Generation of transgene-free canker-resistant Citrus sinensis cv. Hamlin in the T0 generation through Cas12a/CBE co-editing.

Citrus canker disease affects citrus production. This disease is caused by Xanthomonas citri subsp. citri (Xcc). Previous studies confirmed that during Xcc infection, PthA4, a transcriptional activator like effector (TALE), is translocated from the pathogen to host plant cells. PthA4 binds to the effector binding elements (EBEs) in the promoter region of canker susceptibility gene LOB1 (EBEPthA4-LOBP) to activate its expression and subsequently cause canker symptoms. Previously, the Cas12a/CBE co-editing method was employed to disrupt EBEPthA4-LOBP of pummelo, which is highly homozygous. However, most commercial citrus cultivars are heterozygous hybrids and more difficult to generate homozygous/biallelic mutants. Here, we employed Cas12a/CBE co-editing method to edit EBEPthA4-LOBP of Hamlin (Citrus sinensis), a commercial heterozygous hybrid citrus cultivar grown worldwide. Binary vector GFP-p1380N-ttLbCas12a:LOBP1-mPBE:ALS2:ALS1 was constructed and shown to be functional via Xcc-facilitated agroinfiltration in Hamlin leaves. This construct allows the selection of transgene-free regenerants via GFP, edits ALS to generate chlorsulfuron-resistant regenerants as a selection marker for genome editing resulting from transient expression of the T-DNA via nCas9-mPBE:ALS2:ALS1, and edits gene(s) of interest (i.e., EBEPthA4-LOBP in this study) through ttLbCas12a, thus creating transgene-free citrus. Totally, 77 plantlets were produced. Among them, 8 plantlets were transgenic plants (#HamGFP1 - #HamGFP8), 4 plantlets were transgene-free (#HamNoGFP1 - #HamNoGFP4), and the rest were wild type. Among 4 transgene-free plantlets, three lines (#HamNoGFP1, #HamNoGFP2 and #HamNoGFP3) contained biallelic mutations in EBEpthA4, and one line (#HamNoGFP4) had homozygous mutations in EBEpthA4. We achieved 5.2% transgene-free homozygous/biallelic mutation efficiency for EBEPthA4-LOBP in C. sinensis cv. Hamlin, compared to 1.9% mutation efficiency for pummelo in a previous study. Importantly, the four transgene-free plantlets and 3 transgenic plantlets that survived were resistant against citrus canker. Taken together, Cas12a/CBE co-editing method has been successfully used to generate transgene-free canker-resistant C. sinensis cv. Hamlin in the T0 generation via biallelic/homozygous editing of EBEpthA4 of the canker susceptibility gene LOB1.

Transgene-free genome editing of vegetatively propagated and perennial plant species in the T0 generation via a co-editing strategy.

Transgene-free plant genome editing in the T0 generation is highly desirable but challenging1,2. Here we achieved such a goal using a co-editing strategy via Agrobacterium-mediated transient expression of cytosine base editor to edit ALS encoding acetolactate synthase to confer herbicide chlorsulfuron resistance as a selection marker, Cas12a/CRISPR RNA for editing gene(s) of interest, and green fluorescent protein for selecting transgene-free transformants. The biallelic/homozygous transgene-free mutation rates for target genes among herbicide-resistant transformants ranged from 1.9% to 42.1% in tomato, tobacco, potato and citrus. This co-editing strategy is particularly useful for transgene-free genome editing of vegetatively propagated and perennial plant species in the T0 generation.

Generation of the transgene-free canker-resistant Citrus sinensis using Cas12a/crRNA ribonucleoprotein in the T0 generation.

Citrus canker caused by Xanthomonas citri subsp. citri (Xcc) is a destructive citrus disease worldwide. Generating disease-resistant cultivars is the most effective, environmentally friendly and economic approach for disease control. However, citrus traditional breeding is lengthy and laborious. Here, we develop transgene-free canker-resistant Citrus sinensis lines in the T0 generation within 10 months through transformation of embryogenic protoplasts with Cas12a/crRNA ribonucleoprotein to edit the canker susceptibility gene CsLOB1. Among the 39 regenerated lines, 38 are biallelic/homozygous mutants, demonstrating a 97.4% biallelic/homozygous mutation rate. No off-target mutations are detected in the edited lines. Canker resistance of the cslob1-edited lines results from both abolishing canker symptoms and inhibiting Xcc growth. The transgene-free canker-resistant C. sinensis lines have received regulatory approval by USDA APHIS and are exempted from EPA regulation. This study provides a sustainable and efficient citrus canker control solution and presents an efficient transgene-free genome-editing strategy for citrus and other crops.

