Comprehensive analysis of transcriptomics and metabolomics provides insights into the mechanism by plant growth regulators affect the quality of jujube (Ziziphus jujuba Mill.) fruit.

A comprehensively analysis of the transcriptomics and metabolomics was conducted to investigate the mechanism of plant growth regulators on the quality of jujube fruit. After the application of plant growth regulators, a total of 3097 differentially expressed genes (DEGs) were identified, which were mainly annotated in 123 pathways such as flavonoid biosynthesis, metabolism of alanine, aspartate, and glutamate. In addition, 1091 differential expressed metabolites (DEMs), including 519 up-regulated and 572 down-regulated metabolites, were significantly altered after application of plant growth regulators. DEGs and DEMs simultaneously annotated 69 metabolic pathways, including biosynthesis of phenylpropane, flavonoid, starch and sucrose. The key genes in flavonoid biosynthesis pathway were revealed, which may play an important role in plant growth regulator regulation quality of jujube fruit. Besides, the application of plant growth regulator during the jujube flowering period increased the contents of gibberellin and indole-3-acetic acid in leaves, and decreased the contents of abscisic acid. The results may help to reveal the metabolic network and molecular mechanism of plant growth regulators in jujube fruit.

Transcriptomic responses of 'Huping jujube' (Zizyphus jujuba mill. cv. Huping) fruit to combined treatment of acidic electrolyzed water and high-voltage electrostatic field.

The molecular mechanism underlying the preserving superior quality attributes of postharvest Huping jujube fruit by combining acidic electrolyzed water and high-voltage electrostatic field (AH) treatment remained unclear. The high-throughput sequencing analysis revealed a total of 3590 common differentially expressed genes (DEGs) in the T-W-CK0 vs T-W-CK75 and T-W-CK75 vs T-W-AH75 groups. AH treatment down-regulated most genes associated with respiratory metabolism, as well as lignin and anthocyanin biosynthesis, thereby maintaining lower physiological activities, improving taste and color quality of mature-white jujube. Additionally, AH treatment downregulated the genes involved in reactive oxygen species (ROS) generation and disease resistance, while simultaneously upregulating the genes associated with ROS elimination. This suggested that AH treatment could inhibit pathogen infection to prevent the activation of plants' active defense and reduce the ROS-induced damage. In sum, the present study provided a comprehension explanation that AH treatment improved the storage quality attributes of jujube fruit at the genetic level.

Combined analysis of transcriptomics with metabolomics provides insights into the resistance mechanism in winter jujube using L-Methionine.

Black rots lead to great economic losses in winter jujube industry. The objective of this research was to delve into the underlying mechanisms of enhanced resistance of winter jujube fruit to black rot by L-Methionine (Met) treatment. The findings revealed that the application of Met significantly curtailed lesion diameter and decay incidence in winter jujube fruit. The peroxidase (POD) activity in the Met-treated jujubes was 3.06-fold that in the control jujubes after 4 d of treatment. By day 8, the activities of phenylalanine ammonia-lyase (PAL), chitinase (CHI) and ß-1,3-glucanase (GLU) in the Met-treated jujubes had surged to their zenith, being 1.39, 1.22, and 1.52 times in the control group, respectively. At the end of storage, the flavonoid and total phenol content remained 1.58 and 1.06 times than that of the control group. Based on metabolomics and transcriptomics analysis, Met treatment upregulated 6 key differentially expressed metabolites (DEMs) (succinic acid, trans-ferulic acid, salicylic acid, delphinium pigments, (S)-abscisic acid, and hesperidin-7-neohesperidin), 12 key differentially expressed genes (DEGs) (PAL, CYP73A, COMT, 4CL, CAD, POD, UGT72E, ANS, CHS, IAA, TCH4 and PR1), which were involved in phenylpropanoid biosynthesis pathway, flavonoid biosynthesis pathway and plant hormone signal transduction pathway. Further analysis revealed that the most of the enzymes, DEMs and DEGs in this study were associated with both antioxidant and disease resistance. Consequently, Met treatment enhanced disease resistance of winter jujube fruit by elevating antioxidant capacity and triggering defense response. This study might provide theoretical support for utilizing Met in the management and prevention of post-harvest black rot in winter jujube.

