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This report presents the development of a highly effective method employing high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS) to investigate chlorantraniliprole's dissipation, risk assessment, and residue distribution in whole lychee fruit and its pulp. Mean recoveries of the samples ranged from 80 to 105%, exhibiting a relative standard deviation (RSD) of below 8%. The limits of quantification (LOQ) for lychee and pulp were determined as 0.001 mg/kg, and half-lives (t1/2) ranged from 8.0 to 12.2 days. Terminal residue concentrations in whole litchi and pulp were determined as 0.008–0.45 mg/kg and ≤0.001 mg/kg. These residues were treated twice and thrice at two different dosage levels with pre-harvest intervals (PHIs) of 7, 14, and 21 days. The potential chronic risk posed by chlorantraniliprole to humans was non-negligible, as indicated by the risk quotient (RQ) value not exceeding 1. Therefore, this study provides significant fresh data about the safe application of chlorantraniliprole in the production of lychee, which will help China develop maximum residual limits (MRLs). [ABSTRACT FROM AUTHOR]

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Selenium cathodes are expected to become next‐generation energy storage materials due to their high electronic conductivity and volumetric capacity. However, their commercial applications are hindered by polyselenides dissolution and low Se utilization. Herein, a biomass compound, namely lychee seed, is used as a sustainable precursor to design hierarchically porous carbon by a single‐step carbonization activation method. With a unique hierarchical porous structure, the lychee seed–derived activated carbon (LSDAC) used to encapsulate selenium delivers a reversible capacity of 446 mA h g−1 at 2 C and 291 mA h g−1 at 5 C after 1000 cycles. The Se/LSDAC electrodes show the most favorable fast‐charging and good cycling behavior compared to the previously reported biomass‐based carbon materials. By increasing the Se area loading to 9.5 mg cm−2, the Se/LSDAC cathode maintains an areal capacity of 3.7 mA h cm−2 (3.2 mA cm−2 areal current density) after 80 cycles. High Se loading and economical and fast‐charging cathode designs in Li–Se batteries are inspired. [ABSTRACT FROM AUTHOR]

Bimetallic (Ag-Au/Au-Ag) nanoparticles have been synthesized using Litchi chinesis leaf extract and characterised using UV-visible spectroscopy, dynamic light scattering (DLS), zeta potential and transmission electron microscopy (TEM). The hydrodynamic size of Ag-Au/Au-Ag NPs are found to be 83 nm/90 nm, respectively, by DLS techinque. The catalytic capability of green synthesised silver, gold and bimetallic(Ag-Au) nanoparticles is described in this study by choosing the degradation of methylene blue, as a model dye. [ABSTRACT FROM AUTHOR]

Main conclusion: Sunlight boosts anthocyanin synthesis/accumulation in sunny pericarp of litchi fruit, directly leading to uneven pigmentation. Distribution discrepancy of mineral element aggravates uneven coloration by modulating synthesis/accumulation of anthocyanin and sugar. Uneven coloration, characterized by red pericarp on sunny side and green pericarp on shady side, impacts fruit quality of ‘Feizixiao’ (cv.) litchi. The mechanisms of this phenomenon were explored by investigating the distribution of chlorophyll, flavonoids, sugars, and mineral elements in both types of pericarp. Transcriptome analysis in pericarp was conducted as well. Sunny pericarp contained higher anthocyanins in an order of magnitude and higher fructose, glucose, co-pigments (flavanols, flavonols, ferulic acid), and mineral elements like Ca, Mg and Mn, along with lower N, P, K, S, Cu, Zn and B (P < 0.01), compared to shady pericarp. Sunlight regulated the expression of genes involved in synthesis/accumulation of flavonoids and sugars and genes functioning in nutrient uptake and transport, leading to asymmetric distribution of these substances. Anthocyanins conferred red color on sunny pericarp, sugars, Ca and Mg promoted synthesis/accumulation of anthocyanins, and co-pigments enhanced color display of anthocyanins. The insufficiencies of anthocyanins, sugars and co-pigments, and inhibition effect of excess K, S, N and P on synthesis/accumulation of anthocyanins and sugars, jointly contributed to green color of shady pericarp. These findings highlight the role of asymmetric distribution of substances, mineral elements in particular, on uneven pigmentation in litchi, and provide insights into coloration improvement via precise fertilization. [ABSTRACT FROM AUTHOR]

Theoretically, lactic acid bacteria (LABs) could degrade polyphenols into small molecular compounds. In this study, the biotransformation of lotus seedpod and litchi pericarp procyanidins by Lactobacillus plantarum 90 (Lp90), Streptococcus thermophilus 81 (ST81), Lactobacillus rhamnosus HN001 (HN001), and Pediococcus pentosus 06 (PP06) were analysed. The growth curve results indicated that procyanidins did not significantly inhibit the proliferation of LABs. Ultra-high-performance liquid chromatography high-resolution mass spectrometry (UPLC–HRMS) revealed that procyanidin B2 and procyanidin B3 in lotus seedpod decreased by 62.85% and 25.45%, respectively, with ST81 metabolised, while kaempferol and syringetin 3-O-glucoside content increased. Although bioconversion did not increase the inhibitory function of procyanidins against glycosylation end-products in vitro, the 2,2′-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) free radical scavenging capacity and ferric reducing antioxidant power of litchi pericarp procyanidins increased by 157.34% and 6.8%, respectively, after ST81 biotransformation. These findings may inspire further studies of biological metabolism of other polyphenols and their effects on biological activity. [ABSTRACT FROM AUTHOR]

Litchi (Litchi chinensis Sonn.) is a type of commercially prevalent subtropical and tropical fruit. Since litchi has a highly heterozygous genetic background and a long reproductive cycle, conventional breeding methods (such as hybridization) have limited ability to nurture new litchi cultivars. Here, an efficient and stable Agrobacterium tumefaciens-mediated genetic transformation of embryogenic callus was established in ‘Feizixiao’ litchi. Transgenic materials were verified using polymerase chain reaction (PCR) analysis, β-glucuronidase (GUS) assay, and green fluorescent protein (GFP) assay. To implement the technology of the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/associated protein 9 (CRISPR/Cas9) technology in ‘Feizixiao’ litchi and verify the validity of these transformation systems, the litchi polyphenol oxidase gene (LcPPO, JF926153) was knocked out. Various categories of mutations, covering base insertions, deletions, and substitutions, were found in transgenic materials via sequence analysis. The transformation system achieved high feasibility and efficiency, and the system of CRISPR/Cas9 was successfully employed to edit genes in ‘Feizixiao’ litchi. This work provides an essential foundation for investigating the functions of genes and accelerating litchi genetic improvement.

【Objective】This study aims to discover members of the Al-activated malate transporter ALMT gene family that may be involved in the growth and development of litchi and to investigate their biological functions.【Method】The physicochemical properties of proteins, subcellular localisation predictions, phylogeny, gene structure, conservative motifs, chromosomal positioning, promoter cis-acting elements, protein structure and expression patterns of litchi ALMT gene family members were systematically analysed using bioinformatics methods, expression of the litchi LcALMTs was analysed by qPCR.【Result】The results showed that the litchi LcALMT gene family has 16 members with CDS lengths ranging from 118 to 803 bp and isoelectric points between 5.16 and 9.07. Subcellular localisation predictions showed that the LcALMTs were all localised to the plasma membrane, and the family was divided into five subclades based on a phylogenetic tree. The number of exons of the LcALMTs ranged from 3 to 10, and four LcALMT genes did not contain any non-coding regions. Chromosomal localisation analysis revealed that LcALMTs was localised on only six of the 15 chromosomes of litchi, and mainly on chromosome 13. Conservative motif analysis revealed that litchi ALMT family members contain both ALMT and ALMT superfamily structural domains. Among the cis-acting elements, light-responsive elements accounted for the largest proportion, followed by hormone-responsive elements. Expression pattern analysis revealed that the expression of Litchi LcALMTs was highly variable in different tissues, with LcALMT5 and LcALMT15 being expressed at high levels in all tissues, the qPCR results showed that the expression level of LcALMT5 was more consistent with the results of the transcriptome.【Conclusion】There are 16 members of the litchi ALMT Gene family, which has a conservative gene structure and protein domain, and there are differences in tissue expression.

