Explore the vast range of titles available.

Background Litchi, an important tropical fruit, is severely affected by anthracnose disease. However, the mechanism of its disease resistance response remains unknown, and resistant accession genetic resources and resistance-related genes have not yet been identified. Results In this study, 82 accessions of litchi were evaluated for resistance to Colletotrichum gloeosporioides , and the accessions ‘Haiken 5’ and ‘Nongmei 5 hao’ were identified as resistant and susceptible, respectively. Leaves from these two accessions were inoculated with C . gloeosporioides and collected at 6 and 24 h for use as materials for transcriptome analysis. Analyses of the differentially expressed genes (DEGs) between the accessions and their controls, which were inoculated with potato dextrose agar medium, revealed that the resistant accession presented more DEGs with smaller changes in magnitude, whereas the susceptible accession presented fewer DEGs with greater changes in magnitude. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed, and phenylpropanoid biosynthesis, amino sugar and nucleotide sugar metabolism, and plant–pathogen interactions were identified as common pathways. Chitinase activity, oxidoreductase activity, aminoglycan and glucosamine-containing compounds, and cell wall metabolic processes also participated in the defence reaction. Salicylic acid signalling in litchi leaves contributed to resistance to C . gloeosporioides . Short Time-series Expression Miner (STEM) and weighted correlation network analysis (WGCNA) were also employed to evaluate the gene expression trends and identify highly correlated genes. Conclusion Litchi accessions presented different resistance responses to anthracnose disease. Small changes in the expression levels of critical resistance-related genes were sufficient to produce the defence reaction. Calcium ion regulatory mechanisms and transcription factors have been preliminarily identified as contributors to disease resistance. Multiple pathways and molecular processes participate in the defence response. These results identify candidate genes and pathways involved in litchi plant defence against anthracnose.

KEY MESSAGE : A novel LcGST4 was identified and characterized from Litchi chinensis . Expression and functional analysis demonstrated that it might function in anthocyanin accumulation in litchi. Glutathione S-transferases (GSTs) have been defined as detoxification enzymes for their ability to recognize reactive electrophilic xenobiotic molecules as well as endogenous secondary metabolites. Anthocyanins are among the few endogenous substrates of GSTs for vacuolar accumulation. The gene encoding a GST protein that is involved in anthocyanin sequestration from Litchi chinensis Sonn. has not been reported. Here, LcGST4, an anthocyanin-related GST, was identified and characterized. Phylogenetic analysis showed that LcGST4 was clustered with other known anthocyanin-related GSTs in the same clade. Expression analysis revealed that the expression pattern of LcGST4 was strongly correlated with anthocyanin accumulation in litchi. ABA- and light-responsive elements were found in the LcGST4 promoter, which is in agreement with the result that the expression of LcGST4 was induced by both ABA and debagging treatment. A GST activity assay in vitro verified that the LcGST4 protein shared universal activity with the GST family. Functional complementation of an Arabidopsis mutant tt19 demonstrated that LcGST4 might function in anthocyanin accumulation in litchi. Dual luciferase assay revealed that the expression of LcGST4 was activated by LcMYB1, a key R2R3-MYB transcription factor that regulates anthocyanin biosynthesis in litchi.

Lychee is an exotic tropical fruit with a distinct flavor. The genome of cultivar ‘Feizixiao’ was assembled into 15 pseudochromosomes, totaling ~470 Mb. High heterozygosity (2.27%) resulted in two complete haplotypic assemblies. A total of 13,517 allelic genes (42.4%) were differentially expressed in diverse tissues. Analyses of 72 resequenced lychee accessions revealed two independent domestication events. The extremely early maturing cultivars preferentially aligned to one haplotype were domesticated from a wild population in Yunnan, whereas the late-maturing cultivars that mapped mostly to the second haplotype were domesticated independently from a wild population in Hainan. Early maturing cultivars were probably developed in Guangdong via hybridization between extremely early maturing cultivar and late-maturing cultivar individuals. Variable deletions of a 3.7 kb region encompassed by a pair of CONSTANS -like genes probably regulate fruit maturation differences among lychee cultivars. These genomic resources provide insights into the natural history of lychee domestication and will accelerate the improvement of lychee and related crops. Two divergent haplotypes from a highly heterozygous lychee genome of the cultivar ‘Feizixiao’ and resequencing of 72 lychee accessions provide insights into the genome evolution and domestication history of lychee.