Systematic exploration of Ziziphus species collection and gene identification influencing physiological traits using genotype-by-sequencing technology.

The Ziziphus genus, belonging to the Rhamnaceae family, holds significant economic, nutritional, and medicinal value. However, much remains to be discovered about its diversity and physical characteristics. Factors such as growth, resilience to changes, disease resistance, and unique features contribute to the quality of Ziziphus species. This study aims to investigate the genomes of 200 genotypes from five Ziziphus species: Ziziphus jujuba (Zj), Ziziphus nummularia (Zm), Ziziphus oxyphylla (Zx), Ziziphus mauritiana (Zm), and the cultivated variety Ziziphus jujube var. jujube, collected from Pakistan and China. Our goal is to identify single nucleotide polymorphisms (SNPs) associated with eight different traits and understand the genetic diversity within the selected Ziziphus species and their genotypes. Using high-quality SNPs obtained through genotype-by-sequencing (GBS), we conducted population structure, phylogenetic, and principal coordinates analyses, identifying a total of 10,945 clean SNPs. These genotypes were categorized into two groups, A and B. Natural Ziziphus variants in Pakistan, specifically Z. jujuba and Z. nummularia, exhibited high levels of genetic diversity and polymorphic information content (PIC) of 0.46 and 0.41, respectively, compared to other species. Furthermore, we identified 15 influential candidate genes that play crucial roles in regulating agronomic traits, such as fruit width and diameter, leaf width, plant height, and stem diameter within this group. This study provides valuable insights that can be utilized in Ziziphus breeding efforts.

Integration analysis of miRNA-mRNA pairs between two contrasting genotypes reveals the molecular mechanism of jujube (Ziziphus jujuba Mill.) response to high-temperature stress.

With global warming, high temperature (HT) has become one of the most common abiotic stresses resulting in significant crop yield losses, especially for jujube (Ziziphus jujuba Mill.), an important temperate economic crop cultivated worldwide. This study aims to explore the coping mechanism of jujube to HT stress at the transcriptional and post-transcriptional levels, including identifying differentially expressed miRNAs and mRNAs as well as elucidating the critical pathways involved. High-throughput sequencing analyses of miRNA and mRNA were performed on jujube leaves, which were collected from "Fucumi" (heat-tolerant) and "Junzao" (heat-sensitive) cultivars subjected to HT stress (42 °C) for 0, 1, 3, 5, and 7 days, respectively. The results showed that 45 known miRNAs, 482 novel miRNAs, and 13,884 differentially expressed mRNAs (DEMs) were identified. Among them, integrated analysis of miRNA target genes prediction and mRNA-seq obtained 1306 differentially expressed miRNAs-mRNAs pairs, including 484, 769, and 865 DEMIs-DEMs pairs discovered in "Fucuimi", "Junzao" and two genotypes comparative groups, respectively. Furthermore, functional enrichment analysis of 1306 DEMs revealed that plant-pathogen interaction, starch and sucrose metabolism, spliceosome, and plant hormone signal transduction were crucial pathways in jujube leaves response to HT stress. The constructed miRNA-mRNA network, composed of 20 DEMIs and 33 DEMs, displayed significant differently expressions between these two genotypes. This study further proved the regulatory role of miRNAs in the response to HT stress in plants and will provide a theoretical foundation for the innovation and cultivation of heat-tolerant varieties.

Integrated anatomical structure, physiological, and transcriptomic analyses to identify differential cold tolerance responses of Ziziphus jujuba mill. 'Yueguang' and its autotetraploid 'Hongguang'.