In the post-harvest phase, fruit is inexorably subjected to extrinsic stressors that expedite energy expenditure and truncate the storage lifespan. The present study endeavors to elucidate the response strategies of litchi to the alterations of energy state caused by 2,4-Dinitrophenol (DNP) treatment through energy metabolism and sugar metabolism. It was observed that the DNP treatment reduced the energy state of the fruit, exacerbated membrane damage and triggered rapid browning in the pericarp after 24 h of storage. Furthermore, the expression of genes germane to energy metabolism (LcAtpB, LcAOX1, LcUCP1, LcAAC1, and, LcSnRK2) reached their peak within the initial 24 h of storage, accompanied by an elevation in the respiratory rate, which effectively suppressed the rise in browning index of litchi pericarp. The study also posits that, to cope with the decrease of energy levels and membrane damage, litchi may augment the concentrations of fructose, glucose, inositol, galactose, and sorbose, thus safeguarding the canonical metabolic functions of the fruit. Collectively, these findings suggest that litchi can modulate energy and sugar metabolism to cope with fruit senescence under conditions of energy deficiency. This study significantly advances the understanding of the physiological responses exhibited by litchi fruit to post-harvest external stressors.

During the ripening of litchi (Litchi chinensis Sonn.) fruit, anthocyanin biosynthesis is crucial in providing vibrant coloring. Previous studies on anthocyanin-related transcription factors have made significant discoveries relating to plants. However, the role of the SQUAMOSA promoter-binding protein-like (SPL) transcription factors in anthocyanin biosynthesis has rarely been studied in litchi. SPL genes are widely involved in the developmental mechanisms of plants. In this study, a total of 17 SPL genes have been identified from the litchi genome. Phylogenetic analysis revealed that these genes were divided into eight groups (Group I-VIII). Analysis of gene structure conserved domains, conserved motifs, and miR156 target prediction showed that LcSPLs were highly conserved during evolution. RNA-seq analysis of litchi revealed that six LcSPL genes have a role in regulating anthocyanin biosynthesis. Further, weighted correlation network analysis (WGCNA) revealed LcSPL7’s role in anthocyanin synthesis and chlorophyll degradation in litchi fruit ripening. These findings collectively suggest that the LcSPL gene family plays an essential role in anthocyanin biosynthesis in litchi pericarp. In summary, comprehensive bioinformatics analysis of the SPL family expands our understanding of anthocyanin synthesis in litchi pericarp.

Obtaining consistent multi-view images of litchis is crucial for various litchi-related studies, such as data augmentation and 3D reconstruction. This paper proposes a two-stage model that integrates the Mask2Former semantic segmentation network with the Wonder3D multi-view generation network. This integration aims to accurately segment and extract litchis from complex backgrounds and generate consistent multi-view images of previously unseen litchis. In the first stage, the Mask2Former model is utilized to predict litchi masks, enabling the extraction of litchis from complex backgrounds. To further enhance the accuracy of litchi branch extraction, we propose a novel method that combines the predicted masks with morphological operations and the HSV color space. This approach ensures accurate extraction of litchi branches even when the semantic segmentation model’s prediction accuracy is not high. In the second stage, the segmented and extracted litchi images are passed as input into the Wonder3D network to generate multi-view of the litchis. After comparing different semantic segmentation and multi-view synthesis networks, the Mask2Former and Wonder3D networks demonstrated the best performance. The Mask2Former network achieved a mean Intersection over Union (mIoU) of 79.79% and a mean pixel accuracy (mPA) of 85.82%. The Wonder3D network achieved a peak signal-to-noise ratio (PSNR) of 18.89 dB, a structural similarity index (SSIM) of 0.8199, and a learned perceptual image patch similarity (LPIPS) of 0.114. Combining the Mask2Former model with the Wonder3D network resulted in an increase in PSNR and SSIM scores by 0.21 dB and 0.0121, respectively, and a decrease in LPIPS by 0.064 compared to using the Wonder3D model alone. Therefore, the proposed two-stage model effectively achieves automatic extraction and multi-view generation of litchis with high accuracy.

The ‘Feizixiao’ litchi cultivar, predominantly grown in Hainan Province, faces the issue of “sugar receding” during fruit ripening. The application of mixed foliar nutrients containing calcium and magnesium (Ca+Mg) during the fruit pericarp’s full coloring stage was investigated to overcome this issue. Experimental trials unveiled significant alterations in litchi pulp physiochemical properties, including the main nutrient and flavor quality, the total respiration rates of the main respiratory pathways, and the activities of some important enzymes associated with Embden–Meyerhof–Parnas (EMP), the tricarboxylic acid cycle (TCA) and the pentose phosphate pathway (PPP). The Ca+Mg treatment showed higher sugar levels than the control (CK) during ripening. Notably, the application of Ca+Mg in litchi pulp inhibited respiration rates through the EMP, TCA, and PPP pathways, resulting in a strong effect. RNA sequencing analysis revealed the impact of Ca+Mg treatment on respiratory pathways, revealing differentially expressed genes (DEGs) such as pyruvate PK1, PK2 (pyruvate kinase), and PDC (pyruvate dehydrogenase complex), validated through qRT-PCR with a significant correlation to RNA-seq results. In general, Ca+Mg treatment during litchi fruit ripening overcame “sugar receding” by inhibiting the expression of respiration key metabolic pathway genes. These findings provide insights for enhancing cultivation management strategies.

Class III peroxidases (CIII PRXs) are plant-specific enzymes with high activity that play key roles in the catalysis of oxidation-reduction reactions. In plants, CIII PRXs can reduce hydrogen peroxide to catalyze oxidation–reduction reactions, thereby affecting plant growth, development, and stress responses. To date, no systematic analysis of the CIII PRX gene family in litchi (Litchi chinensis Sonn.) has been documented, although the genome has been reported. In this study, a total of 77 CIII PRX (designated LcPRX) gene family members were predicted in the litchi genome to provide a reference for candidate genes in the responses to abiotic stresses during litchi growth and development. All of these LcPRX genes had different numbers of highly conserved PRX domains and were unevenly distributed across fifteen chromosomes. They were further clustered into eight clades using a phylogenetic tree, and almost every clade had its own unique gene structure and motif distribution. Collinearity analysis confirmed that there were eleven pairs of duplicate genes among the LcPRX members, and segmental duplication (SD) was the main driving force behind the LcPRX gene expansion. Tissue-specific expression profiles indicated that the expression levels of all the LcPRX family members in different tissues of the litchi tree were significantly divergent. After different abiotic stress treatments, quantitative real-time PCR (qRT-PCR) analysis revealed that the LcPRX genes responded to various stresses and displayed differential expression patterns. Physicochemical properties, transmembrane domains, subcellular localization, secondary structures, and cis-acting elements were also analyzed. These findings provide insights into the characteristics of the LcPRX gene family and give valuable information for further elucidating its molecular function and then enhancing abiotic stress tolerance in litchi through molecular breeding.

