result in different medicinal and nutritional characteristic between SX and CL. In conclusion, this study provided a systemic metabolic basis for understanding the nutritional differences between SX and CL and would help deepen the molecular biology and pharmacology research on characteristic metabolites in longan pulp.

利用SLAF-seq测序技术,开发一批特异性强、稳定性高的单核苷酸多态性(SNP)位点,为枇杷遗传图谱构建、分子辅助育种和物种进化等研究提供理论依据.本研究共收集294份枇杷属资源,利用SLAF-seq测序技术进行测序.以梨基因组为参考基因组进行电子酶切预测,确定使用HaeⅢ+Hpy166Ⅱ进行酶切,构建SLAF-seq文库,而后筛选314～364 bp长度的DNA片段定义为SLAF标签,预测可得到116 171个SLAF标签.共获得526.63 Mreads数据,各样品所获得的读长数目在119893～9305 152范围内,平均读长为1 787581;测序质量值Q30的范围在88.26％～95.67％,平均为93.61％;GC含量分布在38.79％～42.92％范围内,平均值为40.35％.本实验以水稻测序获得0.16 M reads的数据量为Control,双端比对效率在91.28％,说明SLAF建库基本正常.生物信息学分析结果显示本研究共获得623 356个SLAF标签,且有123 498个多态性的标签,多态性为19.81％.在多态性SLAF标签上开发得到1 604 434个群体SNP标记.根据完整度＞0.8,MAF＞0.05过滤,共得到95 960个高一致性的群体SNP.

本研究以龙眼早熟品种'石硖'、晚熟品种'香脆'与'立冬本'的4个不同发育阶段的果肉为试材,利用q-PCR技术对EF-1α-1、EF-1α-2、Actin1、Actin2及GAPDH2等5个候选内参基因的表达水平进行检测,并采用geNorm、NormFinder、BestKeeper和ReFinder软件综合分析评价其稳定性.结合应用验证,最终得出EF-1α-1、EF-1α-2和Actin2是龙眼果实发育q-PCR的适宜内参基因.

引进9个龙眼品种进行区试试验,观察各品种嫁接亲和性和接穗生长情况.开展不同砧木接口直径嫁接试验,比较不同砧木接口直径对嫁接亲和性和接穗生长的影响.试验结果表明,龙眼优新品种(系)'福晚1号''福晚8号''高宝''福晚9号''96-68'和'立冬本'在泸州嫁接成活率较高,'福晚8号''宝石1号''高宝''榕育8号'和'松风本'嫁接后枝梢生长较快,'福晚1号'和'福晚9号'嫁接后枝梢生长相对较弱.大枝嫁接(嫁接口直径在3～6cm)在成活率、侧枝数量、枝梢长度和粗度上均优于小枝嫁接(嫁接口直径在0.5?1.5cm).

Amino acids are important component of fruit nutrition and quality. In this study, three longan cultivars, including non-aroma types ‘Shixia’ (SX), ‘Lidongben’ (LDB), and strong aroma type ‘Xiangcui’ (XC), were selected to analyze free amino acids (FAAs) variations at six distinct growth stages (S1–S6). The genome-wide identification and expression analysis of genes related to the branched-chain amino acids (BCAA) synthesis pathway were carried out. Results showed that 36 FAAs were identified, and the total FAAs content ranged from 2601.0 to 9073.5 mg/kg, which increased drastically with fruit development until ripening. L-glutamic acid (Glu), L-alanine (Ala), L-arginine (Arg), γ-Aminobutyric acid (GABA), L-aspartic acid (Asp), L-leucine (Leu), hydroxyl-proline (Hypro), and L-serine (Ser) were the predominant FAAs (1619.9–7213.9 mg/kg) in pulp, accounting for 62.28–92.05% of the total amino acids. During the period of rapid fruit expansion (S2–S4), the aroma of XC changed from light to strong, and the contents of L-alanine (Ala) and L-leucine (Leu) were significantly higher than those of SX and LDB. Furthermore, a total of two 2-isopropyl malate synthase (IPMS), two 3-isopropyl malate dehydrogenase (IPMD), and 16 BCAA transferase (BCAT) genes were identified. The expression levels of DilBCAT1, -6, and -9 genes in XC were significantly higher than those in SX and LDB, while DilBCAT16 in XC was lower. The content of Leu was negatively correlated with the expression of DilBCAT1, -6, and -9 in three varieties, but positively correlated with DilBCAT16, indicating that these four genes may be responsible for the different synthesis and degradation of Leu among cultivars.