In contrast to the detailed molecular knowledge available on anthocyanin synthesis, little is known about its catabolism in plants. Litchi (Litchi chinensis) fruit lose their attractive red color soon after harvest. The mechanism leading to quick degradation of anthocyanins in the pericarp is not well understood. An anthocyanin degradation enzyme (ADE) was purified to homogeneity by sequential column chromatography, using partially purified anthocyanins from litchi pericarp as a substrate. The purified ADE, of 116 kD by urea SDS-PAGE, was identified as a laccase (ADE/LAC). The full-length complementary DNA encoding ADE/LAC was obtained, and a polyclonal antibody raised against a deduced peptide of the gene recognized the ADE protein. The anthocyanin degradation function of the gene was confirmed by its transient expression in tobacco (Nicotiana benthamiana) leaves. The highestADE/LACtranscript abundance was in the pericarp in comparison with other tissues, and was about 1,000-fold higher than the polyphenol oxidase gene in the pericarp. Epicatechin was found to be the favorable substrate for the ADE/LAC. The dependence of anthocyanin degradation by the enzyme on the presence of epicatechin suggests an ADE/LAC epicatechin-coupled oxidation model. This model was supported by a dramatic decrease in epicatechin content in the pericarp parallel to anthocyanin degradation. Immunogold labeling transmission electron microscopy suggested that ADE/LAC is located mainly in the vacuole, with essential phenolic substances. ADE/LAC vacuolar localization, high expression levels in the pericarp, and high epicatech-independent anthocyanin degradation support its central role in pigment breakdown during pericarp browning.

Bio-transformations refer to the chemical modifications made by an organism on a chemical compound that often involves the interaction of plants with microbes to alter the chemical composition of soil or plant. Integrating bio-transformations and entomopathogenic fungi into litchi cultivation can enhance symbiotic relationships, microbial enzymatic activity in rhizosphere, disease suppression and promote overall plant health. The integration of biological formulations and entomopathogenic fungi can significantly influence growth, nutrient dynamics, physiology, and rhizosphere microbiome of air-layered litchi ( Litchi chinensis Sonn.) saplings. Biological modifications included, K-mobilizers, AM fungi, Pseudomonas florescence and Azotobacter chroococcum along with Metarhizium , entomopathogenic fungi have been used. The treatments included, T 1 -Litchi orchard soil + sand (1:1); T 2 -Sand + AM fungi +  Azotobacter chroococcum (1:2:1); T 3 -Sand +  Pseudomonas florecence  + K-mobilizer (1:1:1); T 4 - AM fungi + K-mobilizers (1:1); T 5 , P. Florecence  +  A. chroococcum  + K-mobilizer (1:1:1); T 6 -Sand +  P. florecence (1:2) and T 7 -Uninoculated control for field performance. Treatments T 4 -T 6 were further uniformly amended with drenching of Metarrhizium in rhizosphere. T 2 application significantly increased resident microbe survival, total chlorophyll content and root soil ratio in seedlings. A. chroococcum , Pseudomonas , K-mobilizers and AM fungi increased in microbial biomass of 2.59, 3.39, 2.42 and 2.77 times, respectively. Acidic phosphatases, dehydrogenases and alkaline phosphatases were increased in rhizosphere. Leaf nutrients reflected through DOP were considerably altered by T 2 treatment. Based on Eigen value, PCA-induced changes at biological modifications showed maximum total variance. The study inferred that the bio-transformations through microbial inoculants and entomopathogenic fungi could be an encouraging strategy to enhance the growth of plants, health and productivity. Such practices align well with the goals of sustainable agriculture through biological means by reducing dependency on chemical inputs. By delving into these aspects, the research gaps including microbial processes, competitive and symbiotic relationships, resistance in microbes and how complex interactions among bio-transformations, entomopathogenic fungi and microbes can significantly impact the health and productivity of litchi. Understanding and harnessing these interactions can lead to more effective and sustainable farming practices.

Background Litchi, an economically important fruit crop in Southeast Asia, is renowned for its distinctive flavor and nutrient value, but its genetic diversity and genetic basis underlying fruit quality regulation remain largely unexplored. Results We re-sequence 276 litchi accessions collected globally and identify 54 million high-quality biallelic SNPs. We then analyze the population structure and reveal four main subgroups within the population. By phenotypic profiling of 21 fruit-quality-related traits, followed with genome-wide association study, we identify a plethora of candidate genes and genomic loci that are responsible for regulating seed and fruit quality traits. In particular, we characterize and experimentally validate an invertase gene, LcSAI , encoding an enzyme catalyzing the conversion of sucrose into reducing sugars, as a key regulator of sugar composition in litchi fruit, affecting the sweetness of litchi fruits. Conclusions Our study demonstrates the genetic diversity and population structure of litchi. We delineate the genetic basis of fruit quality through comprehensive genomic analyses and phenotypic profiling. These findings provide valuable resources and knowledge for understanding the genetic basis of fruit quality in litchi, which contribute to the theoretical basis for further genetic improvement.

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.