Efforts to enrich the varietal wealth in litchi with desired cultivars have been attempted. At ICAR-NRCL hybridization efforts have been emphasized for the past decades. The observed characteristic features and constraints encountered during the period were identified and systematic observations were taken. Studies show that the low genetic variability, small window of flowering period and stigma receptivity, small flower size, panicle injury, high flower and fruit drop, low seed germination and survivability are the prime hurdle that needs to be addressed. On average, the flowering period reported is 10–14 days which is even shorter during periods of increasing weather temperature. Across cultivars, the effective pollination period is very narrow and coincidence of stigma receptivity among cultivars was observed making it very challenging to attempt a maximum number of crosses within a short period. It was also observed that large numbers of small-sized and delicate flowers are produced in a panicle which injure the panicles during thinning and emasculation. Less than 3% of pollinated flowers were observed to attain fruit set which also registered low fruit retention during subsequent fruit development. The attack of seed borer at both the early and mature stages of fruit growth was noted which rendered the seeds non-viable. Parent incompatibility and very low success rate of hybrid seedling establishment were also observed especially in crosses involving small seeded parents like 'Bedana'. Here we present findings from a decade of experimentation on hybridization in litchi and document hurdles that come in the way of developing hybrids in litchi. Such information will be crucial for devising strategies for an effective litchi breeding programme. [ABSTRACT FROM AUTHOR]

Litchi is one of the nutritionally rich and economically significant fruit of Indian subcontinent. With the advent of Good Management Practices (GMPs), litchi farming technology has advanced drastically. The study was conducted in 2022 in the Muzaffarpur district of Bihar to assess the level of knowledge and adoption of GMPs among litchi farmers and their relationship with the socio-economic profile of litchi growers. The primary data were personally collected through a well-structured interview schedule from 120 respondents. Knowledge and adoption were determined, practicewise on 19 different parameters of GMPs. The highest number of litchi growers (77.50%) had a medium level of knowledge while 71.67 per cent had a medium adoption level of the recommended GMPs in litchi production. Variables viz., the area under litchi, cosmopolitness, farming experience, risk preference, innovativeness, and attitude towards GMPs were positively and significantly related to knowledge as well as adoption. Primary work and education were positively and significantly related to adoption. Dissemination of information about modern agricultural practices is necessary for the adoption of GMPs in litchi production. [ABSTRACT FROM AUTHOR]

Polyphenols called procyanidins can be extracted from agro-industrial waste like litchi peel and coffee pulp. However, their efficacy is limited due to instability, which hinders both the bioavailability and preservation of their activity. This study aims to establish the ideal encapsulation conditions required to preserve the procyanidin properties found in extracts taken from litchi peel and coffee pulp. To attain the maximum procyanidin encapsulation efficacy (EE), the Taguchi method was utilized to streamline the spray-drying conditions for different wall materials—maltodextrin (MD), whey protein (WP), citrus pectin (CP), and skim milk (SM). The optimized conditions consisted of feed flow (3, 4.5, and 6 mL/min), temperature (125, 150, and 175 °C), and airflow (30, 35, and 40 m3/h). The microcapsules were characterized using ABTS, DPPH, lipoperoxidation, and scanning electron microscopy. Objective evaluations revealed that MD was the most effective encapsulation material for the litchi extract, whereas WP was the optimal option for the coffee extract. Of all the factors considered in the spray-drying process, feed flow had the strongest impact. The spray-drying process for the litchi peel extracts achieved high procyanidin encapsulation efficiencies at a feed flow rate of 4.5 mL/min, a temperature of 150 °C, and an airflow rate of 35 m3/h. Meanwhile, the coffee extract spray drying achieved similar results at a feed flow rate of 4.5 mL/min, a temperature of 175 °C, and an airflow rate of 40 m3/h. Encapsulation efficiencies of 98.1% and 93.6% were observed for the litchi and coffee extracts, respectively, under the mentioned optimal conditions. The microencapsulation process was successful in preserving the antioxidant properties of procyanidins. The microcapsules' size ranged from 2.6 to 3.2 micrometers. The results imply that the phenolic compounds present in the extracts function as effective antioxidant agents. [ABSTRACT FROM AUTHOR]

The automated harvesting of clustered fruits relies on fast and accurate visual perception. However, the obscured stem diameters via leaf occlusion lack any discernible texture patterns. Nevertheless, our human visual system can often judge the position of harvesting points. Inspired by this, the aim of this paper is to address this issue by leveraging the morphology and the distribution of fruit contour gradient directions. Firstly, this paper proposes the calculation of fruit normal vectors using edge computation and gradient direction distribution. The research results demonstrate a significant mathematical relationship between the contour edge gradient and its inclination angle, but the experiments show that the standard error projected onto the Y-axis is smaller, which is evidently more conducive to distinguishing the gradient distribution. Secondly, for the front view of occluded lychee clusters, a fully convolutional, feature prototype-based one-stage instance segmentation network is proposed, named the lychee picking point prediction network (LP3Net). This network can achieve high accuracy and real-time instance segmentation, as well as for occluded and overlapping fruits. Finally, the experimental results show that the LP3Net based on this study, along with lychee phenotypic features, achieves an average location accuracy reaching 82%, significantly improving the precision of harvesting point localization for lychee clusters. [ABSTRACT FROM AUTHOR]

[Objective]By comparing the differences in cell wall components among litchi varieties with different susceptibility to fruit cracking, the study aims to investigate the effects of exogenous application of auxin analogue 2,4-D on the cell wall composition of pericarp and fruit cracking, and to further explore the relationship between the cell wall synthesis metabolism and fruit cracking incidence.[Methods]The changes in carbohydrate contents of two easily cracked litchi varieties (‘Guiwei’ and ‘Nuomici’) and two not easily-cracked litchi varieties (‘Huaizhi’ and ‘Lingfengnuo’) after 75 days of flowering were compared, and the tissue structure and lignin distribution of the pericarps at the 60-85 d after flowering were observed. Fruit clusters of ‘Nuomici’ in two orchards were dipped into auxin analog 2, 4-D, and the soluble sugar contents in the pericarps were determined by GC-MS. The starch and structural carbohydrate contents of the samples were detected by using a spectrophotometer. Transmission electron microscopy and lignin staining were used to observe the tissue structure of litchi pericarp.[Result]The contents of hexose including fructose, glucose and galactose in the pericarp of cracking susceptible variety ‘Nuomici’ were significantly lower than those of low-cracking varieties ‘Huaizhi’ and ‘Lingfengnuo’. A complicate relationship between pectin contents and fruit cracking susceptibility was found. In the pericarp of ‘Nuomici’, the pectin content was only around 1.7 mg/g. And the fruit was bigger and susceptible to cracking. While in the cracking susceptible smaller fruit variety ‘Guiwei’, the pericarp contained high pectin (4.0 mg/g). 2,4-D treatment only temporarily increased the fruit setting rate of litchi in the early stage, but it had no significant impact on the final fruit setting rate. 2,4-D treatment could lead to an increase in the number of layers of pericarp cells and the blurring of the contour of inner pericarp cells; Compared with the control, the treatment with 40 mg/L 2,4-D resulted in an increase in pectin content, thickening of cell walls, and an increase in fruit cracking rate.[Conclusion]There are significant differences in the contents of carbohydrates in the pericarps of litchi varieties with different susceptibility to fruit cracking. Pectin may play a dual role in litchi fruit cracking. The development of pericarp requires dynamic changes in pectin synthesis and degradation. Pectin might play dual role in the cracking of litchi fruit. High pectin in the pericarp results in low expansion, smaller fruit size and higher cracking rate; while low pectin results in higher pericarp expansion, larger fruit size and higher cracking rate. 2,4-D treatment show no significant effect on the final fruit setting rate but will increase the risk of fruit cracking. [ABSTRACT FROM AUTHOR]