Loquat (Eriobotrya japonica) is a subtropical tree that blooms in autumn, and its fruits ripen during late spring. Sunburn caused by high temperature and high light intensity is one of the most severe abiotic stress factors that decreases loquat productivity and fruit quality and shelf life, greatly inhibiting sustainable development of this fruit crop industry. To date, little is known about fruit heat tolerance regulation, and investigation of heat stress responses and thermotolerant improvement is important for fruit crops. 'Wuduiyadanben' loquat fruits under 40 degrees C stress were collected for physiological and comparative sequencing analyses; hormone changes in loquat fruit in response to heat stress were investigated using liquid chromatography-mass spectrometry (LC-MS) analysis. Several discriminatory hormone metabolites were identified, including fourteen cytokinins (CK), eight auxins, five jasmonic acids (JA), three gibberellin acids (GA), two abscisic acids (ABA), two salicylic acids (SA), one ethylene (ETH) and one strigolactone (SL). Transcriptomics analysis suggested that genes enriched in 'Plant hormone signal transduction', 'Protein processing in endoplasmic reticulum', 'Photosynthesis', 'Plant-pathogen interaction' and 'Oxidative phosphorylation' pathways are involved in the heat stress response. Additionally, small RNA analysis further revealed that miRNAs, including miRNA160-x, miRNA393-x, miR6187-x, miR8726-y and novel-m0057-5p, might act together with auxin signaling and heat shock proteins to regulate genes in the heat stress response process. In summary, this study provides a comprehensive understanding of the complex molecular mechanisms underlying the thermal stress responses of loquat fruit.

本试验利用氨基酸自动分析仪,建立龙眼果实游离氨基酸组分的准确测定方法,并对晚熟品种'立冬本'氨基酸组成及含量进行分析.结果表明,氨基酸混合标准溶液中38种组分在色谱图中得到了较好分离.'立冬本'龙眼果实上共检测到30种游离氨基酸,总含量达5 942.7 mg kg-1,蛋白和非蛋白游离氨基酸占比分别为83.00％和17.00％;必需氨基酸(6种)总含量为245.1 mg kg-1,占比4.12％;鲜味氨基酸和甜味氨基酸含量丰富,占比分别为52.83％和25.08％,苦味氨基酸含量相对较少;与香气物质合成相关的氨基酸(6种)含量占比为21.85％.

为探究枇杷(Eriobotrya japonica)杂交品种真实性和DNA指纹图谱,对新育成的19个枇杷杂交品种(系)进行SSR标记鉴定分析.结果 表明,从已发表的89对SSR引物中筛选出扩增条带清晰稳定的多态性引物19对,在24份枇杷材料中共扩增到83条带,每对引物平均扩增4.37条,PIC值为0.234～0.983,平均为0.764.经12对具有父本特征带多态性引物鉴定,19个杂交新品种(系)全部为真杂种,真杂种率为100％.UPGMA聚类分析表明,19个杂交新品种(系)的遗传相似系数为0.728～0.969,与杂交亲本‘新白2号’和‘贵妃’聚为同一个大类,并可细分为4个亚类,红肉与白肉的枇杷品种(系)间无明显划分.同时利用8对多态性SSR引物组合,构建了19个枇杷杂交新品种(系)的分子指纹图谱.这为枇杷品种鉴定、新品种权保护和杂交育种提供重要参考依据.

[目的]研究福建地区龙眼花精油的主要化学成分.[方法]通过水蒸气蒸馏法对龙眼花精油成分进行提取,利用固相微萃取技术对样品进行采集,气相色谱-质谱(GC-MS)法和计算机谱库对样品成分进行分离分析,结合人工谱图解析对龙眼花精油成分进行鉴定.[结果]共检测出95种化学成分,通过面积归一化法确定了各化学成分的百分比含量,进一步归类得出:烷烃、烯烃类相对含量为42.35％,芳香烃40.30％,醇类13.05％,酯类0.61％,醛类0.36％,酮类0.25％.[结论]该研究结果为合理应用福建产龙眼花药材提供一定的科学依据.

‘早钟6号’枇杷特早熟且品质好,现已成为我国的主栽枇杷品种.近年来由于劳动力价格上涨,管理成本逐年提高,生产效益降低.笔者着手对该品种的控冠矮化、修剪、疏花疏果、施肥等关键栽培技术进行集成创新,总结出一套‘早钟6号’枇杷省力化高效栽培技术.该技术的推广应用能显著降低管理成本,同时还能提高果实品质及提早成熟期.

以96-1、 反季节龙眼、 立冬本、 松风本、 晚香、 翠玉、 施冲蒲等7份龙眼种质果实为试材,利用高效液相色谱法(HPLC)对成熟期和挂树保鲜后的果实糖组分含量进行测定分析.结果表明:7个龙眼种质挂树保鲜7～26 d后,果糖和葡萄糖含量提高,蔗糖含量降低,果糖/葡萄糖的值不变;果糖和葡萄糖含量增幅最大的是翠玉(比增62.2％、64.9％),其次是晚香(比增44.3％、45.5％),最小的是反季节龙眼(比增7.8％、5.3％),蔗糖含量降幅最大的是立冬本(下降21.7％),其次是翠玉(下降21.4％),最小的是晚香(下降1.2％),'晚香'、'翠玉'的总糖、 甜度值升高,其他5个品种的总糖、 甜度值降低;糖组分含量和比例的变化导致了不同种质挂树前后风味品质的差异.