Mechanism of Key Ingredient of Astragalus membranaceus on Lung Adenocarcinoma via PI3K/AKT Signaling Clarified by Utilizing Network Pharmacology Approach and Experimental Validation.

OBJECTIVE: To investigate the mechanism of the effect of Astragalus membranaceus (A. membranaceus) on lung adenocarcinoma at the molecular level to elucidate the specific targets according to the network pharmacology approach. METHODS: The active components of A. membranaceus and their potential targets were collected from the Traditional Chinese Medicine Systems Pharmacology Database. Lung adenocarcinoma-associated genes were acquired based on GeneCards, Online Mendelian Inheritance in Man (OMIM), PharmGKB, and Therapeutic Targets databases. The PI3K/AKT signaling pathway-related genes were obtained using Reactome portal. Networks of "ingredient-target" and "ingredient-target-pathway-disease" were constructed using the Cytoscape3.6.0 software. The relationships among targets were analyzed according protein-protein interaction (PPI) network. Finally, molecular docking was applied to construct the binding conformation between active ingredients and core targets. Cell counting kit 8 (CCK8) and Western blot assays were performed to determine the mechanism of the key ingredient of A. membranaceus. RESULTS: A total of 20 active components and their 329 targets, and 7,501 lung adenocarcinoma-related genes and 130 PI3K/AKT signaling pathway-related genes were obtained. According to Venn diagram and PPI network analysis, 2 mainly active ingredients, including kaempferol and quercetin, and 6 core targets, including TP53, MAPK1, EGF, AKT1, ERBB2, and EGFR, were identified. The two important active ingredients of A. membranaceus, kaempferol and quercetin, exert the therapeutic effect in lung adenocarcinoma partly by acting on the 6 core targets (TP53, MAPK1, EGF, AKT1, ERBB2, and EGFR) of PI3K/AKT signaling pathway. Expressions of potential targets in lung adenocarcinoma and normal samples were analyzed by using UALCAN portal and found that ERBB2 was overexpressed in lung adenocarcinoma tissues and upregulation of it correlated with clinicopathological characteristics. Finally, quercetin repressed viabilities of lung adenocarcinoma cells by targeting ERBB2 on PI3K/AKT signaling confirmed by CCK8 and Western blot. CONCLUSION: Our finding unraveled that an active ingredient of A. membranaceus, quercetin, significantly inhibited the lung adenocarcinoma cells proliferation by repressing ERBB2 level and inactivating the PI3K/AKT signaling pathway.

Outcomes of ureteroscopy and internal ureteral stent for pregnancy with urolithiasis: a systematic review and meta-analysis.

OBJECTIVES: To investigate the outcomes of internal ureteral stents in comparison with ureteroscopy (URS) for pregnant women with urolithiasis. DATA SOURCES: Relevant studies published from January 1980 to June 2022 were identified through systematic literature searches of MEDLINE, EMBASE, Web of Science and the Cochrane Library. METHODS OF STUDY SELECTION: A total of 499 studies were initially identified. We included pregnant women in any stages of gestation who underwent double-J (D-J) stent insertion only or ureteroscopy for the treatment of urolithiasis; for a study to be included, the number of participants needed to exceed 10. This systematic review was registered on the PROSPERO website (Reference: CRD42020195607). RESULTS: A total of 25 studies were identified with 131 cases undergoing serial stenting and 789 cases undergoing URS. The pooled operative success rate was 97% for D-J stent insertion and 99% for URS. Only a few patients passed stones spontaneously after serial D-J stenting. The pooled stone free rate (SFR) in URS operations was about 91%. For internal ureteral stent therapy, the rate of normal fertility outcomes was 99%, although the pooled incidence of complications was approximately 45%. For group receiving URS treatment, the rate of normal fertility outcome was 99% and the pooled incidence of complications was approximately 1%. However, the pooled rate of premature birth and abortion were the similar between the two groups (< 1%); the rate of serious complications was also similar between the two groups. CONCLUSIONS: Although internal ureteral stents may cause more minor complications, both ureteroscopy and internal ureteral stents showed had low rates of adverse effects on fertility outcomes when used to treat pregnant women with symptomatic urolithiasis. Evidence suggests that URS may have a greater advantage for pregnant patients with urinary stones when conditions permit. Since, it has been proven to be safe and effective, internal ureteral stents could be considered in emergency or other special situations.

Base Editors for Citrus Gene Editing.