[Objective]This study aims to discover members of the Al-activated malate transporter ALMT gene family that may be involved in the growth and development of litchi and to investigate their biological functions.[Method] The physicochemical properties of proteins, subcellular localisation predictions, phylogeny, gene structure, conservative motifs, chromosomal positioning, promoter cis-acting elements, protein structure and expression patterns of litchi ALMT gene family members were systematically analysed using bioinformatics methods, expression of the litchi LcALMTs was analysed by qPCR.[Result]The results showed that the litchi LcALMT gene family has 16 members with CDS lengths ranging from 118 to 803 bp and isoelectric points between 5.16 and 9.07. Subcellular localisation predictions showed that the LcALMTs were all localised to the plasma membrane, and the family was divided into five subclades based on a phylogenetic tree. The number of exons of the LcALMTs ranged from 3 to 10, and four LcALMT genes did not contain any non-coding regions. Chromosomal localisation analysis revealed that LcALMTs was localised on only six of the 15 chromosomes of litchi, and mainly on chromosome 13. Conservative motif analysis revealed that litchi ALMT family members contain both ALMT and ALMT superfamily structural domains. Among the cis-acting elements, light-responsive elements accounted for the largest proportion, followed by hormone-responsive elements. Expression pattern analysis revealed that the expression of Litchi LcALMTs was highly variable in different tissues, with LcALMT5 and LcALMT15 being expressed at high levels in all tissues, the qPCR results showed that the expression level of LcALMT5 was more consistent with the results of the transcriptome.[Conclusion] There are 16 members of the litchi ALMT Gene family, which has a conservative gene structure and protein domain, and there are differences in tissue expression. [ABSTRACT FROM AUTHOR]

[Objective]Zengcheng has a long history of planting litchi, and is one of the high-quality litchi producing areas in Guangdong, therefore it is of great significance to systematically collect, identify and evaluate their germplasm resources. [Method]A systematically investigation was conducted on the local litchi resources and ancient litchi resources in six villages in Zengcheng District, Guangzhou, Guangdong Province.[Result]Information of a total of 160 individual plants was collected, including 45 litchi seedlings, and the fruit characters of 26 fruiting trees were analyzed and evaluated. The results showed that the seeds of litchi seedlings were mostly full, with low wilted-nut rate (below 25%), low edible rate (below 75%), sour taste and morerately small fruits. However, six representative litchi germplasm resources with high specificity or comprehensive quality were screened out, and their fruits had the characteristics of high wilted-nut rate (93%), long treekeeping period, early ripening period, purple peel, strong fragrance and special taste, indicating that there were germplasm resources with excellent comprehensive characteristics and specificity in Zengcheng, Guangdong. In regard to the investigation of ancient trees,18 representative sample sites were selected for systematic investigation, and biological characteristics of 115 ancient litchi trees were collected, and their habitat distribution characteristics and productivity were analyzed. The results showed that the fruit types of ancient trees are relatively single, and the main high-quality varieties were ‘Nuomici’, ‘Guiwei’ and ‘Huaizhi’. The maximum height of the tree was 25 m, the average height was 9.8 m, the maximum trunk girth was 410 cm, the average trunk girth was 220 cm, and the average crown width was 11.5 m× 12.0 m from north to south. It was speculated that the ages of ancient litchi trees in Lanxi, Zengcheng were mostly between 100 years and 500 years, and the oldest was not more than 1 000 years. The ancient trees showed good yield performance, and the yields distributed in the downhill foothills and plains were high, most with 100 kg, up to a maximum of 300 kg.[Conclusion]Based on the investigation of litchi germplasm resources in Lanxi, Zengcheng, Guangdong Province, six specific or excellent seedling litchi germplasm resources are identified and evaluated according to their fruit characteristics, and the survival status and age of ancient litchi resources are analyzed, and relevant suggestions on resource protection and utilization are put forward. The research results can provide references for exploration and innovative application germplasm resources in Zengcheng, Guangdong Province. [ABSTRACT FROM AUTHOR]

【Objective】This study aimed to investigate and analyze the correlation between the quality of fruitbearing shoots in ‘Xianjinfeng’ litchi and fruit setting and fruit quality. Tthe effects of different quality fruit-bearing shoots on fruit setting and quality were compared. The quantitative standard of high quality fruit branches was put forward to provide reference for the development of strong fruit branches in production.【Method】During the key phenological period, the quality indicators of fruit-bearing shoots in ‘Xianjinfeng’ litchi, including length, diameter, and number of leaves, were measured and statistically analyzed. Number of initial fruit setting and final fruit setting with fruit quality were also assessed. Violin plots, Pearson correlation coefficients, and one-way ANOVA were utilized to analyze the distribution, correlation, and significance of the data, as well as to compare the differences in fruit setting and quality among fruit-bearing shoots of different qualities.【Result】The length, diameter, and number of leaves of fruit-bearing shoots in ‘Xianjinfeng’ litchi were concentrated within the ranges of 10.2-14.5 cm, 0.4-0.5 cm, and 28-38 leaves, respectively. The number of initial fruit setting exhibited a significant positive correlation with the diameter of the mother branches, while the final fruit setting rate showed a significant positive correlation with both length and diameter. The correlation between the length, diameter, and number of leaves of fruit-bearing shoots and the same fruit quality traits was generally consistent, either positively or negatively correlated. Notably, single fruit weight demonstrated a significant positive correlation with diameter, while TSS (Total Soluble Solids) and TSS/TA (Total Soluble Solids/Titratable Acidity) showed a significant positive correlation with the number of leaves. Fruit-bearing shoots with a length greater than 14.5 cm exhibited the highest initial fruit setting number (16.95 fruits) and final fruit setting rate (20.73%). Fruit-bearing shoots with a diameter greater than 0.5 cm exhibited the highest initial fruit setting number (15.48 fruits), final fruit setting rate (28.03%), single fruit weight (26.28 g), and edible rate (70.95%). Fruit-bearing shoots with more than 38 leaves exhibited the highest TSS (18.36%) and TSS/TA (250.81).【Conclusion】Based on the findings, a robust standard for fruit-bearing shoots in 'Xianjinfeng' litchi was determined as having a length greater than 14.5 cm, diameter greater than 0.5 cm, and number of leaves greater than 38. [ABSTRACT FROM AUTHOR]

Litchi inflorescences bear hundreds of small flowers, but most flowers need to be removed to reduce the consumption of carbohydrates and increase fruit setting. The production and secretion of nectar are largely affected by the availability and metabolism of carbohydrates. However, the secretion pattern and constituents of litchi nectar in response to the removal of inflorescences are unclear. Here, we showed that the litchi nectar secretion amount ranged from 4 to 10 mg per flower with the cultivar 'Nuomici' having the strongest secretion ability. The concentration of total soluble solids in litchi nectar was approximately 30%. Fructose was present in the highest concentration in nectar, followed by glucose and sucrose. Cultivar, flower sex and inflorescence-removal treatment had no significant main effect on soluble sugars but had two-way interaction effects on sucrose. Twenty-seven amino acids were detected, including seven essential amino acids. The concentration of amino acids was significantly affected by cultivar and flower sex, with nectar from the cultivar 'Guiwei' and male flowers having a significantly higher concentration. Removal of inflorescences did not show the main effect on the nectar amount, total soluble solids, or protein contents, but had interactive effects on the concentration of sucrose and amino acids. [ABSTRACT FROM AUTHOR]

This study aimed to assess the occurrence of eight heavy metals in lychee (Litchi chinensis Sonn.) fruit samples collected from orchards of the Dehradun and Haridwar districts in Uttarakhand, India. Lychee fruit samples were collected from ten (10) sampling locations from May to June 2023 and analyzed using inductively coupled plasma optical emission spectroscopy (ICP-OES). Results showed that lychee fruit samples showed varying levels of selected heavy metals, i.e., Cd (0.009–0.095 mg/kg), Cr (0.079–0.960 mg/kg), Cu (0.095–0.258 mg/kg), Fe (0.254–0.531 mg/kg), Pb (0.000–0.011 mg/kg), Mn (0.862–1.903 mg/kg), Ni (0.166–0.310 mg/kg), and Zn (0.076–0.149 mg/kg). It was observed that lychee fruit sampling sites near urban and industrial areas had higher concentrations of heavy metals as compared to those in rural and agricultural areas. In addition, principal component analysis (PCA) and clustered heatmap dendrogram results showed that several sites had significant similarities in terms of heavy metal availability. Overall, the levels of all heavy metals were below the safe limits as suggested by health risk studies. The selected indices such as daily intake of metals (DIM), health risk index (HRI), and target hazard quotient (THQ) did not exceed the standard limit which indicated consumption of lychee fruit was safe at all sampling sites. The results of this study emphasize the need to regularly monitor lychee heavy metal levels and implement sustainable agricultural and environmental practices to reduce contamination sources. [ABSTRACT FROM AUTHOR]