Cold stress is a limiting stress factor that limits plant distribution and development; however, polyploid plants have specific characteristics such as higher resistance to abiotic stress, especially cold stress, that allow them to overcome this challenge. The cultivated cultivar Ziziphus jujuba Mill. 'Yueguang' (YG) and its autotetraploid counterpart 'Hongguang' (HG) exhibit differential cold tolerance. However, the underlying molecular mechanism and methods to enhance their cold tolerance remain unknown. Anatomical structure and physiological analysis indicated YG had a higher wood bark ratio, and xylem ratio under cold treatment compared to HG. However, the half-lethal temperature (LT50), cortex ratio, and malondialdehyde (MDA) content were significantly decreased in YG than HG, which indicated YG was cold tolerant than HG. Transcriptome analysis showed that 2084, 1725, 2888, and 2934 differentially expressed genes (DEGs) were identified in HC vs YC, H20 vs Y20, Y20 vs YC, and H20 vs HC treatment, respectively. Meanwhile, KEGG enrichment analysis of DEGs showed that several metabolic pathways, primarily plant hormone signal transduction and the MAPK signaling pathway, were involved in the differential regulation of cold tolerance between YG and HG. Furthermore, exogenous abscisic acid (ABA) and brassinolide (BR) treatments could improve their cold tolerance through increased SOD and POD activities, decreased relative electrical conductivity, and MDA content. All of these findings suggested that plant hormone signal transduction, particularly ABA and BR, might have an important role in the regulation of differential cold tolerance between YG and HG, laying the foundation for further improving cold tolerance in jujube and examining the molecular mechanisms underlying differences in cold tolerance among different ploidy cultivars.

Effects of high-temperature stress on gene expression related to photosynthesis in two jujube (Ziziphus jujuba Mill.) varieties.

Elevated temperatures critically impact crop growth, development, and yield, with photosynthesis being the most temperature-sensitive physiological process in plants. This study focused on assessing the photosynthetic response and genetic adaptation of two different heat-resistant jujube varieties 'Junzao' (J) and 'Fucuimi' (F), to high-temperature stress (42°C Day/30°C Night). Comparative analyses of leaf photosynthetic indices, microstructural changes, and transcriptome sequencing were conducted. Results indicated superior high-temperature adaptability in F, evidenced by alterations in leaf stomatal behavior - particularly in J, where defense cells exhibited significant water loss, shrinkage, and reduced stomatal opening, alongside a marked increase in stomatal density. Through transcriptome sequencing 13,884 differentially expressed genes (DEGs) were identified, significantly enriched in pathways related to plant-pathogen interactions, amino acid biosynthesis, starch and sucrose metabolism, and carbohydrate metabolism. Key findings include the identification of photosynthetic pathway related DEGs and HSFA1s as central regulators of thermal morphogenesis and heat stress response. Revealing their upregulation in F and downregulation in J. The results indicate that these genes play a crucial role in improving heat tolerance in F. This study unveils critical photosynthetic genes involved in heat stress, providing a theoretical foundation for comprehending the molecular mechanisms underlying jujube heat tolerance.

Budding mutation reprogrammed flavonoid biosynthesis in jujube by deploying MYB41 and bHLH93.

Budding mutations are known to cause metabolic changes in new jujube varieties; however, the mechanisms underlying these changes are still unclear. Here, we performed muti-omics analysis to decipher the detailed metabolic landscape of "Saimisu 1" (S1) and its budding mutation line "Saimisu 2" (S2) at all fruit stages. We found that the genes involved in the biosyntheses of flavonoids, phenylpropanoids, and amino acids were upregulated in S2 fruits at all stages, especially PAL and DFR, resulting in increased accumulation of related compounds in S2 mature fruits. Further co-expression regulatory network analysis showed that the transcription factors MYB41 and bHLH93 potentially regulated the expression of PAL and DFR, respectively, by directly binding to their promoters. Moreover, the overexpression of MYB41 or bHLH93 induced their expression levels to redirect the flux of the flavonoid biosynthetic pathway, eventually leading to high levels of related compounds in S2 fruits. Overall, this study revealed the metabolic variations between S1 and S2 and contributed to the understanding of the mechanisms underlying budding mutation-mediated metabolic variations in plants, eventually providing the basis for breeding excellent jujube varieties using budding mutation lines.