Grafting is a prevalent horticultural technique that enhances crop yields and stress resilience; nevertheless, compatibility issues frequently constrain its efficacy. This research examined the physiological, hormonal, and transcriptional factors regulating compatibility between the litchi (Litchi chinensis Sonn.) cultivars Feizixiao (FZX) and Ziniangxi (ZNX). The anatomical and growth investigations demonstrated significant disparities between compatible (FZX as scion and ZNX as rootstock) and incompatible (ZNX as scion and FZX as rootstock) grafts, with the latter showing reduced levels of indole acetic acid (IAA). Exogenous 1-naphthalene acetic acid (NAA) application markedly improved the graft survival, shoot development, and hormonal synergy, whereas the auxin inhibitor tri-iodobenzoic acid (TIBA) diminished these parameters. The incompatible grafts showed downregulation of auxin transporter genes, including ATP-binding cassette (ABC) transporter, AUXIN1/LIKE AUX1 (AUX/LAX), and PIN-FORMED (PIN) genes, suggesting impaired vascular tissue growth. Metabolomic profiling revealed dynamic interactions between auxin, salicylic acid, and jasmonic acid, with NAA-treated grafts exhibiting enhanced levels of stress-responsive metabolites. Transcriptome sequencing identified differentially expressed genes (DEGs) linked to auxin signaling (ARF, GH3), seven additional phytohormones, secondary metabolism (terpenoids, anthocyanins, and phenylpropanoids), and ABC transporters. Gene ontology and KEGG analyses highlighted the significance of hormone interactions and the biosynthesis of secondary metabolites in successful grafting. qRT-PCR validation substantiated the veracity of the transcriptome data, emphasizing the significance of auxin transport and signaling in effective graft development. This study provides an in-depth review of the molecular and physiological factors influencing litchi grafting. These findings provide critical insights for enhancing graft success rates in agricultural operations via targeted hormonal and genetic approaches.

Climate variability has increasingly disrupted the natural vegetative dormancy of litchi ( Litchi chinensis ), negatively impacting flowering, fruit set, and quality. This study evaluates the combined effect of paclobutrazol (PBZ) and micronutrients (Zinc Sulphate and Boric Acid) on the physical and biochemical quality of litchi fruits in a subtropical agro-climatic region. A factorial randomized block design was employed on 20-year-old litchi trees (cv. Dehradun) with 27 treatment combinations. Results revealed that PBZ @ 50 ppm followed by ZnSO 4 @ 1.0% significantly improved fruit length, weight, pulp percentage, and juice content. The same treatment also enhanced reducing sugars, total soluble solids (TSS), and ascorbic acid content, while optimizing the TSS: acid ratio. Zinc’s role as a cofactor in carbohydrate metabolism and antioxidant enzyme activity, along with PBZ’s vegetative growth suppression, synergistically improved nutrient allocation and fruit quality. Use of 50 ppm PBZ in month of October with 1% zinc sulphate at time of panicle emergence is an integrated approach for mitigating climate-related disruptions and improving litchi productivity and nutritional value.

Background Litchi ( Litchi chinensis Sonn.) is an economically important evergreen fruit tree widely cultivated in subtropical areas. Low temperature is absolutely required for floral induction of litchi, but its molecular mechanism is not fully understood. Leaves of litchi played a key role during floral induction and could be the site of low temperature perception. Therefore, leaves were treated under different temperature (15 °C/25 °C), and high-throughput RNA sequencing (RNA-Seq) performed with leaf samples for the de novo assembly and digital gene expression (DGE) profiling analyses to investigate low temperature-induced gene expression changes. Results 83,107 RNA-Seq unigenes were de novo assembled with a mean length of 1221 bp and approximately 61% of these unigenes (50,345) were annotated against public protein databases. Differentially-expressed genes (DEGs) under low temperature treatment in comparison with the control group were the main focus of our study. Hierarchical clustering analysis arranged 2755 DEGs into eight groups with three significant expression clusters ( p -value ≤ 0.05) during floral induction. With the increasing contents of sugars and starch, the expression of genes involved in metabolism of sugars increased dramatically after low temperature induction. One FT gene ( Unigene0025396 , LcFT1 ) which produces a protein called ‘florigen’ was also detected among DEGs of litchi. LcFT1 exhibited an apparent specific tissue and its expression was highly increased after low temperature induction, GUS staining results also showed GUS activity driven by LcFT1 gene promoter can be induced by low temperature, which indicated LcFT1 probably played a pivotal role in the floral induction of litchi under low temperature. Conclusions Our study provides a global survey of transcriptomes to better understand the molecular mechanisms underlying changes of leaves in response to low temperature induction in litchi. The analyses of transcriptome profiles and physiological indicators will help us study the complicated metabolism of floral induction in the subtropic evergreen plants.