WRKY proteins comprise a large family of transcription factors that play important roles in plant growth, development, and responses to stress, but little information is available about these genes in lychee (Litchi chinensis Sonn.). Despite being a popular fruit worldwide, lychee is highly vulnerable to lychee downy blight (LDB; caused by Peronophythora litchii), a major disease affecting lychee. Based on lychee whole‐genome data, a total of 50 LcWRKY genes were identified across 15 chromosomes. According to a conserved domain and phylogenetic analysis, these 50 LcWRKYs were classified into three distinct subfamilies. Gene structure analysis revealed the presence of 2–11 exons in the LcWRKYs. Cis‐acting regulatory element analysis identified many stress‐response elements in LcWRKY promoters. Moreover, a comprehensive 2‐year investigation involving the screening of a lychee natural population led to the identification of Guiwei and Yurong1 as displaying stable susceptibility and resistance against LDB, respectively. Furthermore, expression patterns indicated that LcWRKY13, LcWRKY17, and LcWRKY34 were significantly upregulated in response to LDB induction, while LDB suppressed the expression of LcWRKY11. These findings suggest that these four genes may play a crucial role in lychee resistance to LDB. The present study has provided a foundation for future investigations of LcWRKY gene function in lychee. Core Ideas: The WRKY family was fully characterized by bioinformatics in lychee.Lychee downy blight (LDB) caused by Peronophythora litchii is one of the major diseases of lychee.One natural population consisting of 276 lychee landraces was screened for LDB resistance.Four WRKY genes that may be critical in lychee resistance to LDB were selected for further genomic studies. [ABSTRACT FROM AUTHOR]

The effects of dimethyl dicarbonate (DMDC), mild heat and their combination on the microorganisms and physicochemical indices of litchi juice were compared. The results showed that the sterilization effect of DMDC alone or mild heat alone was poor, whilst the number of residual microorganisms in the litchi juice treated by the combination was the lowest, with the total number of colonies and lactic acid bacteria being 0.41 and 0.36 lg CFU/mL, respectively, and no yeast and mold being detected. Compared to fresh litchi juice, DMDC treatment had no effect on the quality of Litchi juice, and the changes in ascorbic acid content and color of the mild heat alone group and the combined treatment group were insignificant, causing the increases in the total phenolics (total flavonoids) by 40.16% (7.16%) and 38.01% (4.35%), respectively, and increases in the ferric ion reducing antioxidant power (DPPH free radical scavenging ability) by 15.55% (11.85%) and 7.61% (3.71%), respectively. These results indicated that mild heat could promote the release of phenolics and improve the antioxidant activity. Correlation analysis showed that the ΔE of litchi juice was negatively correlated with Vc content, and the antioxidant activity was positively correlated with the contents of total phenolics and total flavonoids. Cluster heat map analysis and sensory evaluation revealed that the combined treatment could promote the release of flavor substances without causing a pronounced cooking flavor. The total number of colonies in the combined treatment group stored at 4 °C for 21 days was less than 100 CFU/mL. In conclusion, the combination of mild heat and DMDC treatment led to a good sterilization effect on the microorganisms in the litchi juice without causing adverse effects, and the shelf life of the juice was up to 21 d. This study provides a scientific basis for the industrialization of high-quality litchi juice. [ABSTRACT FROM AUTHOR]

Lychee plantation areas are typically located at varying elevations on mountains to ensure proper drainage. This placement has direct effects on stream and river water flows and consequently influences pesticide residue, water quality and aquatic biodiversity. This research aims to examine the relationships between cypermethrin residue, water quality and phytoplankton diversity in the lychee plantation catchment area in Phayao Province, Thailand, from January to May 2022. The study area was divided into six sampling sites. Water samples were collected for the investigation of cypermethrin residual, physicochemical and biological water quality parameters. The water quality index was used as an overall measurement of water quality. The study also examined the diversity of phytoplankton species and the relationship among cypermethrin residue, water quality and phytoplankton diversity were studied using canonical correspondence analysis. The findings revealed an increasing trend of cypermethrin residue, with the maximum concentration reaching 29.43 mg/L in March. The trend of decreasing water quality scores from Station S1 to Station S5 indicated the influence of land use changes and human activities, especially in the community area (S5), which was characterized by deterioration of water quality. A total of 174 phytoplankton species were categorized into 5 divisions, with Chlorophyta accounting for 61.49% of the total, followed by Bacillariophyta (28.16%) and Cyanophyta (6.32%). The highest Shannon's diversity index and evenness were observed at Stations S3 and S4, respectively. The canonical correspondence analysis revealed an interesting relationship among cypermethrin residue, ammonia nitrogen, chlorophyll a and three algal species: Pediastrum simplex var. echinulatum, Pediastrum duplex var. duplex and Scenedesmus acutus at Station S3. This research implies that pesticide residue and water quality have a direct impact on phytoplankton distribution, illustrating the environmental challenges that occur in various geographical areas. This information can be applied to assist in the development of future sustainable land use management initiatives. [ABSTRACT FROM AUTHOR]

The utilization of unmanned aerial vehicles (UAVs) for the precise and convenient detection of litchi fruits, in order to estimate yields and perform statistical analysis, holds significant value in the complex and variable litchi orchard environment. Currently, litchi yield estimation relies predominantly on manual rough counts, which often result in discrepancies between the estimated values and the actual production figures. This study proposes a large-scene and high-density litchi fruit recognition method based on the improved You Only Look Once version 5 (YOLOv5) model. The main objective is to enhance the accuracy and efficiency of yield estimation in natural orchards. First, the PANet in the original YOLOv5 model is replaced with the improved Bi-directional Feature Pyramid Network (BiFPN) to enhance the model's cross-scale feature fusion. Second, the P2 feature layer is fused into the BiFPN to enhance the learning capability of the model for high-resolution features. After that, the Normalized Gaussian Wasserstein Distance (NWD) metric is introduced into the regression loss function to enhance the learning ability of the model for litchi tiny targets. Finally, the Slicing Aided Hyper Inference (SAHI) is used to enhance the detection of tiny targets without increasing the model's parameters or computational memory. The experimental results show that the overall A P value of the improved YOLOv5 model has been effectively increased by 22%, compared to the original YOLOv5 model's A P value of 50.6%. Specifically, the A P s value for detecting small targets has increased from 27.8% to 57.3%. The model size is only 3.6% larger than the original YOLOv5 model. Through ablation and comparative experiments, our method has successfully improved accuracy without compromising the model size and inference speed. Therefore, the proposed method in this paper holds practical applicability for detecting litchi fruits in orchards. It can serve as a valuable tool for providing guidance and suggestions for litchi yield estimation and subsequent harvesting processes. In future research, optimization can be continued for the small target detection problem, while it can be extended to study the small target tracking problem in dense scenarios, which is of great significance for litchi yield estimation. [ABSTRACT FROM AUTHOR]