Characteristics of ZjCIPKs and ZjbHLH74-ZjCIPK5 regulated cold tolerance in jujube.

CIPKs are kind of serine/threonine (Ser/Thr) protein kinases which play important roles in response to biotic and abiotic stresses, and in plant growth and development. However, CIPKs in jujube (Ziziphus jujuba Mill.) had limited information, especially regarding their response to cold stress. In the current study, a total of 18 ZjCIPKs were identified in jujube genome which unevenly distributed on seven chromosomes. Conserved motif and gene structural analysis depicted them with conserved DEGLSA and APE motifs and similar structures. Phylogenetic analysis indicated that CIPKs were classified into five subgroups (I-V). In addition, three pairs of ZjCIPKs exhibited tandem duplication while the segmental duplication of ZjCIPKs was not identified. Study on the cis-acting elements indicted that stress or hormone related cis-acting elements were distributed unevenly on ZjCIPKs promoters and most ZjCIPKs were down- or up-regulated by the cold stress. VIGS induced silencing of ZjCIPK5 decreased the cold tolerance of sour jujube. Subcellular location analysis showed ZjCIPK5 located in nucleus. Moreover, transcription factor ZjbHLH74 which was induced at 6 h under cold stress could interact with the promoter of ZjCIPK5 to regulate jujube cold tolerance. These findings provided insights to a molecular basis of CIPK5 in jujube cold tolerance breeding for future.

The 'Candidatus Phytoplasma ziziphi' effectors SJP1/2 negatively control leaf size by stabilizing the transcription factor ZjTCP2 in jujube.

Phytoplasmas manipulate host plant development to benefit insect vector colonization and their own invasion. However, the virulence factors and mechanisms underlying small-leaf formation caused by jujube witches' broom (JWB) phytoplasmas remain largely unknown. Here, effectors SJP1 and SJP2 from JWB phytoplasmas were identified to induce small-leaf formation in jujube (Ziziphus jujuba). In vivo interaction and expression assays showed that SJP1 and SJP2 interacted with and stabilized the transcription factor ZjTCP2. Overexpression of SJP1 and SJP2 in jujube induced ZjTCP2 accumulation. In addition, the abundance of miRNA319f_1 was significantly reduced in leaves of SJP1 and SJP2 transgenic jujube plants and showed the opposite pattern to the expression of its target, ZjTCP2, which was consistent with the pattern in diseased leaves. Overexpression of ZjTCP2 in Arabidopsis promoted ectopic leaves arising from the adaxial side of cotyledons and reduced leaf size. Constitutive expression of the miRNA319f_1 precursor in the 35S::ZjTCP2 background reduced the abundance of ZjTCP2 mRNA and reversed the cotyledon and leaf defects in Arabidopsis. Therefore, these observations suggest that effectors SJP1 and SJP2 induced small-leaf formation, at least partly, by interacting with and activating ZjTCP2 expression both at the transcriptional and the protein level, providing new insights into small-leaf formation caused by phytoplasmas in woody plants.

DNA barcoding identification of grafted Semen Ziziphi Spinosae and transcriptome study of wild Semen Ziziphi Spinosae.