Base editors, such as adenine base editors (ABE) and cytosine base editors (CBE), provide alternatives for precise genome editing without generating double-strand breaks (DSBs), thus avoiding the risk of genome instability and unpredictable outcomes caused by DNA repair. Precise gene editing mediated by base editors in citrus has not been reported. Here, we have successfully adapted the ABE to edit the TATA box in the promoter region of the canker susceptibility gene LOB1 from TATA to CACA in grapefruit (Citrus paradise) and sweet orange (Citrus sinensis). TATA-edited plants are resistant to the canker pathogen Xanthomonas citri subsp. citri (Xcc). In addition, CBE was successfully used to edit the acetolactate synthase (ALS) gene in citrus. ALS-edited plants were resistant to the herbicide chlorsulfuron. Two ALS-edited plants did not show green fluorescence although the starting construct for transformation contains a GFP expression cassette. The Cas9 gene was undetectable in the herbicide-resistant citrus plants. This indicates that the ALS edited plants are transgene-free, representing the first transgene-free gene-edited citrus using the CRISPR technology. In summary, we have successfully adapted the base editors for precise citrus gene editing. The CBE base editor has been used to generate transgene-free citrus via transient expression.

LbCas12a-D156R Efficiently Edits LOB1 Effector Binding Elements to Generate Canker-Resistant Citrus Plants.

Citrus canker caused by Xanthomonas citri subsp. citri (Xcc) is an economically important disease in most citrus production regions worldwide. Xcc secretes a transcriptional activator like effector (TALE) PthA4 to bind to the effector binding elements (EBEs) in the promoter region of canker susceptibility gene LOB1 to activate its expression, which in turn causes canker symptoms. Editing the EBE region with Cas9/gRNA has been used to generate canker resistant citrus plants. However, most of the EBE-edited lines generated contain indels of 1-2 bp, which has higher possibility to be overcome by PthA4 adaptation. The adaptation capacity of TALEs inversely correlates with the number of mismatches with the EBE. LbCas12a/crRNA is known to generate longer deletion than Cas9. In this study, we used a temperature-tolerant and more efficient LbCas12a variant (ttLbCas12a), harboring the single substitution D156R, to modify the EBE region of LOB1. We first constructed GFP-p1380N-ttLbCas12a:LOBP, which was shown to be functional via Xcc-facilitated agroinfiltration in Pummelo (Citrus maxima) leaves. Subsequently, we stably expressed ttLbCas12a:LOBP in Pummelo. Eight transgenic lines were generated, with seven lines showing 100% mutations of the EBE, among which one line is homozygous. The EBE-edited lines had the ttLbCas12a-mediated deletions of up to 10 bp. Importantly, the seven lines were canker resistant and no off-targets were detected. In summary, ttLbCas12a can be used to efficiently generate biallelic/homozygous citrus mutant lines with short deletions, thus providing a useful tool for the functional study and breeding of citrus.

Highly Efficient Generation of Canker-Resistant Sweet Orange Enabled by an Improved CRISPR/Cas9 System.

Sweet orange (Citrus sinensis) is the most economically important species for the citrus industry. However, it is susceptible to many diseases including citrus bacterial canker caused by Xanthomonas citri subsp. citri (Xcc) that triggers devastating effects on citrus production. Conventional breeding has not met the challenge to improve disease resistance of sweet orange due to the long juvenility and other limitations. CRISPR-mediated genome editing has shown promising potentials for genetic improvements of plants. Generation of biallelic/homozygous mutants remains difficult for sweet orange due to low transformation rate, existence of heterozygous alleles for target genes, and low biallelic editing efficacy using the CRISPR technology. Here, we report improvements in the CRISPR/Cas9 system for citrus gene editing. Based on the improvements we made previously [dicot codon optimized Cas9, tRNA for multiplexing, a modified sgRNA scaffold with high efficiency, citrus U6 (CsU6) to drive sgRNA expression], we further improved our CRISPR/Cas9 system by choosing superior promoters [Cestrum yellow leaf curling virus (CmYLCV) or Citrus sinensis ubiquitin (CsUbi) promoter] to drive Cas9 and optimizing culture temperature. This system was able to generate a biallelic mutation rate of up to 89% for Carrizo citrange and 79% for Hamlin sweet orange. Consequently, this system was used to generate canker-resistant Hamlin sweet orange by mutating the effector binding element (EBE) of canker susceptibility gene CsLOB1, which is required for causing canker symptoms by Xcc. Six biallelic Hamlin sweet orange mutant lines in the EBE were generated. The biallelic mutants are resistant to Xcc. Biallelic mutation of the EBE region abolishes the induction of CsLOB1 by Xcc. This study represents a significant improvement in sweet orange gene editing efficacy and generating disease-resistant varieties via CRISPR-mediated genome editing. This improvement in citrus genome editing makes genetic studies and manipulations of sweet orange more feasible.