Lychee seeds (LS) and longan seeds (LoS) are excellent sources of phenolic compounds (PCs) with strong antioxidant activity (AOA). The aim of this study was to optimize the extraction conditions regarding extraction yield (EY), extractable phenolic compound (EPC), and AOA from LS and LoS using surface response methodology (RSM). Solvent concentration, extraction temperature, time, and solid to liquid ratio were optimized using RSM. Increasing the solid to solvent ratio from 1:05 to 1:40 (w/v), increased EY for LoS, however, EY did not change from 1:20 to 1:40 for LS. Solid–liquid ratio 1:20 was chosen for this study. Increasing the quantity of solvent leads to higher EPC and FRAP. The results showed that LoS exhibited higher AOA than LS measured as DPPH, ABTS, and FRAP, respectively. Ethanol concentrations and temperatures significantly (p < 0.05) affect EY, EPC, and AOA. The results (R2 > 0.85) demonstrated a good fit to the suggested models and a strong correlation between the extraction conditions and the phenolic antioxidant responses. The ethanol concentrations of 41 and 53%, temperatures of 51 and 58 °C, and the corresponding times of 139 and 220 min were the optimal conditions that maximized the EY, EPC, and AOA from LS and LoS. [ABSTRACT FROM AUTHOR]

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【Objective】Determination of the high-yield production level is the premise of establishing foliar nutrient diagnosis indicators for crop. The problems of compositional nutrient diagnosis (CND) approach in determining the high-yield levels of litchi and longan were examined, with the aim to identify whether CND is a suitable approach for diagnosis of foliar nutrient in litchi and longan.【Method】A total of 511 leaf samples of litchi (Litchi chinensis Sonn) (c.v. Feizixiao) and 262 leaf samples of longan (Dimocarpus longan Lour) (c.v. Chuliang) were collected at terminal shoot maturing stage and fruit bulking stage in litchi and longan orchards in South China during 2016-2019. The fruit yields of all sample trees were recorded at each harvest period. Foliar nutrient (N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn and B) contents in all samples were determined. Based on the principle of CND approach, the models for the accumulative variance function of foliar nutrient content and fruit yield of litchi and longan were fitted. The appearance of anomalous extremes was examined, and their effects on the models were further analyzed. Then, the variations of the cutoff values before and after the elimination of anomalous extremes were compared, and the influences of different high-yield cutoff value selection principles on high-yield population were investigated.【Result】Abnormal values appeared in the models for fruit yield of both litchi and longan at different growth periods. The removal of the abnormal values had significant influence on the yield models and nutrient cutoff values, and the influence was irregular. No matter what kind of principle is used to determine the high-yield threshold, there were problems such as the small size of the high-yield population, the low proportion of high-yield population or the great discrepancy between the calculated yield level and the actual yield level. Moreover, the calculated high-yield threshold considerably varied with growth stage and year, indicating poor stability. In addition, there was a strong subjectivity in the treatment of abnormal values and the selection of high-yield threshold.【Conclusion】There are obvious shortcomings when CND approach is adopted to determine the high-yield population. The obstacles are probably ascribed to the joint restrictions of the sample size, the foliar nutrient content, and the counting scale of the present study. Therefore, the suitability of CND approach for foliar nutrient diagnosis in perennial woody fruit trees with alternative fruit bearing needs to be carefully evaluated.

The study aims to explore the development status, trends and shortcomings of the litchi industry in the mainland of China under the new situation, and to propose corresponding countermeasures to enhance farmers' income and facilitate the high-quality development of litchi industry in the future. By using comparative analysis, the production scale and market situation of litchi in the mainland of China in 2021 and 2022 were compared, and the status and trend of industrial development were analyzed. The results showed that, in 2022, the cultivated area of litchi in the mainland of China remained basically stable at about 526 073.33 hm2; total output was 2 222 700 t, decreasing by 21.02% year-on-year but still keeping at a medium to high level; market demand continued to be strong and on the rise; import and export trade of litchi and products from January to August 2022 was US 839 700, decreasing by 20.02% year-on-year; the average yield per hectare of litchi was 5 176.65 kg, declining by 9.82% compared with that of 2021; the total output value of litchi was approximately 35.392 billion yuan with an increase of 46.52% year-on-year. Green, quality, distinctive and branded litchi industry for high quality and sustainable development, must be laid out from the perspective of the whole industry chain, good top-level design, consolidation of the institutional environment, improvement of the market demand-oriented industry chain integration system, science and technology to empower the sustainable development of the industry, enhancement of industrial development supporting services support system, and construction of industrial data integration and information sharing.

【Objective】In regard to the problems including excessive chemical fertilizer application and serious soil quality decline in litchi orchards in Guangdong Province, and the urgent need of resource utilization of manure produced by the surrounding large-scale livestock and poultry breeding, the effects of fertilizer reduction combined with organic fertilizer on growth and rhizosphere microorganisms of litchi were studied, aiming to provide fertilization references for the scientific planting of litchi in Guangdong Province.【Method】'Guiwei' litchi was used as the research material. Six treatments were set: no fertilization (CK), chemical fertilizer application (CF), fertilizer reduction by 30%, and combined application of pig manure organic fertilizer of 5 kg/plant (OF5), 10 kg/plant (OF10), 15 kg/plant (OF15), and 20 kg/plant (OF20). The relative indicators of enzyme activity of litchi rhizosphere soil, number of culturable microorganisms, microbial biomass, yield and quality under different treatments were compared.【Result】The results showed that compared with the CF treatment, when the chemical fertilizer application was reduced by 30%; Under the OF15 treatment, the invertase activity and urease activity of rhizosphere soil were increased by 35.3% and 25.6%, the number of actinomyces increased by 18.1%, and the microbial biomass nitrogen increased by 23.6%; Under the OF10 treatment, the phosphatase activity was increased by 32.2%, the number of fungi increased by 14.4%, the microbial biomass carbon increased by 26.1%; Under OF20 treatment, the number of culturable bacteria was increased by 11.8%. The application of organic fertilizer could significantly improve the quality and yield of litchi. Compared with the single application of chemical fertilizer, the yields under OF5, OF10, OF15 and OF20 treatments increased by 7.15%, 10.64%, 13.75% and 13.32%, respectively.【Conclusion】In conclusion, the application of 10kg-15kg pig manure organic fertilizer with chemical fertilizer reduced by 30% could significantly improve the quality and efficiency.

D-arginine (D-Arg) can promote embryogenic callus (EC) proliferation and increase the rate of somatic embryo induction of litchi (Litchi chinensis Sonn.), yet the mechanism underlying the processes is incompletely understood. To investigate the mechanism, physiological responses of polyamines (PAs) [putrescine (Put), spermidine (Spd), and spermine (Spm)] were investigated for D-Arg-treated litchi EC and enzyme activity related to polyamine metabolism, plant endogenous hormones, and polyamine- and embryogenic-related genes were explored. Results showed that the exogenous addition of D-Arg reduces the activity of diamine oxidase (DAO) and polyamine oxidase (PAO) in EC, reduces the production of H2O2, promotes EC proliferation, and increases the (Spd + Spm)/Put ratio to promote somatic embryo induction. Exogenous D-Arg application promoted somatic embryogenesis (SE) by increasing indole-3-acetyl glycine (IAA-Gly), kinetin-9-glucoside (K9G), and dihydrozeatin-7-glucoside (DHZ7G) levels and decreasing trans-zeatin riboside (tZR), N-[(-)-jasmonoyl]-(L)-valine (JA-Val), jasmonic acid (JA), and jasmonoyl-L-isoleucine (Ja-ILE) levels on 18 d, as well as promoting cell division and differentiation. The application of exogenous D-Arg regulated EC proliferation and somatic embryo induction by altering gene expression levels of the WRKY family, AP2/ERF family, C3H family, and C2H2 family. These results indicate that exogenous D-Arg could regulate the proliferation of EC and the SE induction of litchi by changing the biosynthesis of PAs through the alteration of gene expression pattern and endogenous hormone metabolism.