Semen Ziziphi Spinosae (SZS) is the dried and ripe seeds of Ziziphus jujuba var. spinosa. Currently, the yield of naturally grown SZS is unstable owing to environmental factors. Grafting high-quality sour jujube scions onto sour jujube or jujube tree stocks can result in a greater yield. However, the effects of grafting on the quality and gene expression of SZS have rarely been reported. This study used a DNA barcoding technique, high-performance liquid phase-evaporative luminescence detector (HPLC-ELSD), and transcriptomics to investigate the origin and genetic differences between grafted and wild jujube seeds. DNA barcoding identified all samples as Ziziphus jujuba var. spinosa. HPLC-ELSD analysis revealed a higher content of grafted SZS compared to that of the wild SZS. Transcriptome analysis of the metabolic pathways in SZS showed that 22 and 19 differentially expressed gene sequences encoded enzymes related to flavonoids and saponin synthesis, respectively. Weighted correlation network analysis (WGCNA) identified 15 core genes governing the differences in medicinal components between grafted and wild SZS. This study demonstrated the use of DNA barcoding and fingerprint methods to identify jujube seed species and effectively capture ingredient information of medicinal materials. Additionally, transcriptome technology provided data for identifying core differential genes, facilitating studies on quality differences between grafted and wild SZS.

Morphological characterization and interspecific variation among five species of Ziziphus genus to select superiors in Iran.

BACKGROUND: Several species of the genus Ziziphus are used worldwide for their medicinal and therapeutic properties. The present study aimed to investigate the phenotypic variation of five species of the Ziziphus genus, including Z. jujuba Mill. (25 accessions), Z. mauritiana Lam. (25 accessions), Z. spina-christi L. (25 accessions), Z. nummularia L. (10 accessions), and Z. xylopyrus Willd. (10 accessions) from Markazi, Sistan-va-Baluchestan, and Khuzestan provinces, Iran. RESULTS: The investigated accessions have significant differences in terms of all the measured as revealed using analysis of variance (ANOVA, P < 0.01). The range of fruit weight was 0.43-1.29 g in Z. jujuba, 17.85-29.87 g in Z. mauritiana, 0.94-3.44 g in Z. spina-christi, 0.93-2.02 g in Z. nummularia, and 0.91-3.02 g in Z. xylopyrus. All the measured traits showed significant and positive correlations with each other. Multiple regression analysis (MRA) results showed that fruit length, stone width, stone weight, stone length, and fruit width have significant effects on fruit weight, and thus their fluctuations have a significant effect on increasing or decreasing fruit weight. The accessions were grouped into two main clusters using hierarchical cluster analysis. The first cluster (I) included all the accessions of Z. mauritiana, while the second cluster (II) contained the accessions of the rest species forming two sub-clusters. CONCLUSION: Based on the commercial characters, accessions no. 12, 13, 17, 23, and 24 in Z. jujuba, accessions no. 3, 9, 17, 18, 20, 22, and 23 in Z. mauritiana, accessions no. 5, 6, 8, 13, 19, 22, and 24 in Z. spina-christi, accessions no. 3, 7, and 9 in Z. nummularia, and accessions no. 2, 4, 7, and 10 in Z. oxyphylla showed the highest fruit weight and thus can be suggested as superior for cultivation or use in breeding programs due to having larger fruits.

Genome-wide analysis of ALDH gene family in jujube and identification of ZjALDH3F3 for its important role in high-temperature tolerance.

Aldehyde dehydrogenases (ALDHs) are NAD(P)-dependent enzymes that oxidize aliphatic and aromatic aldehydes. They play crucial roles in various biological processes and plant responses to stress. The impact of high temperatures on jujube quality and yield has been well documented. Nevertheless, the involvement of ALDHs in the response to heat stress remains poorly understood. This study aimed to identify ZjALDHs in the jujube genome (Ziziphus jujuba var. spinosa) and conducted in silico analyses. Phylogenetic analyses indicated that ALDHs in plants, including jujube, can be divided into ten families, and members from the same family share conserved gene and protein structures. Quantitative real-time PCR (qRT-PCR) and ß-glucuronidase (GUS) histochemical staining were used to analyze the expression patterns of ZjALDHs in response to elevated temperatures. We identified a ZjALDH (ZjALDH3F3) gene displaying a significant upregulation and down-regulation, respectively in heat-resistant (HR) and heat-sensitive (HS) jujube in response to heat treatments. Such specific responses are probably attributed to the different heat-responsive cis-elements of ZjALDH3F3 in HR and HS jujubes. ZjALDH3F3 over-expressed in tobacco increased heat tolerance, as evidenced by the reduced accumulation of reactive oxygen species (ROS) and elevated activity of antioxidant enzymes. The qRT-PCR results indicated that the expression of antioxidant enzymes, abscisic acid (ABA), and stress-responsive genes was enhanced in transgenic tobacco. This study sheds novel light on the function of ZjALDHs in heat resistance of jujube.