Factors Influencing Surgical Outcome in Retrograde Management of Parapelvic Renal Cysts.

Objective: To investigate the outcomes of retrograde flexible ureteroscopy in managing parapelvic renal cysts and speculate the factors affecting therapeutic efficacy. Methods: Thirty-eight patients with parapelvic renal cysts were recruited and underwent retrograde flexible ureteroscopy using holmium laser. Parapelvic cysts were divided into peripheral type and central type based on the position of cyst convex to the perirenal tissue. Feasibility and safety were retrospectively evaluated, and cases were analyzed to detect their distinctive characteristics. Independent-sample t-test and chi-square test were undertaken for continuous variables and categorical variables, respectively. Results: Radiologic evidence of success was achieved in 31 (81.58%) cases after a mean follow-up of 14.4 months (range 6-26 months). No significant perioperative complications were identified. There were seven cases with features of peripherally located parapelvic cyst. Four cysts shown as irregular protrusion were unable reduce to less half of previous size. Reductions were recorded in the other three patients with spherically peripheral protrusion. There was significant difference between these two types (p = 0.029). Among the 31 patients with centrally located parapelvic cyst, 28 of these have simple cysts that achieved radiologic success and 3 of the 31 patients were identified as failed cases indicated by renal pelvis enveloped by cyst on radiologic investigation. The success rate of simple cysts was significantly higher than that of the later type (p < 0.001). Conclusion: The location and shape of parapelvic cyst may play a critical role in the radiologic outcome of internal incision and patients with simple central or spherical peripheral cyst may benefit more from retrograde flexible ureteroscopy combined with laser incision.

Acupuncture for opioid-induced constipation: Protocol for a systematic review and meta-analysis.

BACKGROUND: Opioid-induced constipation (OIC) is one of the most common complications of analgesic therapy for cancer pain patients who suffer moderate to severe pain. Acupuncture as an effective treatment in constipation has been widely applied. But its efficacy has not been assessed systematically. Thus, the purpose of this study is to provide a protocol to explore the efficacy and safety of acupuncture for OIC. METHODS: Randomized Controlled Trials (RCTs) of acupuncture treatment for OIC in 4 Chinese electronic databases (China National Knowledge Infrastructure, Chinese Biological and Medical Database, China Scientific Journal Database, Wan-Fang Data) and 3 English electronic databases (PubMed, Embase, Cochrane Library) will be searched from their inception to September 31, 2020. RevMan 5.3 software and Stata 14.0 software will be used for meta-analysis, EndNote X9.2 and Cochrane Risk of Bias Tool will be used for literature screening and quality assessment. RESULTS: This study will present an assessment of the efficacy and safety of acupuncture treatment for OIC patients through summarize high-quality clinical evidence. CONCLUSION: The conclusion of our systematic review and meta-analysis may provide evidence of whether acupuncture treatment is beneficial to patients with OIC.INPLASY registration number: INPLASY2020100026.

Development of multiplex genome editing toolkits for citrus with high efficacy in biallelic and homozygous mutations.

KEY MESSAGE: We have developed multiplex genome editing toolkits for citrus that significantly improve citrus genome editing efficacy. CRISPR/Cas systems have been engineered for genome editing in many organisms, including plants. However, the gene editing efficiency in citrus via CRISPR technology remains too low to be implemented for genetic improvement in practice. Moreover, it is very difficult to obtain homozygous or biallelic knockout mutants in citrus. Here, we have developed multiplex genome editing toolkits for citrus including PEG-mediated protoplast transformation, a GFP reporter system that allows the rapid assessment of CRISPR constructs, citrus U6 promoters with improved efficacy, and tRNA-mediated or Csy4-mediated multiplex genome editing. Using the toolkits, we successfully conducted genome modification of embryogenic protoplast cells and epicotyl tissues. We have achieved a biallelic mutation rate of 44.4% and a homozygous mutation rate of 11.1%, representing a significant improvement in citrus genome editing efficacy. In addition, our study lays the foundation for nontransgenic genome editing of citrus.

GBX2, as a tumor promoter in lung adenocarcinoma, enhances cells viability, invasion and migration by regulating the AKT/ERK signaling pathway.