Litchi and longan are tropic/subtropic fruits harboring recalcitrant seeds that are covered with sugar-rich arils as the edible part. A rapid sugar content decline, called sugar receding, in the arils after the fruit maturation largely reduces the fruit quality, however, the mechanism is unclear. Litchi and longan fruits grow and mature in a hot and rainy season with dry spells between rainfalls. Here, we found that the seed maturation was around 2 weeks earlier than the fruit maturation, after which the sugar contents of the arils significantly decreased, while the fruits could stay on the tree for 1–2 months with high seed vigor. A continuously low-level fruit drop after the seed maturation resulted in continuous seed germination and seedling establishment in around 2–3 months. Blocking assimilate supply by storage of detached fruits or on-tree girdling-plus-defoliation for 7 days, the aril sugar contents of the treated fruits significantly decreased, while the sugar levels and vigor of the seeds increased, implying that the arils are sugar sources to maintain or even enhance the seed vigor and suggesting that sugar receding in arils benefits the recalcitrant seeds of litchi and longan to cope with dry spells after maturation.

Manganese toxicity is a major obstacle to agriculture in acid soils. Dark pericarp disease (DPD) is a newly spread physiological disorder induced by excess Mn in litchi, leading to undesirable fruit appearance and substantial economic loss. In this work, broadcast of alkaline soil conditioner in winter, followed by foliar sprays of ascorbic acid and sulfur solution at fruit development, was adopted to examine the effect of these combinations on DPD alleviation in a litchi orchard, with DPD morbidities of 70~85% in recent ten years. The combination of soil conditioner broadcast and foliar water spray was used as the control. At harvest, DPD incidence was significantly decreased by sulfur spray (3.3 ± 1.0%) and slightly reduced by ascorbic acid spray (10.7 ± 8.0%) compared to the control (12.9 ± 7.6%). Soil pH and available Mn were significantly increased and reduced by the soil conditioner broadcast. Sulfur spray significantly inhibited Mn uptake but enhanced the accumulation of Mg, Ca, sugars and cyanidin-3-rutinoside in the pericarp, leading to improved fruit pigmentation. Antioxidase activities were regulated to resist Mn stress by sulfur spray. The spray of ascorbic acid could not mitigate DPD as expected, probably due to the dose used. Conclusively, this study provides a practicable approach to mitigate Mn phytoavailability in acid soils.

The MADS-box protein is an important transcription factor in plants and plays an important role in regulating the plant abiotic stress response. In this study, a total of 94 MADS-box genes were predicted in the litchi genome, and these genes were widely distributed on all the chromosomes. The LcMADS-box gene family was divided into six subgroups (Mα, Mβ, Mγ, Mδ, MIKC, and UN) based on their phylogenetical relationships with Arabidopsis, and the closely linked subgroups exhibited more similarity in terms of motif distribution and intron/exon numbers. Transcriptome analysis indicated that LcMADS-box gene expression varied in different tissues, which can be divided into universal expression and specific expression. Furthermore, we further validated that LcMADS-box genes can exhibit different responses to various stresses using quantitative real-time PCR (qRT-PCR). Moreover, physicochemical properties, subcellular localization, collinearity, and cis-acting elements were also analyzed. The findings of this study provide valuable insights into the MADS-box gene family in litchi, specifically in relation to stress response. The identification of hormone-related and stress-responsive cis-acting elements in the MADS-box gene promoters suggests their involvement in stress signaling pathways. This study contributes to the understanding of stress tolerance mechanisms in litchi and highlights potential regulatory mechanisms underlying stress responses.

Litchi tree is planted in several countries of the world for its juicy fruit. For the estimated total annual global litchi production of ~ 2.7 million tons, around ~ 0.54 million tons of seeds as well as a sizeable amount of skin are generated as waste. This renewable waste biomass can be effectively used as the feedstock for recovering energy and obtaining several value-added products. In the present work, the fuel and thermochemical characteristics and thermal degradation behavior of acid- and alkali-treated litchi seed biomass were systematically investigated and compared for the first time. The average and maximum rate of mass losses, peak temperature and pyrolysis factor had been evaluated to assess the reactivity of the treated biomass. It had been observed that acid and alkali treatments improved the higher heating value and changed the thermal degradation behavior. The thermogravimetric (TG)/differential thermogravimetric analysis (DTG) data obtained at the heating rates of 20, 25 and 30 °C min−1 were used to evaluate the kinetic and thermodynamic parameters using iso-conversional models of Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, Tang and Starink. The Criado method had been used to elucidate the prevailing thermal degradation reaction mechanisms at different fractional conversions. The average activation energy of the acid-treated biomass increased, and that of the alkali-treated biomass decreased compared to that of the untreated biomass. [ABSTRACT FROM AUTHOR]

The shortage of precooling equipment in litchi-producing regions could lead to a high loss rate and poor quality of litchis. It is urgent to develop a portable precooling device for litchi-producing regions. In this study, a novel spray hydrocooler with thermal energy storage (TES) was designed, fabricated, and tested. A simple mathematical model of TES capacity, the ice-on-coil thermal resistance, and refrigeration system was employed to determine the hydrocooler parameters. Then, the structure of the spray hydrocooler was designed. The maximum charging test was implemented with full TES capacity, and the litchi spray hydrocooling experiments were carried out at different charging times (3–6 h), spray flow rates (30–60 L min−1), and litchi loads (8–28 kg) with one-third TES capacity. Results showed that: (1) the spray hydrocooler allows for the rapid and effective precooling of litchis within 15 min after harvest; (2) the hydrocooler can precool 299 kg litchis with one-third TES storage, meeting the precooling requirements; (3) the effective TES capacity achieved 1.25 × 108 J at the maximum TES capacity of the hydrocooler, while the energy efficiency ratio (EER) is 2; (4) the precooling capacity was maximum and the average power consumption was minimum when the litchi load was 23 kg and the spray flow rate was 30 L min−1. Longer charging time is the most important factor in increasing the precooling capacity and reducing the average power consumption. It provides feasible precooling equipment for rapid precooling in litchi-production regions. [ABSTRACT FROM AUTHOR]

Lychee downy blight (LDB) is an oomycete pathogen (Peronophythora litchi) disease, which affects the fruits and leaves of lychee, resulting in economic losses. Chemical fungicides are commonly used for disease control, while for eco-safety measures, the study of molecular mechanisms involved in lychee resistance against LDB is necessary. Non-coding RNAs (ncRNAs), including long ncRNAs (lncRNAs), circular (circRNAs), and microRNAs (miRNAs), play a crucial role in plant disease resistance. To examine lychee response (fruits and leaves) to LDB, we studied the expression patterns of ncRNAs and mRNAs under LDB treatment. By whole transcriptome sequencing analyses, a total of 36,885 mRNAs, 2627 lncRNAs, 4682 circRNAs, and 525 miRNAs were identified in lychee. A differential expression (DE) analysis revealed that there were 1095 DEmRNAs, 89 DElncRNAs, 28 DEcircRNAs, and 28 DEmiRNAs in the LDB-treated fruits, as well as 1158 DEmRNAs, 132 DElncRNAs, 13 DEcircRNAs, and 197 DEmiRNAs in the LDB-treated leaves. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that the potential function of DEmRNAs and the targets of ncRNAs were involved in plant defense. Furthermore, co-expression networks of putative interacting ncRNAs and mRNAs were developed, in which mRNAs encoded some receptor proteins, pointing to potential ncRNAs associated with LDB infection. Our study provided a new, brief insight to the putative role of ncRNAs in lychee response to LDB. [ABSTRACT FROM AUTHOR]

NAC proteins play an essential role in the growth and development of litchi, especially during reproductive development. However, a comprehensive analysis of the litchi NAC gene family is currently absent. Based on information from the litchi genome, we found that the 112 NAC genes of litchi show an uneven distribution on the chromosomes. Phylogenetic and conserved structural domain analyses indicated that different types of variability were exhibited in the family of litchi NACs (LcNACs). Gene covariance analysis showed that the LcNACs showed better similarity in the same genus than with Arabidopsis. We further investigated the differential expression patterns of LcNACs in buds and rudimentary leaves of litchi. qRT-PCR results implied that they were involved in the process. Profiling of LcNAC promoter elements in litchi showed that they were extensively involved in light response, phytohormone regulation, abiotic stress response, and plant growth and development processes. This study provides new insights into the identification, structural characterization, tissue-specific expression analysis, and promoter response elements of LcNACs. It reveals the characteristics of the LcNACs and lays the foundation for the subsequent understanding of its biological functions and molecular regulatory mechanisms. [ABSTRACT FROM AUTHOR]