ZjWRKY23 and ZjWRKY40 Promote Fruit Size Enlargement by Targeting and Downregulating Cytokinin Oxidase/Dehydrogenase 5 Expression in Chinese Jujube.

Fruit size is crucial for fruit trees, as it contributes to both quality and yield. However, the underlying mechanism of fruit size regulation remains largely unknown. Taking advantage of using a fruit double-sized bud mutant of Chinese jujube, "Jinkuiwang" and its wild type, "Jinsixiaozao", we carried out a comprehensive study on the mechanism of fruit size development in jujube. Using weighted gene coexpression network analyses, a number of candidate regulators for fruit size including those involved in hormonal signaling pathways, transcription factors, and heat shock proteins were identified. A hub gene named cytokinin oxidase/dehydrogenase 5 (ZjCKX5), responsible for cytokinin degradation, was found to play a negative role in regulating fruit size development, and overexpressing ZjCKX5 in tomato and Arabidopsis resulted in much smaller fruits and dwarf plants. Furthermore, another two hub genes, ZjWRKY23 and ZjWRKY40 transcription factors, were found to participate in fruit size regulation by targeting and downregulating the ZjCKX5 expression. Overexpressing ZjWRKY23 or ZjWRKY40 in tomato led to much larger fruits and promoted plant architecture. Based on these results, a molecular framework for jujube fruit size regulation, namely, ZjWRKY-ZjCKX5 module, was proposed. This study provides a new insight into the molecular networks underlying fruit size regulation.

Biological Characteristics and Functional Analysis of the Linoleic Acid Synthase Gene ZjFAD2 in Jujube.

Jujube fruit is rich in linoleic acid and other bioactive components and has great potential to be used for the development of functional foods. However, the roles of FAD2 genes in linoleic acid biosynthesis in jujube fruit remain unclear. Here, we identified 15 major components in jujube and found that linoleic acid was the main unsaturated fatty acid; major differences in the content and distribution of linoleic acid in the pulp and seeds were observed, and levels of linoleic acid decreased during fruit maturation. Analysis of the fatty acid metabolome, genome, and gene expression patterns of cultivated and wild-type jujube revealed five ZjFAD2 family members highly related to linoleic acid biosynthesis. The heterologous expression of these five ZjFAD2 family members in tobacco revealed that all five of these genes increased the content of linoleic acid. Additionally, transient expression of these genes in jujube fruit and the virus-induced gene silencing (VIGS) test further confirmed the key roles of ZjFAD2-11 and ZjFAD2-1 in the biosynthesis of linoleic acid. The results of this research provide valuable insights into the molecular mechanism underlying linoleic acid synthesis in jujube and will aid the development of quality-oriented breeding strategies.

Anatomical observation and transcriptome analysis of branch-twisted mutations in Chinese jujube.