BACKGROUND: Increasing evidence shows that gastrulation brain homeobox 2 (GBX2) is involved in multiple cancers. However, whether GBX2 has an effect on the lung adenocarcinoma remains unclear. In the present study, we investigated the functions of GBX2 on lung adenocarcinoma and explored the underlying mechanism. METHODS: Public data were obtained from the TCGA (https://cancergenome.nih.gov) and Oncomine (http://www.oncomine.org) databases. GBX2 expression and its prognostic value were analyzed by bioinformatics methods. Relative mRNA and protein expression levels of GBX2 in lung adenocarcinoma cell lines were evaluated via a quantitative reverse transcriptase polymerase chain reaction and western blotting. Lung adenocarcinoma cell lines LTEP-a-2 and A549, respectively, were selected for gain and loss function of GBX2 assays. Cell viability was detected by CCK8 and clone formation experiments. Cell invasion and migration were assessed by Transwell assays. The effect of GBX2 on the AKT/extracellular signal regulated kinase (ERK) pathway was tested by western blotting. RESULTS: Compared to adjacent tissues, GBX2 expression was up-regulated in lung adenocarcinoma tissues. High expression of GBX2 led to a poor survival and could be seen as an independent predictor for lung adenocarcinoma patients. Furthermore, down-regulation of GBX2 notably restrained the viability, invasion and migration abilities of A549 cells, whereas up-regulation of GBX2 in LTEP-a-2 cells presented the opposite outcomes. Furthermore, western blot indicated that down-regulation of GBX2 decreases the protein levels of phosphorylated (p)-AKT and p-ERK in A549 cells, whereas up-regulation of GBX2 shows the opposite effects in LTEP-a-2 cells. CONCLUSIONS: The results of present study indicate that GBX2 acts a cancer-promoting role to accelerate cell proliferation, invasion and migration partly by modulation of the AKT/ERK pathway in lung adenocarcinoma.

Relationship of common variants in Interleukin 33 gene with susceptibility and prognosis of osteosarcoma in Han Chinese population.

Osteosarcoma (OS) is one of the most common malignant bone tumors. Many previous studies have indicated that OS is a complex disease and that its development may be affected by multiple genetic factors, which may contribute to its carcinogenesis. The aim of the present study was to evaluate the relationship of IL-33 with susceptibility and prognosis of OS in Han Chinese individuals. A total of 1,605 study subjects including 507 OS patients and 1,098 controls were recruited. Eighteen SNPs mapped to IL-33 were selected for genotyping. Genetic associations between selected SNPs and OS disease status were evaluated. Survival analyses, including Kaplan-Meier analysis and Cox model fitting for significant SNPs, were performed. The functional consequences of significant SNPs were analyzed using a publicly available database. SNP rs1048274 was identified to be significantly associated with OS disease status (OR=0.75, P=1.53×10-4). Compared to the GA and GG groups, OS patients with the AA genotype of rs1048274 had better survival rate. The hazard ratio of SNP rs1048274 (AA group compared to GG+GA group) was 0.35 (95% confidence interval of 0.25-0.5) following adjustment for several clinical variables. In conclusion, our results suggested that IL-33 may play a key role in the etiology of OS, indicating IL-33 as a potential genetic risk factor of the development and prognosis of OS.

[Rasch analysis on stroke-specific quality of life (SS-QOL) scale of acupuncture intervention on stroke].

OBJECTIVE: To optimize the evaluation level of active motor threshold and the functional domain of upper limbs of stroke-specific quality of life (SS-QOL) scale with Rasch analysis. METHODS: Sixty patients with acute ischemic stroke that were in accord with research criterid were randomly divided into a test group (30 cases) and a control group (30 cases). Acupuncture treatment and routine western medicine were applied on the test group, and single treatment of routine western medicine was applied on the control group. Selected acupoints were MS 5, Fengchi (GB 20), Hegu (LI 4), etc. Active motor threshold and the functional domain of upper limbs of SS-QOL were self-tested by patients after one treating course. The characteristics of the above mentioned items were tested with Rasch model. RESULTS: The statistical result on fitness of active motor threshold and the functional domain of upper limbs of SS-QOL showed that every reference of samples and items wosin accord with the Rasch model and has well inner reliability and validity. The Infit and Outfit MnSq values of active motor threshold and the functional domain of upper limbs of SS-QOL are basically between 0.5 and 1.5. CONCLUSION: The application of Rasch analysis on the assessment of patient reported outcome (PRO) has optimized the PRO scale (the activity and upper limb function domain of SS-QOL scale) and enhanced evaluation level of active motor threshold and the functional domain of upper limbs of SS-QOL scale.