Objectives: To explore the underlying mechanism of total flavonoids of Litchi seed (TFLS) in treating prostate cancer (PCa). Methods: Cell Counting Kit-8 (CCK-8), EdU incorporation assay, trypan blue dye assay and colony formation assay were employed to evaluate the effect of TFLS on PCa in vitro. The xenograft mouse model was established to explore the anti-tumour effect of TFLS in vivo. Alterations in the metabolic profiles of the PC3 cells and mouse serum were obtained by untargeted metabolomics. Combination with metabolomics analysis and network pharmacology strategies, the potential targets were predicted and further validated by RT-qPCR. Key findings: TFLS attenuated PCa progression both in vitro and in vivo. Metabolomics results yielded from cells and serum indicated that the anti-cancer effect of TFLS was correlated with synergistic modulation of five common metabolic pathways including glycerophospholipid metabolism, arginine and proline metabolism, glycine, serine and threonine metabolism, tryptophan metabolism and steroid biosynthesis. Using in silico prediction and RT-qPCR analysis, we further revealed that TFLS exerted anti-PCa activities via regulating the expressions of nine genes, including MAOA, ACHE, ALDH2, AMD1, ARG1, PLA2G10, PLA2G1B, FDFT1 and SQLE. Conclusions: TFLS suppressed tumour proliferation in PCa, which may be associated with regulating lipid and amino acid metabolisms. [ABSTRACT FROM AUTHOR]

An unusual infestation of litchi fruit by the non-marine snail, Rhachis bengalensis (Lamarck, 1822) was the first time observed in litchi cultivating orchards in Muzaffarpur during May and June of 2019. In India, infestation and damage to vegetable and fruit crops by Achatina fulica (Bowdich), Pila globose (Swainson), Indosuccinea semiserica (Gould) were previously reported by many scientists. Achatina fulica was previously reported to cause severe damage to papaya, brinjal, beans, okra, rubber buds and guava while P. globosa was reported as a devastating pest of paddy and legume crops. The R. bengalensis was for the first time observed to infest litchi by sucking sap and feeding on the pulp of cracked litchi fruit during long periods of extremely warm weather. Results showed moderate infestation and an average of more than five snails was found per litchi plant. The damage caused by R. bengalensis through sucking sap and feeding pulp that led to abrasions on fruits and caused fungal contamination through their faces and slim wrinkle marks or deep slash mark on the pulp indicates the mode of infestation. In the host choice, the snails preferred cracked ripen litchi fruits more than others. [ABSTRACT FROM AUTHOR]

To investigate the feasibility of developing litchi leaves as silage, we determined the fermentation quality of four varieties of litchi leaves (including "Wanpu", "Wuyejiu", "Tongzai" and "Zhuangyuanhong") ensiled with or without Lactobacillus plantarum on day 3, 7, 14 and 30. The in vitro dry matter digestibility and gas production of litchi leaves silages were also determined after 30 days of ensiling. The results showed that Lactobacillus plantarum significantly reduced pH value (p < 0.01), inhibited coliform bacteria, and reduced the production of ammonia nitrogen (p < 0.01) in all the four kinds of litchi leaves silage. Moreover, Lactobacillus plantarum treated litchi leaves ("Wanpu" and "Zhuangyuanhong") had lower yeasts than the untreated litchi leaves during ensiling. The number of molds in Lactobacillus plantarum treated groups ("Tongzai" and "Zhuangyuanhong") was below the detected level after 30 days ensiling, which was lower than that of the untreated groups. The addition of Lactobacillus plantarum also contributed to improving IVDMD and markedly reduced (p < 0.01) gas production of all litchi leaves silages. Conclusions: Lactobacillus plantarum can improve the fermentation quality and in vitro digestion characteristics of litchi leaves silage. Developing litchi leaves as silage material is a feasible way to recycle litchi leaves. [ABSTRACT FROM AUTHOR]

Litchi (Litchi chinensis Sonn.) fruit deterioration occurs rapidly after harvest and is characterized by pericarp browning, pulp softening, and decay. In this study, we found that calcium chloride (CaCl2) treatment (5 g L−1 CaCl2 solution vacuum infiltration for 5 min) affected the cell wall component contents and cell wall-degrading enzyme activities of litchi fruit during storage at room temperature. CaCl2 treatment significantly increased the contents of Ca2+ and cellulose, while it decreased the water-soluble pectin content, and the activities of polygalacturonase, β-galactosidase, and cellulase in the litchi pericarp. Meanwhile, the treatment resulted in significantly increased contents of Ca2+, water-soluble pectin, ionic-soluble pectin, covalent-soluble pectin and hemicellulose, and upregulated activities of pectinesterase and β-galactosidase, while significantly decreasing the activities of polygalacturonase and cellulase in litchi pulp. The above results indicate that CaCl2 treatment strengthened the cell wall structure of litchi fruit. More importantly, the enzymatic browning of the pericarp, softening of the pulp, and disease incidence were delayed. The treatment had a more pronounced effect on the pericarp than on the pulp. We consider CaCl2 treatment to be a safe and effective treatment for maintaining the postharvest quality of litchi fruit. [ABSTRACT FROM AUTHOR]

In flowering plants, floral induction signals intersect at the shoot apex to modulate meristem determinacy and growth form. Here, we report a single-nucleus RNA sequence analysis of litchi apical buds at different developmental stages. A total of 41 641 nuclei expressing 21 402 genes were analyzed, revealing 35 cell clusters corresponding to 12 broad populations. We identify genes associated with floral transition and propose a model that profiles the key events associated with litchi floral meristem identity by analyzing 567 identified floral meristem cells at single cell resolution. Interestingly, single-nucleus RNA-sequencing data indicated that all putative FT and TFL1 genes were not expressed in bud nuclei, but significant expression was detected in bud samples by RT–PCR. Based on the expression patterns and gene silencing results, we highlight the critical role of LcTFL1-2 in inhibiting flowering and propose that the LcFT1 / LcTFL1-2 expression ratio may determine the success of floral transition. In addition, the transport of LcFT1 and LcTFL1-2 mRNA from the leaf to the shoot apical meristem is proposed based on in situ and dot-blot hybridization results. These findings allow a more comprehensive understanding of the molecular events during the litchi floral transition, as well as the identification of new regulators. [ABSTRACT FROM AUTHOR]

Litchi (Litchi chinensis) is an economically important fruit tree in southern China and is widely cultivated in subtropical regions. However, irregular flowering attributed to inadequate floral induction leads to a seriously fluctuating bearing. Litchi floral initiation is largely determined by cold temperatures, whereas the underlying molecular mechanisms have yet to be identified. In this study, we identified four CRT/DRE BINDING FACTORS (CBF) homologs in litchi, of which LcCBF1, LcCBF2 and LcCBF3 showed a decrease in response to the floral inductive cold. A similar expression pattern was observed for the MOTHER OF FT AND TFL1 homolog (LcMFT) in litchi. Furthermore, both LcCBF2 and LcCBF3 were found to bind to the promoter of LcMFT to activate its expression, as indicated by the analysis of yeast-one-hybrid (Y1H), electrophoretic mobility shift assays (EMSA), and dual luciferase complementation assays. Ectopic overexpression of LcCBF2 and LcCBF3 in Arabidopsis caused delayed flowering and increased freezing and drought tolerance, whereas overexpression of LcMFT in Arabidopsis had no significant effect on flowering time. Taken together, we identified LcCBF2 and LcCBF3 as upstream activators of LcMFT and proposed the contribution of the cold-responsive CBF to the fine-tuning of flowering time. [ABSTRACT FROM AUTHOR]