BACKGROUND: Plant organs grow in a certain direction and organ twisted growth, a rare and distinctive trait, is associated with internal structure changes and special genes. The twisted branch mutant of Chinese jujube jujube, an important fruit tree native to China and introduced to nearly 50 countries, provides new typical materials for exploration of plant twisted growth. RESULTS: In this study, the cytological characteristics and related genes of twisted branches in Chinese jujube were revealed by microscopy observation and transcriptome analysis. The unique coexistence of primary and secondary structures appeared in the twisted parts of branches, and special structures such as collateral bundle, cortical bundles, and internal phloem were formed. Ninety differentially expressed genes of 'Dongzao' and its twisted mutant were observed, in which ZjTBL43, ZjFLA11, ZjFLA12 and ZjIQD1 were selected as candidate genes. ZjTBL43 was homologous to AtTBL43 in Arabidopsis, which was involved in the synthesis and deposition of cellular secondary wall cellulose. The attbl43 mutant showed significant inflorescence stem bending growth. The transgenic lines of attbl43 with overexpression of ZjTBL43 were phenotypically normal.The branch twisted growth may be caused by mutations in ZjTBL43 in Chinese jujube. AtIQD10, AtFLA11 and AtFLA12 were homologous to ZjIQD1, ZjFLA11 and ZjFLA12, respectively. However, the phenotype of their function defect mutants was normal. CONCLUSION: In summary, these findings will provide new insights into the plant organ twisted growth and a reference for investigation of controlling mechanisms of plant growth direction.

Analysis of the Glycoside Hydrolase Family 1 from Wild Jujube Reveals Genes Involved in the Degradation of Jujuboside A.

Jujubosides are the major medicinal ingredients of Ziziphi Spinosae Semen (the seed of wild jujube). To date, a complete understanding of jujuboside's metabolic pathways has not been attained. This study has systematically identified 35 ß-glucosidase genes belonging to the glycoside hydrolase family 1 (GH1) using bioinformatic methods based on the wild jujube genome. The conserved domains and motifs of the 35 putative ß-glucosidases, along with the genome locations and exon-intron structures of 35 ß-glucosidase genes were revealed. The potential functions of the putative proteins encoded by the 35 ß-glucosidase genes are suggested based on their phylogenetic relationships with Arabidopsis homologs. Two wild jujube ß-glucosidase genes were heterologously expressed in Escherichia coli, and the recombinant proteins were able to convert jujuboside A (JuA) into jujuboside B (JuB). Since it has been previously reported that JuA catabolites, including JuB and other rare jujubosides, may play crucial roles in the jujuboside's pharmacological activity, it is suggested that these two proteins can be used to enhance the utilization potential of jujubosides. This study provides new insight into the metabolism of jujubosides in wild jujube. Furthermore, the characterization of ß-glucosidase genes is expected to facilitate investigations involving the cultivation and breeding of wild jujube.

Influences of Jujube Witches' Broom (JWB) Phytoplasma Infection and Oxytetracycline Hydrochloride Treatment on the Gene Expression Profiling in Jujube.

Jujube witches' broom disease (JWB), caused by Candidatus Phytoplasma ziziphi, is the most destructive phytoplasma disease threatening the jujube industry. Tetracycline derivatives treatments have been validated to be capable of recovering jujube trees from phytoplasma infection. In this study, we reported that oxytetracycline hydrochloride (OTC-HCl) trunk injection treatment could recover more than 86% of mild JWB-diseased trees. In order to explore the underlying molecular mechanism, comparative transcriptomic analysis of healthy control (C group), JWB-diseased (D group) and OTC-HCl treated JWB-diseased (T group) jujube leaves was performed. In total, 755 differentially expressed genes (DEGs), including 488 in 'C vs. D', 345 in 'D vs. T' and 94 in 'C vs. T', were identified. Gene enrichment analysis revealed that these DEGs were mainly involved in DNA and RNA metabolisms, signaling, photosynthesis, plant hormone metabolism and transduction, primary and secondary metabolisms, their transportations, etc. Notably, most of the DEGs identified in 'C vs. D' displayed adverse change patterns in 'D vs. T', suggesting that the expression of these genes was restored after OTC-HCl treatment. Our study revealed the influences of JWB phytoplasma infection and OTC-HCl treatment on gene expression profiling in jujube and would be helpful for understanding the chemotherapy effects of OTC-HCl on JWB-diseased jujube.